NO128527B - - Google Patents

Description

Procedure for the oxidation of olefins to aldehydes, ketones and acids.

It is known to oxidize ethylene catalytically with silver-containing catalysts to ethylene oxide and with other oxidation catalysts at higher temperatures to mixtures of foraldehyde, acetaldehyde, formic acid, acetic acid and other products. In this way, it has not been possible to obtain acetaldehyde or acetic acid in economically interesting yields. According to our own experiments, only small yields of acetaldehyde were obtained under such conditions, even with noble metal catalysts, and formaldehyde was usually heavily outweighed in terms of quantity.

Furthermore, it is known that compounds of

palladium, platinum, silver or copper form complexes with ethylene. During the cleavage of the potassium-platinum complex, the formation of acetaldehyde was observed. Other unsaturated compounds can have a beneficial effect on the complex formation. But here we are dealing with stoichiometric reactions, where the precious metal is obtained as such.

Furthermore, it has already been described to reduce palladium chloride in the presence of water with the aid of ethylene to palladium metal, the formation of acetaldehyde being observed.

Finally, it has already been described that

propylene causes a rapid and complete reduction of palladium chloride dissolved in water to palladium, even if the propylene is

mixed with nitrogen or air. Also the reduction which takes place under the same conditions of palladium chloride by means

of isobutylene is already known, since carbon dioxide is not developed in the same way as with the impact of ethylene and propylene.

The invention relates to a method for the production of aldehydes, ketones or acids corresponding to the aldehydes, by oxidation of olefins in the liquid phase in the presence of water and compounds of noble metals from the 8th group of the periodic table in a neutral to acidic medium, and the method is characterized by the oxidation is carried out using oxygen, optionally mixed with inert gases and in the presence of redox systems.

For example, Redox systems are relevant which contain compounds of metals which, under the reaction conditions used, can occur in several oxidation stages, e.g. compounds of Cu, Hg, Ce, Tl, Sn, Pb, Ti, V, Sb, Cr, Mo, U, Mn, Fe, Co, Ni, Os, but also other inorganic redox systems such as sulphite/sulphate, arsenite /arsenate, iodide/iodine and/or organic redox systems such as azobenzol/hydrazobenzol, quinone or hydroquinone of the benzol, naphthalene, anthracene or phenanthrene series. As compounds of noble metals from the 8th group of the periodic table are e.g. the compounds of palladium, iridium, ruthenium, rhodium or platinum relevant. Compounds of this metal class are able to form addition compounds or complexes with tylene. Oxygen is suitable as an oxidizing agent, possibly in a mixture with inert gases.

For example, you can use the oxygen in the form of air. But for the use of air as the cheapest oxidizing agent, certain limits have been set if the unreacted gases are circulated, as the nitrogen is enriched as ballast. Instead of ethylene, gas mixtures containing ethylene can also be used, in which e.g. saturated coal water substances are present. Furthermore, the reaction can also be carried out in the presence of precious metals.

The reaction can be supported by the addition of active oxidizing substances, such as ozone, peroxide compounds, especially hydrogen peroxide, oxygen compounds of the nitrogen substance, free halogen, halogen oxygen compounds, compounds of the higher value levels of metals such as Mn, Ce, Cr, Se, Pb, V, Ag, Mo, Co, Os. Additions of such active oxidizing substances facilitate the recovery of the higher oxidation step necessary for the reaction by the active catalyst component. These active oxidizing substances can also be produced first during the reaction. Optionally, oxidation catalysts can also be added. It may be appropriate to add, before or during the reaction, compounds which, under the reaction conditions used, give off anions, e.g. inorganic acids or salts, halogens, halogen-oxygen compounds, or also organic substances, preferably saturated low molecular weight aliphatic halogen compounds. In this way, possible depletion of anions can be counteracted and the lifetime of the catalyst extended.

The present method can be carried out in solution at relatively low temperatures. Optionally, one can also work with a slurry of the catalyst (sludge catalyst) in water, or an aqueous solvent, e.g. aqueous solution of acetic acid, glycol, glycerin, dioxane or mixtures of these, so that the catalytically active substances are present in high concentration. This embodiment has the further advantage that the heat of reaction can thereby be carried away very well and that the turnover can be increased very strongly. Surprisingly, this method of working with a sludge catalyst also has a further advantage, in that a good foam formation causes an extremely fine gas distribution, which naturally favors the reaction. In the case of a correct production of the foam — such as, for example occurs by varying the amount of gas and the gas distribution — it is achieved that possibly half, or even only a third of the catalyst amount is sufficient to fill the entire reaction space and to participate completely in the reaction. Thereby, significant amounts of catalyst can be saved, which leads to a further economy of the method.

Such a sludge catalyst can be produced by a simple slurrying of the catalyst - the components with such an amount of water or aqueous solvent that is not sufficient for the dissolution of the total amount of salt. Of course, a certain amount of the catalyst-active salts is always found in the solution and only as much is present as a bottom deposit, or as a slurry, which corresponds to the exact reaction conditions present. An addition of foreign substances is indeed possible, but usually unnecessary, because the solid bodies in the catalyst should preferably themselves consist of catalyst-active substances. The quantity of the catalyst sludge can vary within very wide limits and should suitably amount to between 5 and 90 per cent of the total volume.

A particularly advantageous way of producing a sludge catalyst is the co-use of iron salts as a catalyst. The iron salt is dissolved with the other catalyst components in water and acetic acid or salts of the acetic acid are added. At room temperature or when heated to the working temperature, the iron salt hydrolyzes and forms a very fine iron hydroxide sludge which is particularly beneficial for the purposes of the present method. The same precipitating effect is also achieved when the acetic acid that forms after a longer reaction time in the reaction liquid comes into effect, resp. when most of the hydrochloric acid on hand has decreased so much by partial neutralization or by the formation of by-products, that a hydrolysis of the iron salt can take place. In this case, the working method, which begins in the liquid phase, slowly transitions into the sludge phase. The precipitation of the iron sludge can be slowed down or reduced by the addition of acid.

Although working with sludge catalysts is particularly advantageous if iron salts are present in the catalyst, such embodiments are also relevant where compounds of other metals are contained as redox systems, e.g. copper, cerium, antimony, manganese, chromium, titanium, tin, thallium, uranium, alone or suitably in mixture with iron compounds. Furthermore, it is possible to use catalyst mixtures, in which, for example, compounds of the aforementioned metals are present in a mixture with compounds of other elements that can occur in several oxidation stages, e.g. compounds of mercury, vanadium, lead, osmium, selenium.

Sometimes it turns out that the sludge catalyst's activity decreases after some time, as coarse-grained particles form over time. In this case, the activity of the catalyst can be improved again if the sludge is removed from time to time in whole or in part, or if part of the sludge is continuously removed and dissolved in mineral acid, preferably hydrohalic acid, such as hydrochloric acid, the acid being appropriately used in approximately the calculated amount and returns the solution to the system. In this way, the anion concentration in the liquid can also be regulated. Optionally, before dissolution in the acid, the sludge can also be subjected to a thermal treatment at a relatively low temperature and then at such a temperature that no formation of acid-insoluble oxides occurs. In particular, the sludge is annealed at a weak red glow to remove organic components.

The dosing of the reaction gas by means of sintered glass mass is less suitable when using sludge catalysts because blockages can easily occur. More advantageously, the gas can be introduced through a nozzle, which does not cause any disadvantages due to the special tendency of these catalysts for fine gas distribution.

When using recirculation or 2-stage apparatus, or flow pipes, the liquid that stands above the bottom deposit, but as much as possible the overall homogeneous catalyst suspension, should not flow in a circuit. In most cases, it is possible to achieve a satisfactory catalyst circuit without the use of pumps, especially with the aid of foam formation. However, it is also possible to use suitable pumps.

The method according to the invention can be particularly advantageously carried out at temperatures from 50 to 160°C, preferably from 50 to 100°C, as when working in the liquid phase it is necessary to work at elevated pressure if you work at temperatures above 100°C. Optionally, higher temperatures can also be used, e.g. 170 to 180°C, or lower e.g. 40°C or work in other areas, e.g. from 80 to 120°C. Furthermore, it is essential to work in an acidic to neutral area. pH values from 0.8 to 3 are preferred, however it is also possible to work at higher pH (e.g. between 0.8 and 5 or 2 and 6) or lower pH values (e.g. 0, 5), although there are usually no special advantages associated with this.

As it has been found, by working in the liquid phase, by means of a change in the ratio of olefin to oxygen, sometimes occurring difficulties can be removed. These difficulties can consist in the fact that formed cupric (I) chloride or other compounds fall out and cause blockages, which produces unwanted operational disturbances. As these precipitated salts are no longer available to increase the reaction, the yield decreases more or less rapidly. The point in time at which such a change in the ratio of olefin to oxygen is to be made can be easily determined by means of a continuous pH measurement. If the pH value decreases, the reaction can be brought back to the optimum pH range by means of a stronger dosage of oxygen, or a weaker dosage of olefin, resp. by both precautions. If the pH value rises, the optimum pH range can be set again by reversing the precautions. One can also combine this method to control the reaction with the above-mentioned addition of anion-releasing compounds, e.g. of hydrohalic acids or of organic compounds which split off hydrohalic acids under the experimental conditions, or also of acidic salts. It is particularly advantageous at the beginning of the reaction to adjust to a specific pH, for example with hydrochloric acid, and only during the ongoing reaction to control the olefin-oxygen dosage. Of course, you can also change the suitable pH value during the reaction by adding acid.

The pH measurements are best carried out with one of the usual instruments. One can either carry out continuous measurements with electrodes built into the reactor, or carry out discontinuous measurements, taking samples at certain time intervals and determining their pH value.

A special technical embodiment of this method consists in an automatic connection of the pH measuring device with the dosing device for ethylene and oxygen. Once the pH is optimally set, the reaction is controlled automatically.

In some cases, the presence of salts such as NaCl or KC1 can also be beneficial. For example, these salts — like hydrochloric acid itself or other alkali or alkaline earth halides such as LiCl, CaCl2, MgCI2 or other salts such as FeCI2 or CuCl2 — cause an improvement in the solubility of CuCl, which can be formed during the reaction and which is only very little soluble in water (0.11 per cent at 80°C). An improvement in the solubility of CuCl can also be achieved by adding formic acid, but even better can halogenated acetic acids or their salts are used as solubilizers, especially when using catalysts containing copper chloride. These compounds have a very strong dissolving effect for CuCl and therefore only need to be added in small amounts, generally 1 to 50 per cent, referred to the copper contained in the solution calculated as CuCl2. 2H20. The reduction of the oxygen solubility in the catalyst liquid, which is caused by the presence of the necessary large quantities of other additives, is consequently very small. The advantage of the addition of halogen-acetic acid or its salts lies in the fact that, by adding these compounds, precipitation of CuCl during the reaction is prevented and thereby a reduction in turnover and operational disturbances are avoided. But by keeping CuCl in solution, there is always a high Cu(I)-ion concentration at the same time, which is available for a reaction with the more or less present oxygen. This favors the desired rapid oxidation to the easily soluble CuCl2 — which is presumably the rate-determining step for the overall reaction — and the overall reaction is accelerated.

Of the halogenated acetic acids, trichloroacetic acid and also dibromoacetic acid are particularly effective. For example, the solubility of CuCl in 2.5% aqueous trichloroacetic acid is more than 50 times the solubility in water. With similar results, the salts of the halogenoacetic acids, mixtures of the salts, or their mixtures with the free halogenoacetic acids can also be used. As salts, those with inorganic cations as well as those with organic bases are relevant. Examples include salts of alkalis, ammonia, earth alkalis, e.g. sodium, potassium, lithium, magnesium, calcium, barium, iron, copper, palladium, cerium and others, further salts of triethylamine, tripropylamine, di- and/or triethanolamine.

The use of the above-mentioned salts instead of the free haloacetic acids hal-

the advantage is that a too strong recruitment and the associated decline in turnover is avoided. The quantities that are most suitable for the addition depend on the possible catalyst composition. By a catalyst, which contains 100 g of CuCl2. 2H20 and 2 g of PdCl2 in 1 liter of water, it is sufficient to add 20-25 per cent trichloroacetic acid, or the equivalent amount of its salt, the percentage being referred to the amount of cupric chloride calculated as CuCl2. 2H20. In the case of the above-mentioned additions, a smooth course of reaction and an increase in turnover are therefore achieved in the production of carbonyl compounds from olefins.

The present method can be carried out at normal pressure as well as at increased or reduced pressure, e.g. at pressures up to 100, preferably up to 50 ato. The application of pressure is possible, as well if one works at temperatures above 100°C, as if one uses temperatures below 100°C.

Furthermore, the course of the reaction can be supported by increasing the concentration of the ethylene and/or the oxygen in the reaction space. This can be achieved, for example, by increasing the pressure and by using solvents. Thus, one can significantly increase the ethylene concentration in the reaction solution — by using higher concentrations of ethylene-binding metal salts, for example of copper, iron, mercury or iridium compounds, especially the halides, or in the event that mercury is used also the sulfate, or of organic, preferably water-miscible solvents, e.g. acetic acid, mono- or poly-alcohols, cyclic ethers, dimethylformamide. Optionally, the gas can also be fed into a circuit, e.g. a gas that still contains a few percent of unconverted oxygen.

Due to the presence of oxidizing agents, in addition to acetaldehyde, acetic acid can also occur in smaller quantities. Optionally, one can also connect the further oxidation of the acetaldehyde to acetic acid with the reaction described above using the known oxidation experiences, and thus partially or completely skip the aldehyde step, or also further oxidize the acetaldehyde in another step to acetic acid.

Furthermore, it was found that under the above-mentioned conditions under which ethylene gives acetaldehyde, propylene predominantly forms acetone and next to it propionaldehyde. From α- and β-butylene, you get predominantly methyl ethyl ketone from α-butylene, in addition to butyraldehyde. From isobutylene, isobutylaldehyde can be recovered.

In the case of the higher olefins such as pentene and the homologue, cyclohexene, styrene, the reaction proceeds in a much analogous manner and can be carried out under the same conditions as described above. Because of the relatively mild reaction conditions, almost only the oxidation products that are to be expected due to the structure occur, without isomerization or molecular cleavage occurring in significant quantities.

Of course, mixtures of olefins or olefinic gases, or other unsaturated compounds such as diolefins, are reacted in the same way as long as they are reactive under the given conditions, although the reaction of olefins with 2 to 3 C atoms is preferred. In certain cases, the reaction conditions must be adapted to the compounds used and their physical properties. The higher boiling points of the reaction products may also require a corresponding change in the process conditions. For example, diacetyl can be obtained from butadiene.

For stoichiometric reasons, the complete oxidation of olefins to the corresponding aldehydes or ketones the mole ratio of olefin bond to oxygen be 2:1. Due to the explosion safety, however, it is advantageous to work with an oxygen deficit, e.g. in the range of 2.5:1 to 4:1. Even better is working outside the explosion area, e.g. with an oxygen content of 8-20 percent or under pressure at 8-14 per cent, and carries the unreacted gas which mainly consists of excess olefin or any inert gases such as nitrogen in the circuit and complement the ethylene and oxygen in relation to their consumption. The present method can be carried out in such a way that the olefin is brought into contact with oxygen or air at the same time as the contact substance. Sometimes it may also be appropriate to bring the olefin and the oxidizing agent separately into contact with the catalyst medium. This has the advantage that the composition of the gas mixture does not need to be carefully monitored and that air can also be used as an oxidizing agent during the return of the ethylene in the circuit without having to incur any disadvantages. This embodiment can be carried out in such a way that the olefin and the oxidizing agent are brought into contact with circulating catalyst liquid in periodic exchange in a vessel, as for continuous execution a mutually switchable double apparatus can also be used, or by a continuous process in several reaction rooms. In this embodiment, instead of pure olefin, mixtures of oxygen and olefin can also be used, whose oxygen content is below the explosion limit and which, e.g. contains 1 to 10 per cent, preferably between 3 and 10 per cent oxygen, referred to the amount of olefin present. The explosion limit is e.g. for ethylene-oxygen mixtures at normal pressure at 20.1 percent oxygen. In this varied embodiment, the catalyst medium is then in a further separate step brought into contact with a sufficient amount of oxidizing agent for the regeneration, e.g. oxygen or air under known conditions, e.g. at 50-150°C. In this way, depending on the conditions, the olefin that is dissolved in the catalyst medium is optionally also oxidized or therein dissolved reaction product driven off from the catalyst medium. In order to achieve a good stripping effect, you can optionally also use mixtures of oxygen or air with water vapor for the regeneration.

The working method of bringing the olefin and the oxidizing agent separately into contact with the catalyst medium offers the advantage that under normal pressure, but especially when working under pressure, it is still possible to work with gas mixtures that lie below the flame limit and thus allow completely safe work.

Compared to the embodiment of bringing pure olefin and oxidizing agent into contact with the catalyst medium, the use of mixtures of olefin with little oxidizing agent on the one hand and oxidizing agent on the other side offers the further advantage that at the point where an olefin-oxygen mixture enters in the reactor and which contains less oxygen than that which corresponds to the stoichiometric composition with regard to the conversion to carbonyl compound and whose composition is below the flame limit, a separation of unwanted solids which sometimes occurs is avoided. Such a precipitation of solids would, however, condition a depletion of the catalyst liquid in catalyst active substance and thus a reduction of the catalyst activity or on the other hand, unwanted clogging of lines, taps, nozzles and the like. However, such separations do not occur if the olefin is brought into contact with the catalyst solution in the first step in a mixture with a small amount of oxygen or air and in a second step the catalyst solution is regenerated by further oxidizing agent. If you bring the olefin and the oxidizing agent resp. an olefin containing a small amount of oxygen and the oxidizing agent, e.g. oxygen as described above separated in contact with the catalyst, it may be appropriate to free the catalyst solution that has been treated with the olefins from residues of unreacted olefin and reaction product by suitable means such as stronger heating or stripping with an inert gas such as nitrogen or water vapor before bringing them together with the oxidizing gas in the second phase. By connecting the head piece of the one-phase reaction tower with the lower liquid inlet of the regeneration tower and vice versa, a closed liquid circuit can also be produced, so that pumps are not necessary. The rising gas flows then put the liquid into vigorous circulation, which can possibly be measured by flow meters and the like. One can also provide the reaction tower with extended upper parts in which the foam collapses and the gas and liquid separate. In the event that it is feared that the mixture of residual oxygen resp. the residual air and the aldehyde e.g. the acetaldehyde may exceed the lower explosion limit somewhat, in practice known safety devices against puffing can be placed at the head of the reaction tower, such as rice discs, flame traps ("Kiestøp-fe") and the like. Due to the saturation of the acetaldehyde-air mixture with water vapor and the relatively low oxygen content, which is less than in air, the risk of puffing is very small. These embodiments of the method have the common advantage that no explosive gas mixtures can form, even when working under elevated pressure, and that each of the two gas streams moves independently in a circuit and can be supplemented to the necessary extent with fresh gas. The use of air as an oxidizing agent is also possible without further ado, as an enrichment of nitrogen thereby has a disturbing effect.

A much more appropriate technical embodiment of the present method consists in separating the desired reaction product from the reaction gas, e.g. the acetaldehyde, again leads into the reactor the remaining, mostly still oxygen-containing residual gas, and introduces an amount of olefin, which is as large as that consumed by the reaction, as well as oxygen separated from the cycle gas, by the liquid catalyst best at the bottom. But you can also proceed so that you add to the residual gas an amount of ethylene corresponding to the amount consumed and direct this gas mixture, e.g. contains 90-95 percent olefin (e.g. ethylene) and 10-15 percent oxygen separately into the reactor. The oxidizing agent can then be introduced most appropriately below the point where the residual gas is introduced, or if you are working with a circulating catalyst, already in the catalyst circulation line. Thereby, the amount of oxygen can be varied so that even in the catalyst solution, the explosion limit is never exceeded. But usually this is not necessary, it is sufficient if the oxygen is dosed so that the residual gas that escapes from the catalyst solution only has a composition that lies outside the explosion limit.

In order to achieve a particularly high space-time yield, one can of course also introduce olefin or oxygen, or both, into inlets which, however, are most appropriately spatially separated from each other, at different places that lie one above the other in the reaction vessel, for example in a reaction tower, since the amount of oxygen can also be measured so that it does not exceed the lower limit of the explosion area anywhere in the device.

Furthermore, it has sometimes proved advantageous to additionally add dispersants, e.g. an alkylphenyl sulfonate, and/or protective colloids. If necessary, particularly with sludge-free liquid catalysts, finely divided solids can also be added. The effect of these substances is due to the fact that the catalyst sludge is particularly finely divided or that intermediately formed free noble metal, which in the present method due to the reaction participants is again transferred into active compounds, cannot aggregate into larger particles. You thus achieve a particularly fine and constant degree of distribution of the catalyst. As solid substances in powder form are e.g. coal powder, diatomaceous earth or similar relevant. It is also possible to use combinations of dispersants, protective colloids and finely divided solids.

Furthermore, it was found that in many cases a particularly easy reaction is possible, if one uses catalysts which contain only a small amount of compounds of noble metals from the 8th group. For example, it is often sufficient if the ratio between the sum of the redox metals, especially the sum of copper and iron, to the precious metal, especially to palladium, is at least 15:1, but preferably 25-500:1. But it is preferred to work with catalysts containing copper salts, in which the ratio of copper to palladium amounts to more than 10:1, e.g. more than 15:1, preferably 50:1 to 500:1. Optionally, the mentioned ratios can also be even higher. This method of working has the further advantage that it is more economical, as only small amounts of the expensive palladium salts are required. It is suitable for the conversion of ethylene as well as of other olefins and can be combined as desired with the previous and following embodiments. For example, work can also be done under pressure, or the olefin and the oxidizing agent are brought separately into contact with the catalyst medium.

As already stated, the olefins can also be used in the form of olefin-containing, e.g. ethylene-containing gas mixtures. Such gas mixtures can, as was further found, contain, for example, carbon oxide and/or hydrogen in addition to saturated coal water substances. Even in the presence of these gases, the course of the reaction is surprisingly not influenced, as in the case of CO, appropriately at least as much oxygen is present as is necessary for a conversion of the olefin at hand to aldehyde and CO to CO 2 . But it is believed that the present reaction proceeds via the formation of olefin noble metal complexes as intermediates, which then react with water to the carbonyl compounds. But it is known from the literature that carbon monoxide displaces all olefins, including ethylene, from these coordination compounds. For these reasons, it should be expected that a mixture of olefins with carbon monoxide would show no, or only a very small conversion of olefins to carbonyl compounds. It must therefore be seen as surprising that the carbon oxide olefin mixture, possibly also in a mixture with other inert gases for the reaction, practically gives the same yields of carbonyl compounds as if the carbon oxide were not present. In this reaction, the carbon monoxide is partially converted into carbon dioxide.

As is known from the literature, hydrogen reacts very similarly to carbon monoxide and it is therefore just as surprising that the olefin oxidation proceeds completely without disturbances in its presence. The largest part of the water substance remains unchanged, while a smaller part reacts to form water and another smaller part during hydrogenation of the olefin.

When using mixtures of carbon monoxide and hydrogen with the olefin or olefinic gases, carbonyl compounds are obtained in the same way without a reduction in yield, since the application of pressure has a favorable effect on the conversion.

The fact that neither hydrogen nor carbon monoxide interferes with the implementation of the present method is of particular importance when using technical gases, e.g. refinery - gas or crack gas as starting materials. The expensive gas separation is thereby redundant - although a pre-purification or an enrichment of the olefin may be appropriate - so that a significantly cheaper raw material is used.

The carbon oxide and/or water may be present in the gas mixture, e.g. in such an amount that their proportion is twice that of the olefin. Despite this, the olefin oxidation is not significantly influenced thereby. With these indications, however, no limits shall be set. It is particularly appropriate in the presence of these gases to use the multi-stage method described above, whereby the olefin, possibly mixed with small amounts of oxygen, is brought into contact with the catalyst in one step and the oxidizing agent in another step, or other device. Thereby, a mixture of the gases used with oxygen can practically be avoided, so that after they leave the reactor they are still available for other purposes.

After corresponding processing, the reaction's exhaust gases can be used again or carried in a circuit. Examples of inert gases for the reaction which can also be mixed include nitrogen, carbon dioxide, methane, ethane, propane, butane, isobutane and other saturated aliphatics, as well as cyclohexane, benzene, toluene and the like.

In the simultaneous production of carboxylic acids and aldehydes using sludge catalysts, which contain iron, manganese and/or cobalt salts, other redox systems, such as copper compounds, can also be added. For example, copper can thereby be used in such quantities that the ratio between copper and palladium, as mentioned above, amounts to more than 10:1.

The catalysts used in the present reaction can, over time, be depleted of halogens, which may result in a decrease in turnover. The loss of halogen can be counteracted, as already stated above, by adding halogen or hydrohalogen acid or organic substances, which split off halogen or hydrohalogen acid under the experimental conditions.

As it was determined, this halogen depletion is essentially due to the formation of 1 volatile halogenated by-products, e.g. of chloromethyl, chloroethyl, etc., which, together with the carbonyl compounds obtained, expel the halogen from the catalyst more or less rapidly. It was found that during the reaction a certain amount of the carbonic acid corresponding to the olefin is formed, e.g. acetic acid, which accumulates in the liquid, causing an increase in the solubility of the reaction products. Thereby, the formation of halogen-containing volatile by-products is favored, whereby halogen depletion is promoted. Moreover, the enriching carboxylic acids, especially acetic acid, have an unfavorable effect on the reaction with the copper ions because the formed copper salts such as the copper acetate are relatively inert to the olefin oxidation. Therefore, it is often appropriate to counteract the enrichment of these carboxylic acids in the reaction space and to ensure the lowest possible content of these acids. This can be done by suitable continuous or discontinuous precautions, for example by distillation, extraction or precipitation. A preferred embodiment consists when working under normal pressure, e.g. whereby the carbonic acid is allowed to distill out with the water that evaporates in the reaction chamber, and replaces the water loss with fresh water. The amount of carbonic acid, which is removed in this way, depends on the surface of the reactor, the temperature and the amount of gas flowing through and can be varied by changing these factors. Another embodiment consists in working up the overall catalyst solution, removing the carbonic acid contained in it and returning the catalyst solution.

In order to avoid operational disturbances, you can also lead away part of the catalyst liquid periodically or . continuously, or if working with a catalyst sludge separate from the sludge and liberate carbonic acid completely or extensively, e.g. by distillation and again adding the obtained liquid to the catalyst medium.

Since, as was further found, the achieved conversion depends among other things on the molar ratio between copper and halogen, it has been shown to be most beneficial to maintain the molar ratio between copper and halogen with copper-containing catalysts, and even when working with solid as well as with liquid, especially aqueous catalyst, between 1:1 and 1:2, preferably from

:1.4 to 1:1.8. Therefore, it is appropriate to work in a liquid catalyst to precisely dose the halogen that is added at the beginning of the reaction.

In the case of specified cup: halogen for iold, the amount of halogen must be included

>if added in the form of iron halide or other halides of such cations, which do not form neutrally reacting salts with the halogen hydrogen acid, but the amount present in the form of neutral salts need not be taken into account, e.g. as NaCl or KC1, or resp. can be tied. If, for example, alkali or alkaline earth salts of other acids such as the halogen hydrogen acids are added to the catalyst, for example 3 gram equivalents per liters and contains

the catalyst 5 g equivalents (mol) of chlorine ions, which were added in the form of ferric chloride and one mole of copper ions, which were added in the form of copper acetate, so the copper-chlorine ratio according to the above definition is 1:2.

At a lower halogen content than that which corresponds to 1:1, the turnover goes back. Then you can again quickly produce the optimal ratio, for example by adding halogen hydrogen, e.g. of hydrochloric acid. If the contact is separately brought into contact with the olefin and the oxidizing gas, as described above, in different embodiments, then free halogen, especially chlorine or chlorine-containing hydrogen chloride gas, can also be allowed to act on the catalyst, simultaneously with, before or after the oxidizing agent. The influence of halogen together with the olefin is admittedly just as possible, however there is to some extent the danger that side reactions, such as a chlorination, will occur. Instead of halogens or halogenated hydrogen to regulate the copper:halogen ratio, other compounds can also be used, which under the reaction conditions give halogen ions such as halogen-oxygen compounds, or also organic substances, e.g. saturated low molecular weight aliphatic halogen compounds such as ethyl chloride. If more halogen is present in the catalyst than corresponds to the copper : halogen ratio of 1:2, the reaction is slowed down. In this case, a part of the halogen ions can be removed by partial neutralization, precipitation or with the help of anion exchangers. But you can also wait until the formed volatile halogen-containing by-products have carried out so much halogen that the optimum ratio is again present.

The necessary amount of halogen compounds, which in the simplest case is to be understood as hydrochloric acid, which is necessary to set the proposed optimum ratio, can be easily calculated and checked by periodic analysis. Thereby, the copper analysis only needs to be carried out occasionally, because the copper content in the solution or the catalyst sludge, can hardly be changed. It is therefore sufficient if periodic chlorine analysis is carried out, preferably according to the usual rapid method.

If, with a newly installed catalyst, the optimum ratio of copper to halogen can be set at once, one can from the beginning replace part of the exemplary required copper (II) chloride with copper (I) chloride or with copper acetate and thus achieve that it is obtained already at the beginning high turnover.

The dosing to set the constant ratio between copper and halogen can be carried out continuously or discontinuously. A preferred embodiment consists, for example, of in that aqueous hydrochloric acid is pumped into the catalyst solution with an adjustable dosing pump, or that a few drops of hydrochloric acid are added in smaller increments at certain time intervals.

What determines the speed of the overall reaction is presumably the oxidation of the added Redox system, i.e. for example the oxidation of the intermediately formed copper (I) chloride to copper (II) chloride. Since in order to achieve a higher turnover it is advantageous to speed up the slowest reaction, in this case provision must be made for a faster oxidation of the Redox system by an oxidizing agent such as oxygen or oxygen-containing gases, preferably air. This can be achieved by a finer distribution of the oxidizing gases which belong to the state of the art, or by working with elevated oxygen partial pressure, or by adding inorganic oxidation accelerators.

Furthermore, it was found that a surprising increase in the reaction rate and an increase in the olefin conversion can be achieved, resp. — at the same turnover — a significant increase of it per time unit through flowing reaction participants, if the reaction is carried out in the presence of Redox systems, especially of an inorganic nature and of quinones which have possibly been made water-soluble by substitution with sulfo- and/or carboxyl groups. These aforementioned quinones resp. their substitution products or their water-soluble salts make the oxygen's transition from the gas phase to the liquid phase easier.

As quinones, o- and p-quinone can be used, for example, as possibly alkyl-

learned benzoquinones, naphthoquinones, anthraquinones, phenanthrenequinones or their above substitution products. You get

for example, by adding 1,2-naphtho-quinone-4-sulphonic acid potassium to a dilute copper chloride catalyst, which is activated with palladium chloride, an increase in turnover of more than double compared to a catalyst without this addition. The used quinones or their sulfones or carboxylic acids or the water-soluble salts of quinone sulfonic or quinone carboxylic acids are suitably added in amounts of up to 10 wt. of the amount of the catalyst, preferably in amounts from 0.1 to 3 per cent.

to the catalyst. If the oxidation is carried out in two steps, as was further described above, then before or during the catalyst's oxidation, hydroquinones can also be added which correspond to the quinones or

quinone compounds and which are thus oxidized to the quinones.

By the additional use of the mentioned quinones resp. their derivatives it is possible to

reduce the amount of catalyst active

substances in the catalyst. This enables a reduction in catalyst costs and also a reduction in the formation of by-products.

As was further found, the present reaction was also favorably influenced by high-energy radiation, preferably by ultraviolet light, above all if oxygen is used as an oxidizing agent. The impact of this radiation, which can also be used in the form of X-rays, activates the oxygen in particular and increases its oxidation activity, as both the actual reaction with the olefin, as well as any necessary oxidative destruction of the by-products, e.g. of oxalic acid is promoted. With the help of these precautions, the turnover is increased, the formation of by-products is reduced, and thus the lifetime of the catalyst is significantly extended, whose activity can otherwise decline after a longer period of operation.

In practice, a mercury-quartz lamp is advantageously used as a radiation source, which is built into a catalyst so that the light energy can be utilized as widely as possible. If you work with a plant to which the oxygen or the oxygen-containing gases are introduced separately from the olefin or the olefin-containing gases or also an olefin-oxygen mixture, it is advantageous to build in the radiation source near the oxygen inlet, so that the oxygen-rich part is irradiated particularly strongly. This achieves an activation of the oxygen as long as it is still present with a high partial pressure. In the case of an apparatus that works with catalyst circulation, the radiation source can advantageously be built in at the lower end of the catalyst tube, shortly above the oxygen inlet. The activation can also be carried out in such a way that compounds of radioactive elements are also added to the catalyst solution.

In the present method, the reaction is carried out in a homogeneous liquid catalyst solution or with a sludge catalyst. It is known that with a constant volume of the reaction liquid for reactions that do not proceed completely in one direction, the greater turnover is obtained if the reactor is built as tall and narrow as possible. Furthermore, it is obvious that such a reaction proceeds all the better the finer the aerated components are distributed in the liquid. The suitable catalyst solutions for the process according to the invention now sometimes have the property of foaming after some time. On the one hand, it is beneficial for the reaction, because a fine distribution of the gas in the contact liquid is achieved, and sometimes you can even intentionally add foam-forming substances to the liquid. On the other hand, however, the foaming means that the available reaction space is only used insufficiently, as only part of the catalyst solution is in the reactor in foam form. The rest, on the other hand, collects, for example, in a broadly designed calming zone and becomes more or less inert to it per time unit gas flowing through.

This disadvantage, which becomes increasingly greater with increasing gas supply density, can now be avoided if the catalyst liquid, which has been conveyed through the gaseous reactants at the head of the reactor, passes through a calming zone and is then reintroduced at the bottom of the reactor. The removal of the liquid from the top of the reactor and the introduction again at the bottom can, for example, take place with the help of a pump system, or also solely by gravity, as the added gases take over the material transport from the bottom of the reactor to its top. The yields of aldehydes or ketones in this circuit method with the same amounts of precious metal inserted in the solution more favorably than in the method without a circuit. In example 59, a corresponding search is described.

In addition, all difficulties with the procedure which are to be returned to the foaming are eliminated.

A further advantage of this recirculation method consists in the fact that one can send part or all of the catalyst liquid, which flows back, from the top of the reactor in an expulsion column and remove dissolved or liquid reaction products in whole or in part. In this way, as mentioned above, the formation of by-products can be reduced, for example in this way the content of acetic acid is kept low. The expulsion can be e.g. either carry out by heating the liquid higher, or with the help of inert gases such as water vapor or nitrogen. By this expulsion of all or only part of the reaction product, this avoids a further impact and change by the oxidizing agent. The expulsion column can, for example, be designed exactly as the reactor itself. Here, too, a cycle of the catalyst solution can be achieved with the help of the expelling gases or steam. In the same way, the catalyst liquid allows itself, by separate reaction of the olefin and the oxygen, as described above, possibly after it has passed the expelling column to also be brought into the regenerator from whose calming zone it runs back into the reactor. In this case, the regeneration and expulsion can also be carried out at the same time with one and the same gas or gas mixture, e.g. by a mixture of oxygen with nitrogen and/or with water vapour. By utilizing the force of gravity and the transport effect of the gas that is sent through, the use of the pump is not necessary.

In many cases, it is also advantageous to carry out the conversion in a method known per se, namely in a pipe, through which the catalyst liquid or sludge catalyst and the reaction gas mixture flow at high speed. This brings with it considerable advantages, as not only is a clear increase in turnover achieved, but there are also significantly fewer by-products. This effect is particularly evident when carrying out the reaction under elevated pressure. For example, a pressure of up to 100 ato can be used below, as the reaction gas is added under a correspondingly high pressure. However, this embodiment can also be carried out at normal or reduced pressure. Preferably, the catalyst liquid is led with the gas in turbulent flows through the appropriate horizontal, but possibly also differently, for example inclined or upwardly arranged pipes, which consist of e.g. of titanium or titanium alloy rings, for example those containing at least 40 per cent titanium, or tubes lined with this. However, one can optionally also use a lower flow rate than is necessary to achieve a turbulent flow. In order to favor a turbulent movement, you can also place filler cells or built-ins in the pipe. Furthermore, the tube can also be designed meander-like. Finally, the reaction participants can also be added, in addition to relatively inert gases such as carbon dioxide, nitrogen, gaseous saturated hydrocarbons such as methane or ethane, hydrogen and the like. whereby possibly the turbulence can be increased.

In addition, it was found, which is particularly important when carrying out the method with separate reaction and regeneration, that a disturbing precipitation of solids, which has been observed from time to time in other embodiments of the method, does not occur. If the method is carried out in a reaction and a separate regeneration step, one or both of these steps can be carried out in the flow tube. Hereby, it is also possible to carry out the reaction and regeneration of the contact under different pressures and/or temperatures. This can be significant for that reason, because the solubility of olefins and oxygen in the catalyst solution is different and in particular the regeneration that takes place during oxygen consumption is favored by the application of pressure and temperature - increase.

Of course, the present method can not only be carried out in flow pipes but also in desired other known devices. For example, a vertical tube, which is equipped with a sintering plate (Fritte) or a rotating stirrer, can be used as a reaction vessel. The method can also be carried out in ordinary reaction towers, e.g. in sprinkler towers, which are best filled with overflow containers. The gas can, for example, be injected through sintered glass masses, or lead in in another way, and optionally divide too large gas bubbles into smaller ones, e.g. using stirrers. Vibro mixers, turbo mixers and the like are also suitable. Of course, the reaction can also be carried out continuously in these different embodiments.

The turnover and the space-time yield depend significantly on the fine distribution of the gas, the residence time and composition of the catalyst liquid, the temperature and the pressure. The most favorable residence time can be brought to light by professionals in the area in a simple way.

Furthermore, it is not necessary for the catalysts to be produced from fine chemicals, on the contrary, they can also be produced from the corresponding metals of technical purity. Such metals as copper and iron can also be easily brought into solution by non-oxidizing acids, such as hydrochloric acid and acetic acid, where an oxidizing agent is optionally added during the dissolution of copper, or during the dissolution process a gaseous oxidizing agent such as oxygen or air enriched with oxygen. The impurities contained in the technically pure metals do not interfere if the solutions are later used as catalysts for the olefin oxidation. In particular, small amounts of foreign metals, which can be contained in technically pure copper or iron, are practically not detrimental to the catalyst action. Anion formers contained in the metals, such as sulphur, phosphorus, carbon, silicon, etc. transferred by dissolution either in hydrogen compounds, e.g. in H2S that escapes with the exhaust gases, or is oxidized to acids of a higher rank, e.g. H2S04, which does not interfere, or is finally partially transferred into soluble compounds, e.g. CuS, which only appears in small amounts and if necessary can be easily removed, e.g. by filtration before the further use of the catalyst.

The solutions obtained in this way can then, after adding the noble metal compounds, be used, possibly after diluting with water and setting the hydrogen ion concentration to the desired value, directly as a catalyst for the olefin oxidation in the liquid phase.

Acids for dissolving the metals are mainly hydrochloric acid and acetic acid, as the presence of these acids is particularly advantageous in the oxidation of olefins to aldehydes, ketones and acids. But you can of course also dissolve in other acids, e.g. nitric acid, and use the solution obtained in this way — suitably after removing the excess acid to adjust to the desired pH — possibly after partial transfer into chlorides or acetates as catalysts.

Furthermore, it is not necessary to add palladium chloride directly, on the contrary, palladium metal can also be used appropriately in fine distribution. In the course of the reaction, this turns into palladium chloride or other palladium compounds.

For example, the catalysts as anions may contain chlorine ions or other halogen ions such as fluoride or bromine ions, nitrates or chlorate, perchlorate residues and the like, or mixtures of such anions with e.g. sulfate or acetate residues. A content of perchlorates is sometimes of particular advantage.

Although the catalysts usually have a good activity even after a longer reaction time, especially if anions are added during the reaction, it may be appropriate to provide for regeneration from time to time. Also for this, some embodiments will be described in the following: It may happen that the catalysts during very long operating times lose a more or less large part of their activity due to — even in small quantities — formed by-products or introduced foreign substances. The formed by-products consist for a part of at least to a certain extent water-soluble organic compounds such as acetic acid, oxalic acid, higher aldehydes or ketones, or chlorinated organic compounds. Due to these by-products, precipitation may also occur, e.g. of heavy metal oxalates. Some intruded foreign substances can, e.g. originate from the contamination of the gases or from the corrosion of apparatus parts, for example from the iron parts, or from the reactor lining.

The catalysts can now be easily freed from the contaminants and thus regenerated if, under the exclusion of significant amounts of oxygen, by the influence of carbon oxide, olefin, e.g. ethylene, or hydrogen or a desired mixture of two or three of these components, precipitates the present copper (H) chloride as copper (I) chloride and precipitates the noble metal compound as elemental metal. The mixture of copper (I) chloride and noble metal is suitably washed, water and acid are added, suitable hydrogen chloride, possibly in the form of hydrochloric acid and can in this form, or better after oxidation with oxygen or oxygen-containing gases such as air, be used again for the reaction. If one renounces a separate oxidation and allows the olefin and oxidizing agent to act at the same time, this is effected during the subsequent reaction by oxidizing agents, especially oxygen which is present in the reaction gas. Optionally, after returning the regenerated but not yet oxidized catalyst, the amount of oxygen in the reaction gas can also be temporarily increased. If the catalyst's reduction does not exclude the oxygen completely, the use of a slightly larger amount of reducing agent is absolutely necessary.

This design is of particular importance in the case of catalysts which, in addition to the precious metal, mainly also contain significant amounts of copper salts, as both of these rather expensive components of the contact — CuCl and precious metal — fall out, while the other impurities resp. the additions, e.g. iron salts remain in the solution and are thus separated from the catalyst-active substance.

The precious metal is precipitated quantitatively.

CuCl also completely precipitates, except for a small amount which is soluble in water. Therefore, when reinserting the catalyst, the corresponding amount of fresh CuCl2 and/or CuCl + HC1 is appropriately added. If the catalyst also contains further additives such as iron salts, these, mostly cheap substances, can also be supplemented again.

The impact of CO and/or olefins and/or H2 takes place in the simplest way when introduced into the catalyst solution. In most cases, normal conditions are sufficient, however, working at elevated temperature and/or elevated pressure can also be advantageous. Especially when using water, which has the weakest reducing effect of the substances mentioned, stricter conditions may be in order. When using olefins as a reducing agent, the oxidation power of the catalyst can also be utilized for the further formation of aldehydes, ketones and acids.

Furthermore, it is important before the impact of the aforementioned gases by neutralization or buffering to completely or partially neutralize or debuff the acid present, because the reaction proceeds too slowly at too high an acidity and does not proceed completely either. In addition, CuCl is also noticeably soluble in concentrated hydrochloric acid, whereby copper loss can occur. Thereby, account must be taken of the fact that also during the reduction of copper or the precious metal chloride, hydrochloric acid is also produced, which may also have to be neutralized or debuffered in addition. However, a weak acidity is of no importance for the precipitation.

The neutralization or debuffering can be carried out in the usual way with alkaline reacting substances such as sodium lye, soda ash, sodium acetate, lime, chalk and similar compounds. The reducing gases can be cycled for reasons of economy, as when using CO, possibly also a CO2 scrubber, can be switched between them.

If larger amounts of catalyst are used, it is advantageous to always only regenerate a small part of the catalyst and then add it to the main amount in order to avoid operational disturbances. Of course, both catalysts, which are used by the simultaneous action of olefins and oxygen, and those used by the separate action of oxygen and olefins can be regenerated in this way.

Furthermore, not only liquid catalysts can be regenerated in this way, but also catalysts with a solid layer, e.g. by releasing the catalytic compound from the carrier, or by carrying out the precipitation directly on the carrier.

One possibility, in particular to recover the palladium metal from the catalyst, consists in allowing acetylene to act on it in a manner known per se in a strongly acidic medium. Thereby, a palladium acetylene compound precipitates which can be easily separated and freed from other cations and also from anions by washing with water. This palladium acetylene compound can then be transferred into palladium oxide in the air, or possibly also in the presence of ammonium nitrate and again transferred directly into the chloride with hydrochloric acid. It is an advantage of this working method that the effect of acetylene on the palladium compounds can also be carried out in the presence of oxygen.

Another possibility for the regeneration of such catalyst systems, whereby the oxidation is carried out in the presence of liquid, consists in removing the by-products formed oxidatively by means of nitrogen-oxygen compounds such as nitric acid or nitrous gases, or by the influence of halogen, above all chlorine or N-O halides such as NOC1. Mixtures of these oxidizing agents can also be used in the same way.

Furthermore, the oxidizing agent, e.g. nitrosyl chloride, also first formed during the reaction. The aim of this method of working is not the oxidation of the reduced step of the added Redox system — although this naturally also takes place at the same time — but a far-reaching destruction of heavy or non-volatile by-products, as much as possible into acetic acid or into carbon dioxide.

The reaction can be accelerated by simultaneous exposure to high-energy radiation, e.g. of ultraviolet light, which is particularly important when working with relatively low temperatures, e.g. between 90 and 150° C. It is advantageous to irradiate under the influence of the oxidizing agent with a mercury-quartz lamp.

Optionally, you can also vary

this method of working with simultaneous additional use of oxygen or air, e.g. by blowing these gases into nitric acid, or using mixtures of chlorine and resp. or nitrous gases with oxygen or air.

The destruction of the by-products can take place in a simple way by heating the catalyst or some precipitated and separated precipitation with the oxidizing agent, the amount of which must be chosen according to the amount of substances to be oxidized and which preferably, however, constitutes 2-50 percent of the catalyst amount. In order to achieve a sufficient reaction rate, the working temperature is conveniently in the range from 90-250°C, however, it can also be higher or lower as it is advantageous to work under pressure. After complete oxidation, it is advantageous, however not absolutely necessary, to remove the N-O compounds or chlorine. This can happen by blowing out with inert gases or with oxygen or air. You can also evaporate the catalyst solution to dryness and then top up to the original amount with water or water-containing solvents.

In the oxidation with nitric acid or with nitrous gases, relatively insoluble metal oxide salts can easily form, e.g. copper oxide chloride, especially in case of chlorine ion deficiency. It may therefore be appropriate, after the removal of the N-O compounds by hydrochloric acid addition, to set the original or also a randomly desired halogen, e.g. chlorine ion concentration. This is particularly recommended if the processed contact was freed from nitric acid and nitrous gases by evaporation. When using chlorine or mixtures of chlorine and N-O compounds as an oxidizing agent, the working method can be adapted so that the supplementary setting of the desired chlorine ion concentration is made redundant.

A further possibility of regeneration is also important with such catalysts where liquids are present, i.e. as well as with those where work is done in a purely liquid phase as well as with those where there are also solid bodies, catalysts, or also adsorption agents, such as activated charcoal.

Furthermore, it applies in particular to such catalysts which contain iron and/or copper and compounds of noble metals from the 8th group and which have lost activity due to precipitation of insoluble compounds, e.g. in the form of oxalates and/or iron oxide hydrate. These precipitates can now — possibly after a thermal treatment — be taken up in mineral acid, suitably hydrohalic acid, such as hydrochloric acid and then again added to the contact. With this precaution, the contact's activity can be brought back up to its original height, so that work without disturbances is possible over a longer period of time.

If copper is present, copper oxalate usually also precipitates. In this case, it has proven appropriate to treat the precipitate first thermally at relatively low temperatures, e.g. 200-500°C, and to take up the resulting residue in mineral acid, preferably in hydrochloric acid under the introduction of oxygen or air, or in nitric acid, or in mixtures of hydrochloric and nitric acid, and add the resulting solution back to the catalyst . In order to avoid excessively strong acidification of the catalyst, the obtained residue is appropriately taken up in the least amount of acid possible, i.e. approximately the calculated amount or a small excess.

If significant amounts of iron are present, it is necessary to carry out any thermal treatment only at such temperatures, whereby the iron oxide does not yet become insoluble. Alternatively, the thermal treatment can also be combined with the acid treatment in such a way that the acid is allowed to act at elevated temperatures, e.g. above 100°C, and also allows high-energy radiation, e.g. ultraviolet light affects the destruction of any oxalate present.

If copper and iron are present in the precipitate, one can also first dissolve soluble components present in the precipitate with mineral acid and as described above, anneal the remainder and dissolve the residue in acid also as described above.

When using nitric acid as mineral acid, it may also be appropriate to add hydrochloric acid to the solution obtained in this way, in order to regulate the chlorine ion concentration in the catalyst solution.

Both of the last described embodiments for the regeneration by treatment using nitrous gases and similar resp. mineral acids, can take place at specific time intervals as periodically as possible, or also continuously, e.g. in such a way that you always only treat a small removed part of the catalyst, or a branched by-stream, which you subsequently add back to the main quantity. The regenerated solution can optionally be modified by adding catalyst-active resp. catalyst-activating substances, which are further described above, e.g. salts of haloacetic acids or quinones optionally substituted by sulfonic or carboxylic acid groups or their salts.

To avoid corrosion of the equipment, it is often appropriate to use devices lined with titanium or titanium alloys, e.g. with those containing 30 per cent titanium or more, or which are also lined with tantalum. However, glass shards or enamelled or rubberized vessels can occasionally also be used. Furthermore, the reaction can also be carried out in internally bricked vessels, or under suitable reaction conditions in such vessels which are internally lined with synthetic materials, e.g. polyolefins, polytetrafluoroethylene, or the curable unsaturated polyesters or phenolic, cresol or xylenol-formaldehyde resins. For example, ceramic material with coal stones impregnated with hardenable synthetic resins and similar known materials can be used as internal masonry.

Example 1.

In a reaction vessel with a diameter of 3 cm and a height of 120 cm, you have a solution of 10 g of palladium chloride, 30 g of copper chloride, 20 cm3 of concentrated hydrochloric acid and 200 g of water, to which some caustic soda is optionally added in such an amount that the solution remains acidic. Through a sintered glass mass, one conducts at 90°C per hour in 20 1 ethylene and 10 1 oxygen and occasionally add some more hydrochloric acid. The exiting gases contain approx. 30 puppies. acetaldehyde next to unreacted oxygen and ethylene and can be circulated after separation of the acetaldehyde.

Example 2.

In the same apparatus as in example 1, the following were added: 2 g of palladium chloride, 20 g of copper chloride, 2 g of ferric chloride, 200 g of water, 6 cm 3 of concentrated hydrochloric acid. With the initial addition of 10% caustic soda and the occasional addition of hydrochloric acid, the acetaldehyde content is kept at a level of 20-30 vol.%. by an introduction of 20 1 ethylene and 10 1 oxygen per hour.

Example 3.

Through a liquid column consisting of 10 g PdCI2 + 40 g CuCl2, dissolved in 950 g 65

pst.-ig acetic acid, led per hour 50 1 of a gas mixture, which consists of 66.3 per cent C2H4, 33.2 per cent O2 and 0.5 per cent methyl chloride. Furthermore

the best possible and finest gas distribution is ensured, e.g. by using sintered glass mass, by means of vibromixers, high-speed stirrers, swiveling stirrers or by other known precautions. The contact time can be extended by adding foam-forming substances. The solution is kept at 75-85°C. The escaping gas consists of the unreacted part of the additive gas mixture and the acetaldehyde formed, which can be washed out with water or other known aids. Calculated on converted ethylene, the yield is very high. The conversion depends on the composition of the catalyst solution, the contact time of the gas with the liquid, the pressure and the temperature. Under the stated conditions, for example a very low contact time of only 1-2 seconds, normal pressure and 76°C, the yield amounts to between 5 and 10 per cent, but it can be significantly increased by the aforementioned changes in the reaction conditions.

Example 4.

The solution specified in the previous example is allowed to run in a circuit through a sprinkler tower in which the gas mixture flows towards the liquid. The results are the same as in the previous example, as here too the conversion depends on the catalyst concentration, the contact time, the temperature and the pressure.

Example 5.

At 90 °C, a mixture of 20 l/h ethylene and 10 l /t oxygen. Yield of acetaldehyde calculated on added ethylene initially amounted to 15-20 per cent, after adding a total of 40 cm3 of water in individual portions of 10 cm3 each, it rose to 40-60 per cent.

Example 6.

1 part by weight of palladium chloride and 2-5 parts by weight of CuCl2. 2H2O is dissolved in 50 parts by weight of 65% acetic acid. A solution of a known dispersant resistant to acidic medium, 1 part by weight of an alkylphenyl sulphonate is added. A further addition of a small amount of e.g. 0.2-2 parts by weight two-normal hydrochloric acid can also be beneficial for reducing resp. preventing the excretion of the formed metallic palladium.

Through this solution, at 80-100°C, a mixture of 20 parts by volume of ethylene and 1 part by volume of oxygen was passed, ensuring as fine a distribution of the gas as possible by means of sintered glass mass, high-speed stirrers, rotating stirrers or the like. From the escaping gas, the acetaldehyde formed is absorbed in a washing tower, while the unreacted gas is returned to the circuit. Depending on the amount of liquid column, the gas distribution and the temperature, the ethylene conversion is between 20 and 50 percent. By applying pressure, it can be further increased. The formation of by-products is small. The yield of acetaldehyde calculated on converted ethylene is usually above 90 per cent of the theoretical figure.

Example 7.

1 part by weight palladium chloride and 2-5 parts by weight CuCl,. 2H20 is dissolved in 100 parts by weight of 65% acetic acid. 1-2 parts by weight of activated charcoal in finely powdered form, as well as 0.1 to 0.2 parts by weight of concentrated hydrochloric acid are added to the solution. Additional dispersing agent and/or protective colloids may be added as in example 11. Through this suspension, a mixed gas of ethylene and oxygen in a ratio of 2:1 to 4:1 is passed continuously at 80-100°C, which consists of a mixture of cycle gas and new gas. After passing through a cooler in which the largest part of the entrained water-acetic acid mixture is condensed and from which it then flows back into the reaction vessel, the reaction gas with acetaldehyde, a little water and acetic acid in a washing tower is freed from the reaction product and for the admixtures and possibly returns to the reaction tower after further treatment. From the washing liquid

the acetaldehyde is obtained by distillation in a yield between 30 and 40 per cent calculated on the permeated olefin or 90 per cent calculated on the converted ethylene.

Example 8.

In a vertical reaction tube there is a solution of 2 g PdCl2, 10 g CuCl2. 2H20 and 1 cm3 of concentrated hydrochloric acid in 100 cm3 of water. The solution has a pH of approx. 1. Through the contact solution, at a temperature of 70°C, 10 1 ethylene and 5 1 oxygen per hour. The acetaldehyde formed is obtained by washing the exiting gas mixture with water. The turnover amounted to approx. 30 percent

Example 9.

250 cm3 of aqueous contact solution containing 5 g PdCl2, 25 g CuCl2 is filled into a pressure apparatus. 2H20 and 2 ems concentrated hydrochloric acid and which has a pH of approx. 1. At a bath temperature of 75-80 °C, introduce 15 1 ethylene and 5 1 oxygen per hour with a profit of 3 ato. The turnover calculated for ethylene is 40-50 per cent.

Example 10.

In a vertical reaction tube with sintered glass mass, there is a catalyst solution consisting of 1 g of rhodium chloride and 75 g of CuCl2. 2H20 in 1 liter of H20. The pH of the solution was adjusted to 1.5 with hydrochloric acid. Through this solution, at 80 °C, 20 1 ethylene and 10 1 oxygen per hour. The acetaldehyde formed can be washed out with water from the exhaust gas. The turnover calculated on added ethylene amounts to approx. 15 per cent, but can be increased by applying pressure. Under the same conditions, similar results can be obtained by using iridium chloride or ruthenium chloride instead of rhodium chloride.

Example 11.

It is precipitated in an aqueous solution in the presence of 10 parts by weight of coal powder in a known manner, i.e. by means of formaldehyde or another reducing agent and lye, optionally in the presence of a protective colloid from 1.5 parts by weight of palladium chloride approx. 0.9 parts by weight of metallic palladium. The palladium-charcoal suspension is sucked off, washed neutral and suspended in 1500 parts by weight of water. One leads through this suspension at approx. 80°C a mixture of 2 volumes of ethylene and 1 volume of oxygen in finely divided form, small amounts of aldehyde can be detected in the exhaust gas after a short time. If a further 200 parts by weight of copper chloride are added to this suspension, the yield of acetaldehyde rises within a few hours to 20-25 per cent of the theoretical amount, calculated on the ethylene used.

Example 12.

In 160 ml of a catalyst solution, which per 1 contains 12.5 g of PdCl2 and CuCl2. 2H20, is conducted at 70°C per hour into 10 1 of a gas mixture consisting of 4 parts by volume of ethylene and 1 part by volume of oxygen which is finely divided by means of a sintered glass mass. It is formed per hour 1.0 g acetaldehyde. If, in addition, per hour, 10 ml of 10% hydrogen peroxide is dripped into the contact solution, then the acetaldehyde yield doubles. Without the introduction of oxygen, the oxidation can also be kept going only with hydrogen peroxide, but then with less turnover.

Example 13.

Through 100 ml of a solution, which per 1 contains 2 g PdCl2, 10 g CuCl2 . 2H.0 and 5 ml concentrated hydrochloric acid, at a temperature of 68-70°C a mixture of 2 1 ethylene and 1 1 oxygen is passed through per hour. The pressure in the apparatus is kept below 300-320 mm Hg. The conversion to acetaldehyde calculated on ethylene input amounts to approx.

20 percent

Example 14.

In a 12 m high pressure apparatus with catalyst circulation and a reaction volume of 1 m3, 800 1 of a catalyst solution containing 5 g PdCl2, 50 g CuCl2 in 1 1 water is filled. 2H2O and 20 g of FeCl.,. With a

excess pressure of 3 ato is directed per hour 160 Nms

reaction gas in. The contact temperature

remains after the beginning without heating at 112-115°C. After washing out the acetaldehyde, the consumed amount of ethylene of approx. 30 Nm3 per hour added and the gas mixture which now contains approx. 92 percent C2H4 and 8 percent O2 introduced at the lowest point in the reactor. The oxygen that is consumed by the reaction and which amounts to approx. 15 Nm3 per hour is separated from the circuit gas, led into the contact bypass line just below the entrance to the reactor. This plant's average output is over 50 kg of acetaldehyde per hour.

Example 15.

A) A catalyst is used which was prepared in the following way: 16.5 g of iron filings were brought into a vertical glass tube provided with a sintered glass mass and heating mantle and poured over with 1000 cm3 of an acid solution containing 135 g of concentrated hydrochloric acid and 76.8 g acetic acid (96 percent) 1 water. During the passage of nitrogen and heating to 80 °C, the iron was dissolved to small residues within 1 to 2 hours, as it could be detected in the exhaust gas alongside a lot of hydrogen, hydrogen sulphide and hydrogen phosphorus. Then 51.7 g of copper shavings were added,

40 ml of concentrated hydrochloric acid added and

the batch gassed with 5 l/hour, after 3

hours with 10 l/hour oxygen. After 12

hours is, apart from a small black precipitate of copper-II sulphide and carbon, all in solution. Small amounts of sulphate ions can be detected in the solution. After the addition of 9 g of palladium chloride, the finished catalyst in the same tube is gassed with 24 1/hour of ethylene and 6 l/hour of oxygen at a temperature of 80°C, whereby after a short initial period a constant 40 percent acetaldehyde could be measured in

the gas.

B) Similar results were obtained if the iron and copper were poured together with the above-mentioned acid solution of acetic acid and concentrated hydrochloric acid, heated under the passage of nitrogen to 80°C, gassed after the first stormy reaction had occurred with 5 1 oxygen per hour after 4 hours with

per hour 10 1 oxygen, and topped up after 12 hours with a further 40 ml of concentrated hydrochloric acid. After another 2 hours, the dissolution process is finished. The solution is clear, of a brown-green colour. A few black flecks of copper-II sulphide floating at the bottom do not interfere.

Example 16.

300 ml of a catalyst solution containing 2 g of PdCl, 50 g of CuCl2 is filled into a tantalum-lined pressure-resistant apparatus which can be heated by means of a heating jacket and in which a sintered glass mass for gas distribution is incorporated. 2H20, 110 g Cu (CH;!COO)2\ H20, 40 g FeCl3 and 40 ml concentrated hydrochloric acid per liters of liquid. Into the reactor is led per hour through the sintered glass mass 20 1 of a gas mixture consisting of 15 per cent oxygen and 85 per cent propylene. At a reactor temperature of 90°C and normal pressure, per hour 5-6 g of oxidation products (essentially acetone alongside a little propionaldehyde). At 90°C and 3 ato pressure, but the same total amount of gas, the yield of oxidation products rises to 8-10 g/hour. If you raise the reactor temperature to 100°C, per hour 15-20 g (peak value to 30 g) oxidation products. Further temperature and pressure increases allow the yields to rise even further, although relatively not as strongly.

Similar results are obtained if the same amount of a catalyst is used

sator resolution, as per liter of liquid, contains 5 g PdCl2, 50 g CuCl2 . 2H 2 O, 20 g FeCl 2 .

Example 17.

A) 2.0 g PdCl2, 50 g CuCl2 . 2H2O and 110 g of Cu(CH3COO)2. H20 is dissolved with 50 ml of concentrated hydrochloric acid in distilled water (final volume 1000 ml). The solution is filled into a vertical glass tube with a diameter of 3 cm, which at the lower end has a sintered glass mass for gas introduction. The catalyst is heated with a water jacket to 80 °C and thus gassed with a mixture of 40 ml of ethylene per hour and 10 1 oxygen per hour under normal pressure. The turnover of the inserted ethylene amounts to 30 per cent in the first hour (corresponding to 60 per cent calculated on oxygen), but then falls and finally assumes a constant value which, with the occasional addition of small amounts of hydrochloric acid, is maintained over a longer period of time (several hundred hours ). B) The turnover is significantly higher if a similar catalyst is used, which also contains 40 g of FeCl8. C) If you work under the same conditions as before, but instead of 40 g of ferric chloride you add 79 g of green chromium (Ill) chloride, an even higher stationary state is established and even at a turnover of approx. 25-30 per cent calculated on ethylene (equivalent to 50-60 per cent calculated on oxygen) which can be maintained for a longer time by occasional addition of hydrochloric acid. D) If you add 59 g of manganese(II) chloride to the same catalyst instead of iron chloride or chromium (III) chloride and carry out the reaction of ethylene with oxygen under the same conditions, you first get a reaction of approx. 50 per cent of the ethylene (equivalent to 100 per cent

calculated on oxygen and consequently corresponding to the theoretical yield), but the yield falls slowly and finally settles at a constant value of likewise 25-30 per cent calculated on ethylene. Corresponding results are obtained if you use the same amount of a catalyst solution as per 1 contains in experiment A 5 g of PdCl2 and 50 g of CuCl2. 2H20 in experiment B also 24 g FeCl3

in experiment C instead of FeCl3 40 g green chromium chloride and in experiment D instead of FeCl3 and chromium chloride 30 g manganese (II) chloride.

Example 18.

A catalyst solution was prepared from 5 g of PdCl2, 34 g of CuCl2. 2H 2 O, 50 g of copper acetate — H 2 O and 73 g of cerium III chloride, as well as 30 ml of concentrated hydrochloric acid and making up with water to 1 liter were gassed in a sintered glass tube to the gas inlet at 80°C with 40 1 of ethylene per hour and 10 1 oxygen per hour. The conversion of the added ethylene to acetaldehyde amounts to 25 per cent, corresponding to 50 per cent calculated on oxygen.

Example 19.

5 g PdCl 2 , 17 g CuCl 2 . 2H2O, 24 g FeCl3, 70 g Cu acetate. HpO, 40 ems concentrated nitric acid, 500 cm^ of water are filled in a glass tube with sintered glass mass and it becomes per hour preceded by 30 1 of a gas with 82 per cent ethylene and 18 per cent oxygen at 90°C and normal pressure. You get 15 g of acetaldehyde per hour. The contact retains this performance if its activity is maintained by continuous addition of hydrochloric acid.

Example 20.

5 g PdCl 2 , 17 g CuCl 2 . 2H2O, 60 g Fe (NO.,),, . 9H20", 70 g Cu acetate. H20, 35 cm3 concentrated HC1 and 500 ems H20 are gassed through at 2 ato and 110°C in a pressure apparatus of the same measurement as in previous examples with 60 Nl/hour of a mixture of 15 percent .02 and 85 percent ethylene.You get 40 g of acetaldehyde per hour.

Example 21.

3 g Pd nitrate, 50 g Cu (N03)2 . 3H20, 500 ems H20 is filled in the apparatus of the preceding example. It is gassed through with 30 1 per hour of a mixture of 65 percent ethylene and 35 percent oxygen. The reaction temperature is at 90°C. The gas leaving the reactor contains 20% vol. acetaldehyde.

Example 22.

A catalyst solution consisting of 1.0 g of PdCl2 and 50 g of CuCl2. 2H 2 O in 1000 ml water was adjusted to a pH of 1.5 with perchloric acid. The solution was filled into a vertical glass tube with a sintered glass mass for gas introduction and gassed through at a temperature of 80°C with a mixture of 20 1 ethylene and 10 1 oxygen per hour. The conversion of the ethylene to acetaldehyde rose rapidly to 20-25 per cent, but fell somewhat after 30 hours, but can be brought back to the old level by the addition of 5 ml of perchloric acid (70 per cent). By occasionally adding more perchloric acid, the turnover was kept constant.

The amount of emerging by-products remained within reasonable limits. If sodium perchlorate and sometimes hydrochloric acid are added to the contact instead of perchloric acid, the same result is achieved.

Example 23.

A solution with 1.0 g PdCl2, 50 g CuCl2 . 2H20 and 5 g potassium chlorate in 1000 ml H20 are gassed through in a tube with sintered glass mass with 20 1 ethylene and 10 1 oxygen per hour at a temperature of 80°C. The conversion of the ethylene to acetaldehyde rises within 2 hours to 40 per cent, then becomes over 100 hours at 20-25 per cent, with small amounts of potassium chlorate and hydrochloric acid being added from time to time. Of the by-products, 1 percent C02 and 1 percent CH3<C>1 were found.

Example 24.

A solution of 3 g of PdCl2 and 63 g of CuBr in 1 liter of water is gassed in a vertical tube at 90-95 °C with a mixture of 20 1 isobueylene and 5 1 oxygen. The exhaust gases are led through cold traps in which isobutylaldehyde and tertiary butanol can be captured as reaction products.

Example 25.

An olefin stream is led over a fan (1) into the reactor (2) or (2a) in co-current or counter-flow with the contact liquid, with a suitable device ensuring a fine distribution of the gas in the contact liquid. Such facilities are, for example, sintered glass mass, mixing nozzles, rotary sieves, vibrators, rapid stirrers or the like.

In this solution, the olefin converts to the carbonyl-containing reaction product. This leaves the reactor together with the unreacted olefin, possibly over a cyclone (3) — and after freeing the reaction product in a separator (4) is separated from excess olefin, which, together with the newly added olefin, is fed over the fan (1) into the circuit of new. The reaction liquid is connected to a de-driver (5) where it is directly or indirectly freed of olefin and reaction product residues with the help of steam. The exhaust gases are possibly supplied to the separator (4). The reaction solution that remains after stripping is now supplied to the regenerator (7) by means of a pump (6) or static gradient, where it comes into intense contact with oxygen or oxygen-containing gases. The regenerator can also be designed in such a way that the contact liquid is fed in counter-current to the oxygen-containing gases. The latter leave the regenerator above the cyclone (8) and can optionally be added to the circuit with the help of a condenser. The contact liquid is supplied via the pump (9) to the reactor (2) or (2a) in a regenerated state. All individual processes can be operated individually or together at increased or reduced or normal pressure.

The method can also be carried out in the same device, if instead of a stream of pure olefin e.g. ethylene in the reactor (2) or (2a) brings into contact with the contact liquid a gas stream containing approx. 7 percent oxygen. Then a catalyst is used which contains 1 kg CuCl2 in 10 1 water. 2H2O, 10 g of PdCl2 and 45 cm3 of concentrated hydrochloric acid. At normal pressure, the reaction temperature is approx. 90°C. In the separation plant (4), the reaction product is naturally separated from excess olefin and oxygen, which, together with new olefin and oxygen in a concentration that corresponds to the conditions stated above, is brought back into the circuit via the condenser (1).

Example 26.

In a reactor there is 500 cm.3 of a catalyst solution containing 50 g of CuCl2. 2H20, 0.5 g PdCl2 and 2.5 cm3 concentrated HC1 and which then has a pH of 1.25. A mixture of approx. 8 1 ethylene and approx. 4 1 oxygen is introduced into the reaction solution at a temperature of 80°C. The reaction solution is kept at a pH of 0.8-1.8. Acetaldehyde is obtained in over 50 per cent yield calculated on the ethylene used.

Example 27.

In a tower with a sintered glass mass or another device suitable for fine gas distribution, there is a solution consisting of 100 parts by weight of CuCl2. 2H20 in 10 times the amount of water, to which 1 part by weight of PdCl2 and 1.1-1.2 parts by weight of 10n-hydrochloric acid have been added. The solution's pH value is between 1 and 2.

A mixture of % ethylene and <1>4 oxygen in finely divided form at 85°C is passed through the solution and the mixed acetaldehyde is washed out from the reaction gas in a known manner.

The turnover depends on the amount of gas rerouted, the gas distribution and the height of the liquid column. It makes up, for example, over a longer period of time 30-35 per cent calculated on the ethylene used. By varying the aforementioned conditions and suitable application of pressure, it can still be significantly increased.

Example 28.

In a pressure apparatus, 250 cm3 of a catalyst solution consisting of 0.25 g of palladium chloride becomes 25 g of CuCl2. 2H20 and 1 cm3 concentrated hydrochloric acid at a bath temperature of 80°C added 10 1 ethylene and 5 1 oxygen per hour. The internal temperature is between 80 and 90°C. Calculated on the inserted ethylene, a yield of over 30 per cent is achieved.

Example 29.

A reaction tube which was kept at 84 °C by boiling 1,2-dichloroethane is coated with 50 parts by volume of a catalyst solution, which in the liter contains 500 g of CuCl2. 2H 2 O (crystallized), 2 g PdCl 2 and 20 ems n-hydrochloric acid. Through a sintered glass mass located at the bottom of the reaction tube, whose supply line for preheating the gas is led from above through the liquid, 2,000 parts per hour of a reaction gas, which consists of oxygen and ethylene in a volume ratio of 1:2, were introduced. 25 percent of the ethylene used was converted to acetylaldehyde in one pass. Within 50 hours, the turnover rose to more than 35 per cent and remained the same during the further term of approx. 30 percent

Example 30.

Through 800 cm3 of an aqueous catalyst solution, which per liter contains 100 g copper chloride and 1.0 g palladium chloride, is passed through per hour 8 1 propylene and 4 1 oxygen. You get 5.0 g of acetone per hour, along with some propionaldehyde. This corresponds to a turnover of 26 per cent of the initial propylene. The residual gas consists of unreacted propylene and oxygen and can be used again.

Example 31.

A catalyst is used which was

produced as follows:

16.5 g of iron filings and 51.7 g of copper filings are dissolved in a large bowl in nitric acid in a fume hood. The solution is evaporated to dryness and washed three times with concentrated hydrochloric acid. 2 g of palladium chloride are then added. The salts are taken up in 80 cm" of concentrated hydrochloric acid, 50 ml of acetic acid are added and diluted with water to 1000 ml. The solution is filled in a vertical glass tube with sintered glass mass as gas inlet and heating jacket, heated to 80 °C and introduced into it 40 1 ethylene and 10 1 oxygen per hour. The acetaldehyde in the exhaust corresponds to a turnover of 35 per cent of the ethylene used.

Example 32.

In a reactor there are 500 ems of a catalyst solution containing 50 g of CuCl2. 2H 2 O, 0.5 g of PdCl, and 2.5 cm 3 of concentrated HCl and having a pH of 1.25. A mixture of approx. 8 1 ethylene and approx. 4 1 oxygen is introduced into the reaction solution at a temperature of 80°C. A high-ohmic, high-temperature-resistant glass electrode and a calomel electrode are built into the reactor and connected to a measuring device. When regulating the ethylene and the amount of oxygen, the pH value is set at 0.8-1.8 and thus a yield of over 50 per cent of acetaldehyde calculated on the ethylene used is obtained in a process without disturbances.

Example 33.

50 ems of a catalyst solution consisting of 1 g of PdCl2, 100 g of CuCl2. 2H20 and 5 ems concentrated hydrochloric acid per 1 liter of water is heated to 80 °C and passed through per hour of 1.5 1 of the reaction gas. The reaction gas consists of 50 per cent ethylene and 50 per cent carbon monoxide and is mixed with half the volume of oxygen before the reaction. The carbonyl compound obtained is washed out. The turnover calculated for used ethylene is over 40 per cent.

Example 34.

Under the same conditions as in example 45, a reaction gas consisting of 10% hydrogen, 20% methane, 35% ethane and 35% ethylene is introduced into the catalyst solution and which before the reaction was mixed with half the volume oxygen. The turnover calculated for the ethylene used is 50 per cent.

Example 35.

Under the same conditions as mentioned in example 45, a reaction gas consisting of 10% hydrogen, 10% carbon monoxide, 30% methane and 50% ethylene is introduced into the catalyst solution and which is mixed with half the volume of oxygen before the reaction . The turnover calculated for the ethylene used is over 40 per cent.

Example 36.

A catalyst solution which has for a long time been used for the oxidation of ethylene to acetaldehyde and which consists of 1 g of PdCl2 and 100 g of CuCl, . 2H20 per liter of water is almost neutralized with caustic soda. Carbon monoxide is filtered and fed into the filtrate at room temperature while excluding significant amounts of oxygen. First white CuCl and then black Pd precipitate. The gas introduction is interrupted when the above liquid has become practically colourless. It is extracted and washed with water. The filtered liquid contains no detectable amounts of palladium. The filtered CuCl — Pd — mixture is slurried with water, the required amount of hydrochloric acid is added, the amount of CuCl2 that has been lost is added and returned to the reactor. Under the standard conditions, after a short initial circulation time with pure oxygen, the mixture works again with the usual turnover.

Example 37.

Under the same conditions as in example 50, ethylene is introduced instead of carbon monoxide. It is also ensured during the introduction by careful addition of caustic soda that the liquid does not become more acidic than pH 3. The acetaldehyde formed from the ethylene during this reaction can be extracted in the usual way.

Example 38.

A catalyst solution containing 1 g of PdCl2 and 100 g of CuCl2 in 1 liter of water. 2H20 is gassed through per hour at 75°C with 20 1 ethylene and 10 1 oxygen. In the course of more than 1,000 hours, you get a turnover of approx. 30 per cent acetaldehyde if it is ensured that the acetic acid formed during the reaction is continuously brought out of the reactor with the water that distils away. In this way, the acetic acid content of the catalyst solution is kept constant at 12-14 per cent. The water that distills off is replaced with new water. Furthermore, the chlorine that is carried away must be replaced by continuous addition of hydrochloric acid.

Example 39.

10 g of PdCl2, 1 kg of CuCl2. 2H20 and 10 1 water are coated at 80°C per hour with 400 1 ethylene-oxygen mixture in the ratio 2:1. During a period of over 1,000 hours per hour 100 g of acetaldehyde next to unreacted starting gas, if one ensures by continuous addition of hydrochloric acid that the molar ratio of Cu ions:Cl ions amounts to 1:1.4 to 1:1.8 and if one simultaneously ensures the removal of the acetic acid that forms, together with the water that distills out of the reaction room.

Example 40.

You work in the same way as stated in example 53 with the difference that you use a contact that contains 10 g of PdCl2, 700 g of CuCl, . 2H.0 and 175 g CuCl in 10 1 water, The turnover is just at the beginning of over 20 per cent. The initially suspended CuCl goes into solution for some time.

Example 41.

In 500 g of water, dissolve 0.5 g of PdCl2, 50 g of CuCl2. 2 H 2 O, and 5 g of 1,2-naphthoquinone-4-sulfonic acid calcium. In a vertical tube, at 75° C, this contact liquid is led per hour 8 1 ethylene and 4 1 oxygen. With continuous distillation of acetic acid, the acetic acid level in the contact is kept low. De-distilled water is replaced with new water. By continuous addition of small amounts of hydrochloric acid, the molar ratio of copper to chlorine is kept at 1:1.4 to 1:1.8. The conversion to acetaldehyde calculated on the ethylene used is approx. 50 per cent. After washing out the acetaldehyde, the residual gas is used again for the reaction.

Example 42.

In 500 g of water dissolve 0.5 g of PdCl2, 50 g of CuCl, . 2 H 2 O and 5 g of anthraquinone-2-sulfonic acid sodium. Otherwise, work is carried out in the same way as stated in example 55. A conversion of ethylene to acetaldehyde of over 30 per cent is obtained.

Example 43.

A) non-circulating catalyst solution. In a vertical reaction tube of 3 m height and 30 mm diameter will be at 80° C a catalyst solution of 1 g of PdCl, and 150 g of CuCl2. 2 H2O in 1 liter of water adjusted to a pH of 1.5 using hydrochloric acid and gassed with 20 1 ethylene and 10 1 oxygen per hour through a sintered glass mass. The foam that forms fills the entire reaction tube and also partially flows over the extended stilling space located at the head of the column. You get a conversion of 30 per cent of the ethylene to acetaldehyde, which can be washed out in the exhaust gas. B) with circulating catalyst solution.

In the same tube as under A), but which is now equipped with a catalyst assembly at the head and a drop line to the foot of the reaction tube, gas is passed through at the same temperature as under A) 3 1 catalyst solution containing 1 g of PdCl2 and 150 g CuCl2, i.e. the same quantities as under A), with ethylene and oxygen (20 : 10 I/hour). The contact resolution moves 1 circuit. The turnover is 35-40 per cent of the ethylene used.

Example 44.

Through a reaction tube of 1 m length and 500 ems content, which is filled with a catalyst solution that per liter contains 1.5 g PdCl,, 100 g CuCl2 . 2 H 2 O and 2 cm^ 10-normal hydrochloric acid are passed a current of 30 1/tme with ethylene. Through the regeneration ration pipe of the same 1 m length and 1000 cm" content and which is filled with the same solution sends but 100 1 air/hour. Both gases are finely divided using a sintered glass mass. Both tubes are provided with extended headers, in which the foam collapses and the gas and liquid separate. By connecting the head of the reaction tower with the lower liquid inlet of the regeneration tower and vice versa, a closed liquid circuit is created so that pumps are not necessary. The rising gas flow puts the liquid into vigorous circulation, which in the present example exceeds 100 l/hour, but which, if desired, can be throttled to, for example, 80 l/hour. The om race can possibly be measured, e.g. by recirculation meter or similar. The towers are heated to approx. 80-85° C. From the exiting gas stream, which is filled with acetaldehyde vapor, the acetaldehyde can be isolated in a manner known per se, e.g. while passing the gas separately through the washing tower. The ethylene can optionally be fed back into the process after branching off a smaller amount of off-gas. Under these conditions, after a certain reaction time, the turnover amounts to between 30 and 40 per cent of the ethylene sent through the reactor. Solid secretions do not occur even after a long operating time.

In the event that there is a fear that the mixture of the remaining air and the acetaldehyde vapor may slightly exceed the lower explosion limit, one can practically place at the head of the regeneration tower well-known safety devices against puffing such as safety discs, flame traps ("Kiestopfe" ) and such. But due to the saturation of the acetaldehyde-air mixture with water vapor and the relatively low oxygen content, which is less than in air, the risk of puffing is very small.

Yields can be increased by applying pressure. Furthermore, the pressure of both gases does not have to be the same if the pressure difference at the building height of the two towers is taken into account. If cooling and/or heating devices are built in, the two towers can also be operated at different temperatures.

Example 45.

A 35 m long vertically arranged several times bent glass tube (the length of a section between two curvatures approx. 1.5 m; the inner diameter of the tube 3 mm) was per hour and at an inlet pressure of 860 mm Hg coated with 40 1 of ethylene and 1.8 of an aqueous contact solution which per 1 contained 0.06 mol of palladium, 1.02 mol of copper, 1.95 mol of chloride ions and 1.5 mol of acetic acid. The reaction temperature was 90-93° C. The catalyst liquid was driven off with the residual gas and the aldehyde isolated from the ethylene by means of washing water. The contact was then regenerated in three consecutively connected cylindrical barrels with each approx. 125 cm» contact content and 10 1 oxygen passage per step and hour at 80° C under normal pressure, so that the color of the contact fluid leaving the regeneration was approximately the same as the color of the original used new contact. From there it was led back to the reaction stage so that a continuous catalyst circuit occurs.

The space-time yield amounted to 60 g of acetaldehyde per hour and liter of reaction space; about. 99 percent of the converted ethylene was converted into acetaldehyde. As by-products, only approx. 0.5 per cent acetic acid and 0.2 per cent carbonic acid, calculated on converted ethylene and precipitation did not occur.

Example 46.

In a similar arrangement as in example 45, under otherwise similar reaction conditions, the catalyst listed there was per. hour treated with 50 1 of a gas mixture consisting of 80 per cent ethylene and 20 per cent oxygen. The catalyst, which contained part of the input gases and the acetaldehyde, was additionally regenerated with 12 1 oxygen per hour at 85° C under normal pressure in a cylindrical vessel that holds 200 cm" contact and the contact is returned to the flow pipe. From the gas mixture leaving the stripping apparatus, the aldehyde was washed out with water and isolated.

The space-time yield amounted to 65 g of acetaldehyde per hour and liter of reaction space, approx. 98.5 percent of the converted ethylene was transferred to 1 acetaldehyde. Furthermore, 0.8 per cent acetic acid and 0.3 per cent carbonic acid were formed as by-products, calculated on converted ethylene. The precipitate could not be seen.

Example 47.

In a 40 m long, meander-shaped horizontally lying titanium tube with an inner diameter of 10 mm, per hour approx. 2 Nm3 of ethylene and 80 1 of an aqueous contact solution containing 0.5% by weight. PdCl2, 33% by weight. CuCl, . 2 H20, 2 wt. Cu(CH 3 COO) 2 . HsO and 3% by weight. acetic acid below 7.5 ato. The reaction temperature is 140° C. The contact was subsequently regenerated in a flow-tube regenerator built analogously to the above-described flow-tube reactor with 2 Nm" of oxygen at 130° C and 6.5 ato and again continuously fed back from there into the flow tube. After reaction and regeneration, the pressure was sometimes removed and both of the unreacted gases, ethylene which had been removed from acetaldehyde with the help of washing water and oxygen, possibly returned to the system at hand.

The space-time yield amounted to 130 g of acetaldehyde per hour and liter of reaction space, approx.

99 percent of the converted ethylene was transferred

in acetaldehyde. Apart from small amounts of acetic acid and carbonic acid, no by-products were observed. Even after longer working hours, no precipitation occurred in the regeneration as well as in the reaction part.

Example 48.

The test device and the catalyst composition in this example are the same as in example 47. 2 Nm3 of a gas mixture consisting of 80 percent propylene and 20 percent propane was per hour fed into the flow reactor under 5 ato pressure at a reaction temperature of 130° C. The catalyst was, after stripping, regenerated in the flow tube regenerator with 2 Nm3 of oxygen per hour at 125° C and 7 ato. The propylene/propane/acetone/propionaldehyde mixture obtained by the reaction was washed with water after the pressure had been removed. The reaction products were isolated.

The space-time yield amounted to 70 g of acetone/propionaldehyde mixture per hour and liter of reaction space (approx. 2 percent propionaldehyde). 98 percent of the converted propylene was transferred in the two carbonyl compounds. Small amounts of chloroacetone and carbonic acid were observed as by-products. Precipitations did not occur.

Example 49.

Through a catalyst which in 1 liter of water contains 1 g of PdCl2, 20 g of trichloroacetic acid and 100 g of CuCl2. 2 H20 was conducted using two third glass masses and at a temperature of 80° C per hour 20 1 ethylene and 10 1 oxygen. The conversion to acetaldehyde, calculated on the ethylene used, amounted after approx. 3 days 40 per cent and can be kept at this size by extra precautions such as addition of HC1, distillation of acetic acid, etc. Precipitations were not observed even with a longer reaction time. After washing out the acetaldehyde, the residual gas is reintroduced to the reaction.

Example 50.

A catalyst is used which is prepared from 20 g of trichloroacetic acid, 7 g of CuC03 to form the copper salt of trichloroacetic acid, 1 g of PdCl2, 90 g of CuCl2. 2 H20 and 1 liter of water. Otherwise, work is carried out as described in example 65. The conversion of ethylene to acetaldehyde amounts to 45 per cent after one day and can be maintained at this level even with a longer reaction time without precipitation occurring, if the working method mentioned in example 49 is observed.

Example 51.

A catalyst containing trichloroacetic acid iron is prepared by dissolving 8 g of FeClg in water, adding ammonia, filtering and washing out Fe(OH)3 and dissolving with a solution of 24 g of trichloroacetic acid, 2 g of PdCl2 and 100 g of CuCl2 . 2 H20 in a liter of water. Per hour, 20 1 ethylene and 5 1 oxygen at 80° C are passed through the contact solution. The conversion to acetaldehyde is 25 per cent calculated on the ethylene used. The turnover could be maintained over a longer period of time without precipitation if the method described in example 49 is followed.

Example 52.

20 g of trichloroacetic acid are dissolved in 245 cm.3 0.5 normal caustic soda, 2 g of PdCl2 and 100 g of CuCl2 are added. 2 H20 and top up with 755 cm3 of water. If one per hour introduces at 80° C 20 1 ethylene and 10 1 oxygen, then a conversion of 45 per cent is achieved if you work under the conditions described in example 49.

Example 53.

If you use the same catalyst as in example 52 and pass, under otherwise identical conditions, a gas mixture of 20 1 ethylene and 5 1 oxygen, which is outside the ignition limit, through the catalyst liquid, you get a conversion of 25 percent without precipitation occurring.

Example 54.

A catalyst solution containing 3 g of PdCl9, 95 g of CuCl2 in 1 liter of water is filled into a 2 m high catalyst tube that has a volume of 1 litre. 2 H 2 O, 64 g Cu(OOCCHs) 2 . H2<0> and 40 g FeCl3."At a working temperature of 80° C, a mixture of 60 1 ethylene and 15 1 oxygen is blown in through a nozzle per hour. The contact, which at room temperature is an almost clear solution, becomes on heating to 80° C yellow-brown due to hydrolyzed ferric chloride. It shows from the beginning strong foam formation, whereby the entire reaction space is filled. The conversion to acetaldehyde calculated on the ethylene used is over 50 percent. The unreacted residual gas is again fed into the reaction.

Example 55.

In a 12 m high catalyst tower with catalyst circulation and a reaction volume of 1 m3, 500 1 of a contact containing 2 g PdCl2, 40 g CuCl2 in 1 liter of water is filled. 2 H 2 O, 60 g CU(COCCH 3 ) 2 . HgO, 25 g FeCl3 and 20 ml concentrated hydrochloric acid. The catalyst is completely ready. At a temperature of 85-90° C, one allows per hour 70 ems of a gas mixture containing t 82 per cent ethylene and 18 per cent oxygen flow in through a single pipe. After an initial working time of a few hours, an increasing amount of iron hydroxide sludge 1 occurs in the contact, which can be stopped or also reduced by adding hydrochloric acid. The average performance of such a contact amounts to 20 kg of acetaldehyde per hour.

Example 56.

If one works in the same apparatus with the same catalyst and with the same gas mixture as in example 71 and a gas pressure of 3 ato at the bottom and 2 ato at the top of the contact tube, it is possible per hour produce up to 100 kg of acetaldehyde at a temperature of approx. 105° C and a gas supply of 160 ms per hour. If one ensures the constant presence of a contact sludge.

Example 57.

700 parts by volume (parts by volume relate here to parts by weight such as cm3 to grams) of a catalyst solution with 1 g per liter of palladium, 0.2 mol/l iron, 0.8 mol/l copper and 1.0 mol/l chlorine as well as 1 mol/l acetic acid are brought at 2 ato and 105—115° C per hour in contact with 200,000 parts by volume — measured under normal pressure at 0° C — ethylene-oxygen in a catalyst tower. The yield of acetaldehyde initially amounts to 80 parts by weight per hour and after 2 days 100 parts by weight per hour. After 8 days, the yield drops despite the addition of hydrochloric acid. The contact contains practically no more dissolved iron. As a result, the iron hydroxide that precipitates is isolated and brought into solution with the required amount of concentrated hydrochloric acid and added to the contact again. You then get back the original yield of 80 parts by weight per hour.

Example 58.

In the same reaction vessel as in example 73, the same amount of a catalyst solution with the composition 0.05 mol iron/l, 0.8 mol/cup, 1.7 mol Cl/l and 1 g Pd/l per . hour in contact with 200,000 parts by volume of an olefin (ethylene-propylene) oxygen mixture, whereby olefin is first present, the residual gas mixture is circulated and, in addition to this, olefin and oxygen are added in a ratio of 2:1. The yield of acetaldehyde and acetone initially amounts to 70 parts by weight per

;ime, after 4 days the yield drops despite :or hydrochloric acid addition. Because of this, the precipitated sludge, which contains 2a, is sol. 10 percent of iron and 90 percent of an organic mushroom salt as well as a copper oxychloride 3g are treated for 5 hours at 250° C until bad organic salts are decomposed. In addition, the residue is brought into solution with just the required amount of concentrated hydrochloric acid and this solution is added back to the Silo remaining contact solution and the original yield of 70 parts by weight is obtained again. hour.

If you remove the sludge continuously by centrifugation or filtration and work it up continuously in the manner described above, a yield of 60 parts by weight can still be maintained. hour.

Example 59.

700 parts by volume of a catalyst solution with 1 g of Pd gr. litre, 52 g Cu/l, 56.8 g chlorine per litre, 60 g acetic acid per liter becomes at 2 ato and 105-115° C per hour brought into contact with 200,000 volume parts (measured under normal conditions) of ethylene and oxygen in a catalyst tower. Dividend amounts per hour 50 parts by weight acetylaldehyde. By continuously sucking off the precipitated copper oxalate and heating it at 280° C in a muffle furnace and again absorbing it with the calculated amount of hydrochloric acid while simultaneously passing oxygen or air and adding it to the contact, the activity of the catalyst is kept constant. If the precipitate is not removed, adding hydrochloric acid cannot prevent the yield from gradually falling.

A catalyst, which also still contains 0.2 mol/l iron, yields 80 parts by weight of acetaldehyde using the same method of operation. If you continuously suck the precipitated copper oxalate and iron hydroxide, heat it at 280°C in a muffle furnace, dissolve it again with the calculated amount of hydrochloric acid and add it to the contact, you can keep the yield at this level for a longer time.

Example 60.

A) A catalyst which in 1 liter of water contains 2 g PdCl2, 120 g CuCl2. 2 H.0, 30 g CufCHjCOCOg . H20 and 20 g FeCl3 and

which had been used for 1,000 hours for the production of acetaldehyde at atmospheric pressure and 80° C from ethylene and oxygen (4:1) finally gave a turnover of barely 20 per cent.

B) 1 liter of the catalyst described under A) which had already been used for 1000 hours was heated with 200 ml of 60% nitric acid for 2 hours on a steam bath and subsequently evaporated to complete dryness while simultaneously introducing air. It is then topped up again with water to 1 liter of liquid and the chlorine ion concentration again brought to the same as the newly prepared output contact using the necessary amount of hydrochloric acid. After a shorter initial operating period, the contact worked under the same conditions as under A) with a turnover of approx. 35 percent C) You work as under B), however with the difference that during the nitric acid oxidation you irradiate with a submerged mercury quartz lamp. The conversion of ethylene to acetaldehyde under the conditions mentioned in example 1 A) then amounts to 35-40 per cent.

Example 61.

1 liter of the catalyst solution from example 60 A) which has been used for 1000 hours is heated with 100 ml of 60% nitric acid for 1 hour in a titanium autoclave at 150-160° C under pressure, so that the nitric acid is still in liquid phase. After this has been taken out of the autoclave, the liquid, as in example 60 B), is evaporated to dryness, filled up with water and the original chlorine ion concentration is adjusted again with hydrochloric acid. The contact then works under the same conditions as in example 76 A) with sales of approx. 40 percent

Example 62.

In a 2 m long reaction tube which is filled with 1 liter of a catalyst solution which contains 3 g of PdCl2, 107 g of CuCl2 in 1 liter of water. 2 H20, 15 g Cu(CH3COO)2". H20 and 12 g FeCl3 and in which the rising gas flow causes a circulation of the contact, 10 1 oxygen per hour is introduced at the lower end and 30 cm above this place is injected 40 1 ethylene per hour through a sintered glass mass. A mercury-quartz lamp is built in between both supply points. During the reaction, it is ensured that the penetration of the rays is not inhibited or restored. The temperature is 80-85° C. Periodically replace the amount of hydrochloric acid consumed, this plant works for a long time completely without disturbances and achieves conversions of 35 per cent acetaldehyde calculated on used ethylene corresponding to 70 per cent calculated on used oxygen, while previously without the use of the mercury-quartz lamp under otherwise similar conditions only a turnover of approx.

30 per cent of the exhaust gas which mainly consists of

of ethylene, but which still contains some oxygen, can, after washing out the acetaldehyde and adding a quantity of ethylene which is as large as the quantities consumed, be added again in the upper supply point, while a quantity of oxygen corresponding to the quantity consumed is supplied through the lower supply part.

Claims (32)

1. Process for the production of aldehydes, ketones or acids corresponding to the aldehydes, by oxidation of olefins in the liquid phase in the presence of water and compounds of noble metals from the 8th group of the periodic table in a neutral to acidic medium, characterized in that the oxidation is carried out by with the help of oxygen, optionally mixed with inert gases, and in the presence of redox systems. 2. Method according to claim 1, characterized in that a copper salt or an iron salt is used as redox system. 3. Method according to claims 1-2, characterized by adding small amounts of active oxidizing agents and resp. or oxidation catalysts. 4. Method according to claims 1-3, characterized in that before or during the reaction, compounds are added which, under the reaction conditions used, give anions. 5. Method according to claims 1-4, characterized in that when using noble metal halides, small amounts of halogen or halogen compounds are added. 6. Method according to claim 1, characterized in that the precious metal is added in metallic form and the higher value steps are produced during the reaction. 7. Method according to claim 2, characterized in that an iron salt is used which is hydrolysed by means of acetic acid or salts thereof. 8. Method according to claim 1, characterized in that the amount of oxygen and/or olefin is varied during the reaction to keep the pH value of the catalytic medium between 0.8 and 3. 9. Method according to claim 1, characterized in that solid bodies which are present in the catalytically active medium during the reaction and which essentially consist of iron, copper and noble metal compounds resp. of the metals or mixtures of these are removed in whole or in part, dissolved in mineral acid, preferably hydrochloric acid, and the resulting solution is then returned to the reaction. 10. Method according to claim 9, characterized in that the removed solid components are heated to such a temperature that no acid-insoluble oxides are formed. 11. Method according to claims 1-10, characterized in that a neutral salt is also present. 12. Method according to claims 1-11, characterized in that the reaction is carried out in the presence of at least one halogen-acetic acid and/or a salt thereof. 13. Method according to claim 12, characterized in that trichloroacetic acid or dibromoacetic acid is used as haloacetic acid. 14. Process according to claims 12-13, characterized in that the halogeno-acetic acids or their salts are used in an amount from 1 to 50 per cent, preferably 20 to 25 per cent, calculated as acid and the percentages are referred to the amount of copper which CuCl2. 2H20. 15 Method according to claim 1, characterized in that molecular oxygen is supplied in such an amount that it constitutes between 8 and 20 volume percent referred to the gas mixture. 16. Method according to claims 1-15, characterized in that reaction products which are dissolved in the catalyst medium are removed from this by stripping, for example with steam. 17. Method according to claim 16, characterized in that it is carried out in a closed circuit consisting of a reactor, regenerator and a stripping device. 18. Method according to claims 1-17, characterized in that the reactor is equipped with a calming zone, for example with an extended vessel at the top. 19. Method according to claims 1-18, characterized in that the catalytically active medium contains a dispersant and/or protective colloids and/or powdered finely divided inert solid. 20. Method according to claims 1-19, characterized in that the total amount of copper and iron compounds in the catalytically active medium is at least 15 parts by weight, preferably 25 to 500 parts by weight per weight part precious metal. 21. Method according to claim 1 to 20, characterized in that the catalytically active medium contains copper and palladium, the copper being present in an amount of at least 15 parts by weight, preferably 50 to 500 parts by weight per part palladium. 22. Method according to claims 1 to 21, characterized in that the olefin is used in the form of a mixture with at least one inert gas. 23. Method according to claims 1-22, characterized in that the olefin is used in the form of a mixture which also contains carbon monoxide and/or hydrogen and possibly other admixtures. 24. Method according to claims 1-23, characterized in that the ratio between copper and the halogen which is not present in the form of neutrally reacting halide is between 1:1 and 1:2. 25. Process according to claims 1-24, characterized in that the reaction is carried out in the presence of a quinone, which is optionally substituted with sulfonic acid groups and/or carboxyl groups, or in the presence of salts of such compounds. 26. Method according to claim 25, characterized in that the compounds mentioned in claim 25 are present in an amount of 0.1 to 3 percent, referred to the catalytically active medium. 27. Method according to claims 1-26, characterized in that the reaction is carried out under the influence of high-energy radiation. 28. Method according to claims 1-23, characterized in that the reaction of the olefin with the catalytically active medium and the regeneration of the catalytically active medium by means of an oxygen-containing gas are carried out in separate pipes and at different pressures. 29. Method according to claims 1-28, characterized in that halides of the polyvalent metals are used as the redox system. 30. Method according to claims 1-29, characterized in that a catalyst is used which contains precious metal compounds and copper compounds and these are regenerated by the action of carbon monoxide and/or an olefin and/or hydrogen and are returned after the addition of mineral acid, preferably hydrochloric acid. 31. Method according to claims 1-5, 23, 28 and 30, characterized in that palladium is regenerated from the catalytically active medium by the action of acetylene, conversion of the acetylene-palladium compound into palladium oxide and return of this oxide as such, or after dissolution in an acid. 32. Method according to claim 1, 23, 28, 31, characterized in that the by-products formed are destroyed by means of nitrogen-oxygen compounds such as nitric acid or nitrous gases, or by effect of halogen or nitrogen-oxygen halides, possibly under the complementary effect of high-energy radiation.