DE1251309B - Process for the revitalization of the aqueous, hydrochloric acid catalyst solution consisting of copper (I) chloride and complexing agents, which was used for the production of acrylonitrile from acetylene and hydrocyanic acid - Google Patents

Description

UNDESREPU BLIK GERMANY

Int. CL:

C 07 c

GERMAN

PATENT OFFICE

EDITORIAL

German class: 12 ο-21

Number: 1 251 309

File number: K 52150IV b / 12 ο

Filing date: February 20, 1964

Open date: October 5, 1967

The invention relates to a method for cleaning and revitalizing the catalyst solution that is used for Production of acrylonitrile or for the joint production of acrylonitrile and monovinylacetylene made of acetylene and hydrocyanic acid. According to the process of the invention, the byproducts in the reaction of acetylene arise with hydrocyanic acid, removed from the catalyst solution or the formation of non-volatile, more soluble organic complexing agent (dissolved resin components) reduced; these are more or less high molecular weight organic compounds that appear as by-products in the reaction of acetylene with hydrocyanic acid arise in the catalyst solution and due to their content of nitrile groups and terminal Carbon triple bonds capable of complexing with copper (I) chloride and therefore in the aqueous catalyst solution are soluble.

The reduction in the formation of non-volatile organic complexing agents is achieved by that a minimum content of potassium chloride of 8 percent by weight, preferably 11 to 13 percent by weight, is maintained in the catalyst solution in the reaction space, the to be added Copper (I) chloride and the precipitated copper (I) chloride are introduced into this catalyst solution only in dissolved form will.

As a measure of the content of non-volatile organic complexing agents in the aqueous catalyst content serves its carbon content. As a result of the measures of the invention mentioned, it occurs a certain carbon content in the catalyst solution, the lower the higher the Potassium chloride level in the catalyst solution is maintained. In addition, the amount of resin is reduced. However, the potassium chloride level in the catalyst solution cannot be set as high as desired, because otherwise the potassium chloride losses in the removal of the ammonium chloride become uneconomically high would.

If the setting of a carbon content lower than 6.5 to 7% is required, then an additional Another measure of the invention carried out, which in the removal of the non-volatile organic Complexing agent by heating the catalyst solution to at least 200 ° C below the temperature adjusting saturated steam pressure and the separation of the resin formed as a second layer.

The progress of the process of the invention is that in the production of acrylonitrile or in the joint production of acrylonitrile and monovinylacetylene in the presence of processes for revitalizing the aqueous,
hydrochloric acid, from copper (I) chloride and
Complexing agents consisting of a catalyst solution used for the production of acrylonitrile
Acetylene and hydrogen cyanide were used

Applicant:

Knapsack Aktiengesellschaft, Huerth-Knapsack

Named as inventor:

Dipl.-Chem. Dr. Kurt Sennewald,

Knapsack near Cologne;

Dipl.-Chem. Dr. Günter Legutke, Brühl;

Dipl.-Chem. Dr. Peter Wirtz, Cologne-Lindenthal - -

Catalyst solutions that are cleaned and revitalized according to the method of the invention, less Resin is formed and thus lower copper chloride and yield losses occur than after the known ones Procedure. The measures of the invention are based on the knowledge that the resin formation is dependent

a) the carbon content of the catalyst solution,

b) the potassium chloride content of the catalyst solution and

c) the addition of the copper (I) chloride that has not been complexed.

Furthermore, the process of the invention allows the after the catalyst revitalization known processes to maintain adjustable high catalyst performances over any length of time.

The German patent specification 1 212 516 already describes a process for the production of acrylonitrile from acetylene and hydrocyanic acid in aqueous, copper (I) salts and potassium chloride or ammonium chloride as Complexing agent-containing catalyst solutions described, with one to maintain the constant catalyst performance during the course of the reaction in the catalyst solution a molar ratio from copper (I) chloride to the amount of potassium chloride, ammonium chloride, cyanions and the resulting nitriles as complexing agents equal at least 1: 1 to preferably 1: 0.8, simultaneously a free hydrochloric acid content of about 0.2 to 3.5 percent by weight and a cyanide content from about 0.35 to 1.6 percent by weight, each

709 650/423

moved to the total amount of the catalyst solution, as well as a certain density of the catalyst solution maintains.

A similar method is described in German patent specification 1211 159, but with the Molar ratio of copper ions to the amount of all complexing agents (including copper (I) chloride itself) is 1: 1.8 to 1: 1.5. This can be achieved, among other things, by part of the Catalyst solution that contains unconverted hydrocyanic acid and / or unconverted acetylene, circulates over solid copper (I) chloride.

Finally, it is stated in German Patent 1,215,140 that this can be achieved in the resinous Copper (I) chloride containing impurities with alkali chloride solutions or hydrochloric acid in the case of increased Extract temperature and the extract immediately of the catalyst solution for the production of the acrylonitrile can feed again.

It should already be noted that the described process features of the German patent specifications 1 212 516, 1 211 159 and 1 215 140 are also applicable to the method of the invention. The measures of the invention can thus additionally with the measures of the method of these patents can be applied.

In the German Auslegeschrift 1 090 195, in which a process for the simultaneous production of Acrylonitrile, monovinylacetylene and acetaldehyde is described, it is already pointed out that the decrease in the performance of the catalytic converter is caused by the presence of hydrocyanic acid, which promotes the formation of additional complexing agents for copper (I) chloride. This fact is in the German patent 1 212 516 explained in detail and theoretically interpreted.

The removal of the soluble, non-volatile organic complexing agents from the catalyst solution takes place according to the German Auslegeschrift 1 011 876 by partial precipitation with water with the addition of a Agent releasing chlorine ions, whereby the resin dissolved by complex formation precipitates, the main amount Copper (I) chloride, however, remains dissolved. The disadvantage of this method is that it is large Amounts of copper (I) chloride can also precipitate and be lost or that the catalyst performance is greatly reduced when ammonium chloride solution is added will.

Assumes the German Auslegeschrift 1 011 876 that the tarry components are water-insoluble, so In German Auslegeschrift 1 124 480 it is assumed that the tarry components are water soluble. The method is based on the removal of tarry By-products from aqueous, hydrochloric acid copper (I) chloride solutions by making the Catalyst solution, which contains 5 to 25 percent by weight tar, diluted with 5 to 10 parts of water, whereby the copper precipitates as copper (I) chloride, while the tarry components remain in solution. This Contradiction shows the disadvantages of the two methods mentioned. Part of the non-volatile organic Complexing agent is water-soluble due to its content of hydrophilic groups, the other part is water-insoluble, unless it is kept in a complex solution in concentrated copper (I) chloride solution. It therefore depends on the type of catalyst, whether one or the other part predominates. Is z. B. only Acrylic acid nitrile produced with excess hydrogen cyanide in the presence of an acidic catalyst solution, so the water-soluble part predominates. With the simultaneous production of acrylonitrile and monovinylacetylene with a deficit of hydrocyanic acid, the water-insoluble portion predominates. These disadvantages of the processes mentioned, which depend on the solubility behavior of the organic complexing agents exist, do not occur in the method of the invention.

The method of thermal resuscitation according to the method of U.S. Patent 2,632,737 consists in evaporating the catalyst solution to dryness, smoking off the ammonium chloride formed and burn all organic matter; it has the major disadvantage that a Part of the copper (I) chloride is oxidized and must be reduced before reuse. traces of copper (I) chloride are in the joint representation of acrylonitrile and monovinylacetylene undesirable because they favor the formation of dichloroethylene. Besides, the thermal Revitalization is technically complex, since it is usually carried out in a rotary kiln, the heat of evaporation of the water has to be applied and corresponding Waste gas scrubbing must be used in order to avoid losses through sublimation of the copper (I) chloride and to wash the hydrochloric acid-containing exhaust gases neutral.

Finally, in the German patent specification 869 948, a method for reviving the for Production of vinyl acetylene from acetylene used as a catalyst copper (I) chloride solutions described, which is characterized in that the catalyst solution with concentrated hydrochloric acid heated to about 70 to 80 ° C. Since the catalyst in this process does not work with hydrogen cyanide at all Comes into contact, it contains other impurities that require other resuscitation methods, which are of course different from those of the invention.

The removal of the non-volatile soluble organic complexing agents by the process of Invention is technically particularly advanced in three respects.

1. Resin formation, expressed in grams of resin formed per 11 catalyst per hour, depends on the carbon content. The following results have been determined by investigations on this dependence of the resin formation on the carbon content of the catalyst solution. A freshly prepared solution of copper chloride and potassium chloride or copper chloride, potassium chloride and ammonium chloride as a catalyst, which shortly after the start of the reaction does not contain any carbon-containing compounds apart from cyanide ions, shows no resin deposition, but only a small amount of resin formation, which initially only increases in the amount of dissolved organic compounds. As the organic complexing agents form in the aqueous layer, the formation of resin begins to increase, and continuously increasing amounts of resin are deposited on the catalyst solution. If the resin formation at a carbon content of 2 ⁰ I _{0 is,} for example, 0.2 g resin per 11 catalyst per hour, it can be below the

same production conditions, for example, up to 1 g resin per 11 catalyst per hour with a carbon content of 10% in the catalyst. The following example shows the great economic importance of this fact. In a device with 100 m ^{3 of} catalyst solution, 14.41 of resin are formed in 1 month (720 hours) with 0.2 g of resin per 11 per hour, and 721 of resin per hour with a resin formation of 1 g per 11 of catalyst solution. Since the resin contains around 40% copper (l) chloride, which is lost, the copper chloride loss alone is 5.761 in the first case, 28.8 t in the second case, i.e. around 23 t more. In reality, the loss is considerably greater, since the yield is reduced in accordance with the content of acetylene and hydrogen cyanide bound in the resin and, as a result of the reduction in the catalyst performance, the overall performance is lower.

2. The removal of the newly formed in the catalyst solution by saponification of hydrocyanic acid and nitriles Ammonium chloride becomes more organic in the presence of non-volatile, soluble Complexing agent sensitively disturbed. This disturbance manifests itself in the following ways: when the catalyst solution is diluted with water, the copper chloride-potassium chloride or Copper chloride-ammonium chloride complex compound, whereby the water-insoluble copper (I) chloride precipitates while the potassium chloride and ammonium chloride remain dissolved and removed will. Were non-volatile in the catalyst solution due to the copper (I) chloride complex Organic complexing agents held in solution are present, these complex compounds also disintegrate when diluted with water, and the organic components precipitate together with the copper chloride and go with Dissolve the copper chloride back into solution with potassium chloride or a catalyst solution. It is coming in this way contributes to a rapid increase in the carbon content and the formation of resin falling catalyst performance and yield. Ultimately is the original aqueous catalyst solution a viscous oily liquid. When this solution is precipitated with water, one obtains a tough plastic mass, which is technically very difficult to process, so that the entire Catalyst solution must be discarded. This is the case with carbon contents of 10 to 16% Case.

3. The catalyst performance increases at a given acetylene partial pressure with increasing molar ratio from CuCl to the sum of all complexing agents. A catalyst solution would have given Acetylene partial pressure the greatest achievable catalyst performance when the molar ratio of CuCl to the sum of CuCl + complexing agent = 1: 1.5. It must therefore be the amount of Complexing agents, including non-volatile, soluble organic complexing agents, if possible can be kept small. However, this proportion was within the sum of all complexing agents so far little or no importance has been attached because this proportion builds up very slowly in the catalyst solution and it was erroneously assumed that it continuously turns into insoluble resin and can thereby be separated. In addition, the known methods are inadequate and associated with disadvantages, so that a safe control of the carbon content of the catalyst solution and the setting of certain Carbon levels was not guaranteed.

ίο To what extent the catalyst performance depends on the content

non-volatile soluble organic complexing agents, expressed by the carbon content the aqueous solution, is illustrated by the following example.

A catalyst with a molar ratio of CuCl to CuCl + KCl + NH ₄ Cl equal to 1: 1.83 and a content of non-volatile, soluble organic complexing agents, corresponding to a carbon content of 7 percent by weight, has a performance at an acetylene partial pressure of 1.8 ata of 35 g of acrylonitrile + monovinylacetylene per 11 and per hour.

If the carbon content is reduced to 3.5 percent by weight by pressure heating according to the invention, the catalyst _{output at the same molar ratio of CuCl to CuCl + KCl + NH 4} Cl is 45 g of acrylonitrile + monovinylacetylene per 11 and per hour, since with a carbon content of 3, 5% the molar ratio of CuCl to the sum of all complexing agents has increased by reducing the organic complexing agents.

The reduction in the formation of the amount of carbon in the catalyst solution is achieved according to the invention achieved as follows.

It is crucial to maintain a minimum amount of potassium chloride in the catalyst solution. A catalyst solution with 40 percent by weight of copper (I) chloride and 0.75 mol of complexing agent per mol Copper (I) chloride contains per 1 kg of catalyst 4.04 mol of copper (I) chloride and 3.03 mol of alkali metal chloride (potassium chloride + Ammonium chloride) as a complexing agent. It has now been found that the carbon content the aqueous catalyst content under otherwise identical production conditions, especially the monovinylacetylene performance and the gas loading depends on the potassium chloride content of the catalyst solution. The investigations showed that the carbon content of the catalyst solution from 6 to 8% approximately increases linearly when the potassium chloride content drops from 12 to 8%. With a further decrease in the level of potassium chloride the carbon content rises more sharply, and there is an almost sudden increase in the Resin formation. These relationships can be seen from Fig. 1, which shows the carbon and Resin curve from an operational test in the form of a diagram, taken merely as an example shows. The lowest permissible value for the amount of potassium chloride is therefore 8% potassium chloride. It recommends accordingly, higher concentrations, e.g. equal molar concentrations, of potassium chloride and ammonium chloride set in the catalyst, that is, according to the above example, 1.51 mol of potassium chloride = 11.2% and 1.51 moles of ammonium chloride = 8.1% by weight.

The method of adding copper (I) chloride is just as important. It is well known that all procedures are based

to remove that formed in the catalyst solution during the reaction of acetylene with hydrocyanic acid Ammonium chloride (or the inorganic complexing agent) on it, the monovalent copper in an insoluble Form transferred, the ammonium chloride and potassium chloride remain in solution and removed.

In all processes for catalyst revitalization, the separated copper chloride was previously used as such, so mostly still moist as a paste, added to the catalyst solution in the device.

It has now been found that when copper (I) chloride is added as a moist paste, a larger amount Resin is formed and the carbon content in the catalyst solution increases rapidly in an ammonium chloride solution faster than in a potassium chloride solution. The effect is the more pronounced, ever higher was the carbon content in the catalyst solution before the addition. The increased resin formation is due to the fact that when adding copper (I) chloride to the catalyst solution in the contraption

after heating it is 1.5 to 3.5%, which corresponds to the formic acid and water-soluble content Saponification products. The method has the advantage that it completely excludes Air and without chemical modification of the effective catalyst can be carried out. It is also completely independent of the solubility behavior of the organic complexing agents. With the through The reactions triggered by the pressure ought to be ίο

1. Polymerization reactions of the still largely uncoordinated organic complexing agents and

2. the conversion of the functional groups that cause complex formation, e.g. saponification

of the nitrile groups, water attachment to the carbon triple bonds act in the aqueous, hydrochloric acid solution.

For example, a copper (I) chloride complexed with 1-cyanobutadiene corresponds to a copper chloride content of 55.6% in a cyanobutadiene polymer, which could be formed as follows:

1. A localized strong increase in monovinylacetylene formation occurs at the point of addition and

2. the copper chloride, which is not yet bound in a complex, prefers the formation of resin.

The method of direct addition of copper chloride therefore only appears to have the advantage that the total added copper chloride to increase the molar ratio of copper chloride to copper chloride + Potassium chloride is used.

In reality, some of the copper chloride is lost through resin formation. With increasing copper chloride addition and thus increasing resin formation is the desired increase in catalyst performance always smaller. This chain reaction does not occur through the removal of the non-volatile, polymeric organic Complexing agents (dissolved resin components) interrupted, it leads to an economically unacceptable Resin formation and thus copper chloride losses, with the aqueous layer of the catalyst solution due to their content of organic complexing agents (carbon content) in the resin layer becomes more similar, until finally no more separation of the two layers can be determined and thus the Implementation is being questioned.

It has now been found, completely surprisingly, that increased resin formation does not occur if one after the invention dissolves the copper chloride in an aqueous alkali metal chloride solution and only then the catalyst solution clogs in the device. There are 0.8 to 0.9, but at least 0.8 moles of potassium chloride per mole Copper (I) chloride required to dissolve it. According to the invention, however, it is possible to use the copper chloride to dissolve in a solution with 0.7 to 0.75 moles of alkali metal chloride, if one considers the density of the catalyst solution adjusts to 1.8 to 1.9 by adding or evaporating water.

The organic complexing agents are removed by heating the catalyst to at least 200 ° C. in a pressure vessel for 0.5 to 2 hours. As a result, the organic compounds in the solution polymerize, deposit as insoluble tar on the catalyst solution and can be skimmed off. Was the carbon content in the catalyst used, 8 to 10 ° / _0, n CH ₂ = CH- CH = CH

I.
CN

CuCl

- / - CH ₂ -CH = CH-CH- \

CN CuCl

In fact, a copper chloride content of the resultant by heat treatment of the catalyst resin was observed by more than 52 ° / _0, when the saponification of the nitrile group has been pushed back by a low content of hydrochloric acid of the catalyst used.

The catalyst obtained after heating always contained more ammonium chloride than the catalyst used. The increase in ammonium chloride is clearly dependent on the acid content of the catalyst used. A preferred embodiment consists in adding 5% of the weight of hydrochloric acid to the catalyst before heating. It is thereby achieved that the precipitating resin remains fluid and can be easily skimmed off, and in that the cupric chloride content of the resin of about 40% copper chloride at 13 to 15 ° / ₀ decreases, that is, there is performed a simultaneous extraction of resin. This extraction is much more effective at temperatures of 200 ° C. and above than an extraction at normal pressure with a large excess of complexing agents, since this method does not fall below a copper chloride content in the resin of 20%. The resin extraction and separation of the soluble resin components can therefore be carried out in one operation.

The method of the invention for the revitalization of the aqueous hydrochloric acid, from copper (I) chloride and Complexing agents, such as potassium chloride and ammonium chloride, existing catalyst solution, which for Production of acrylonitrile from acetylene and hydrocyanic acid was used by removing part of the Catalyst solution from the reaction space, removal of the insoluble resin content, precipitation of the Copper (I) chloride from the remaining catalyst

solution by diluting with water, removing the mother liquor and recycling the precipitated copper (I) chloride into the catalyst stock solution in the reaction chamber, now consists in reducing the formation of the soluble, polymeric organic complexing agents by removing the precipitated copper (I) -chloride dissolves in aqueous potassium chloride solution in which the potassium chloride is present in such an amount that, after the fresh catalyst solution has been returned to the reaction chamber, with an amount of complexing agent of about 20 to 25 percent by weight of KCl + NH ₄ Cl, based on the stock catalyst solution in the reaction chamber, at least 8, preferably 11 to 13 percent by weight of KCl are present in this stock catalyst solution, the portion of the catalyst solution withdrawn from the reaction chamber being optionally ^{heated beforehand to at least about 200 °} C. in a closed room under the saturated steam pressure which is established and for 0.5 to 2 hours only then the insoluble en resin portion removed. In this case, it is expedient to add about 5 percent by weight of about 36% hydrochloric acid to the part of the catalyst solution branched off from the reaction space before heating.

It is advantageous if the precipitated copper (i) chloride with the addition of further copper (I) chloride, Potassium chloride and, if necessary, hydrochloric acid, a fresh catalyst solution that is poor in ammonium chloride in the molar ratio of copper (I) chloride to the sum of potassium chloride and ammonium chloride equals 1: 0.7 to 1: 0.75 and returns it to the reaction space.

The precipitated copper (I) chloride is dissolved in aqueous potassium chloride solution with the addition of insoluble Resin content of purified catalyst stock solution. Loss of copper (I) chloride, hydrogen chloride and water, which is obtained by removing the insoluble resin content and stripping off the mother liquor inevitably arise by adding fresh copper (I) chloride and aqueous hydrochloric acid balanced when the precipitated copper (I) chloride is dissolved. In the catalyst stock solution is im generally maintain at least the same molar concentration of potassium chloride in addition to ammonium chloride.

One possible embodiment of the method of the invention is e.g. B. is that one out of the reaction chamber continuously or periodically one part, generally 15 to 25, preferably about 20 parts by volume Catalyst solution passes into a skimming container, the catalyst solution at the bottom of this skimming container from a reservoir pushes up the insoluble resin floating on the catalyst solution overflows into an extraction vessel and the pressed up portion of the catalyst solution again returned to the storage container, then about a quarter of the resin-removed catalyst solution the skimming container into a measuring container and from this while introducing an inert gas into a A container filled with water for the precipitation of the catalyst passes after the copper (I) chloride precipitate has settled the supernatant aqueous mother liquor is siphoned off and optionally a copper recovery supplies and that the copper (I) chloride precipitate from the precipitation tank as an aqueous Conveys slurry into the dissolving tank and the remaining approximately three quarters of the resin-removed catalyst solution from the skimming container into the dissolving container and there from the precipitated copper (l) chloride with the addition of more copper (I) chloride, potassium chloride and, if necessary, hydrochloric acid, a fresh one Catalyst solution poor in ammonium chloride in the molar ratio of copper (I) chloride to the sum Potassium chloride and ammonium chloride equal to 1: 0.7 to 1: 0.75 are produced and returned to the reaction chamber.

Another embodiment of the method is that one from the reaction chamber continuously or periodically a part, generally 15 to 25, preferably about 20 parts by volume of catalyst solution in a pressure vessel passes and after the addition of hydrochloric acid by briefly heating to about 100 ⁰ C, the dissolved ^{Expels gases and water vapor, then heated to at least about 200 0} C for about 0.5 to 2 hours under the resulting saturated steam pressure, cooled to about 120 ⁰ C, relaxed and the catalyst solution passed into a skimming container, at the bottom of this skimming container the catalyst solution from a Pressing up the storage tank, the insoluble resin floating on the catalyst solution overflows into an extraction tank and the pressed-up portion of the catalyst solution is returned to the storage tank and the resin-removed catalyst solution is transferred from the skimming tank to a measuring tank and from this while an inert gas is introduced into a tank filled with water to precipitate the catalyst, then after the copper (I) chloride precipitate has settled, the supernatant aqueous mother liquor is siphoned off and, if necessary, fed to copper recovery and the copper (I) chloride precipitate from the precipitation tank as an aqueous slurry into the dissolving tank promotes and with the addition of further copper (I) chloride, potassium chloride and optionally hydrochloric acid, a fresh catalyst solution in a molar ratio of copper (I) chloride to potassium chloride equal to 1: 0.7 to 1: 0.75 and this returns to the reaction chamber.

In the dissolving tank, a density is preferably established by adding or evaporating water fresh catalyst solution of 1.8 to 1.9 g per 1 ecm.

From the resin that has accumulated in the extraction vessel, the copper (I) chloride can be extracted as a potassium chloride-copper (I) chloride complex compound with an aqueous potassium chloride solution while stirring at about 120 ^{° C. and under pressure and the extract is transferred to the dissolving vessel or directly into} return the reaction vessel.

The method of the invention is illustrated by the examples and the device (A b b. 2).

Example 1 applies to the constant operating state. According to this procedure, the catalyst solution had the same performance after more than a year.

example 1

From reaction tower 1 with 100 volume units (eg 1001 or 100m ³ ) catalyst solution with a density of 1.65, that is 165 weight units (eg 165 kg or 165 t) and the following composition in percent by weight

40% copper chloride,
12% potassium chloride,
9% ammonium chloride,
7% carbon in the form of dissolved resin components

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become 21.8 volume units per day, corresponding to 35.9 weight units, with a temperature of 85 ° C is drawn off through a lateral connection in the upper third of the liquid level and via the line 2 guided into the skimming container 3. That as a specifically lighter layer on the catalyst solution floating resin is separated by from the catalyst storage container 4 via line 5 the The catalyst solution in stock at the bottom of the creaming vessel 3 is pressed in until the resin layer (1.1 weight units with 40% copper chloride, corresponding to 0.44 weight units of copper (I) chloride) on the upper conical Part of the Abrahmbehälters runs through the channel 6. Now is the one needed for overprinting Amount of catalyst conveyed back into the storage container 4 and that remaining in the skimming container 3 21 volume units are divided as follows: 5.65 volume units are transferred via lines 7 and 8 Out into the measuring container 9, the remainder, ie 15.35 volume units, flow through the line 7 into the Dissolving container 10.

From the measuring vessel 9, 5.65 units of volume of catalyst solution are now allowed to flow through the line 11 into 5.65 units of volume of water, which are located in the precipitation vessel 12, with the introduction of nitrogen as. After the copper (I) chloride precipitate has settled, the supernatant water is siphoned off through line 13 and fed to copper recovery. The siphoned off water contains 0.215 weight units of copper (I) chloride, 0.84 weight units of potassium chloride, 0.63 weight units of ammonium chloride and 0.162 weight units of carbon in the form of organic compounds. The copper (I) chloride precipitate, which consists of 3.515 weight units of copper chloride, 0.28 weight units of potassium chloride, 0.21 weight units of ammonium chloride and 0.49 weight units of carbon as organic compounds, is conveyed through line 14 as an aqueous slurry into dissolving tank 10. Here, the copper (l) chloride lost by the resin deposition in the skimming container 3 and precipitation in the felling container 12 is replaced by the addition of 0.67 weight units of copper (I) chloride. In addition, the amount of 0.840 weight units of potassium chloride required to maintain the potassium chloride level is added. The contents in the dissolving container 10 are brought to a temperature of 95 to 100 ^° C. by heating while stirring. The desired density of the catalyst solution is adjusted to about 1.8 g per 1 ecm by adding water or by evaporation. If necessary, the required amount of hydrochloric acid can (about 0.9 Volumeinheiten 36 / _cent strength hydrochloric acid) is added from the hydrochloric acid storage tank 15 via lines 16 and 17th The finished catalyst solution, which is pushed back from the dissolving tank 10 via the line 18 into the reaction tower 1, contains in weight units

14,485 copper (I) chloride,
4.16 potassium chloride,
2.49 ammonium chloride and
2.28 carbon in the form of dissolved resin components.

The molar ratio of copper (I) chloride to copper (I) chloride + potassium chloride + ammonium chloride is 1: 1.70. The catalyst revitalization is carried out so that a molar ratio in the reaction tower from copper chloride to copper chloride -j- Ka-

60 lium chloride 4-ammonium chloride of 1: 1.83 is maintained. The carbon content of the aqueous catalyst solution is constant at 7%, the catalyst output is 28 g of acrylonitrile per 11 catalyst solution and per hour and 7 g of monovinylacetylene per 11 solution and per hour at a partial acetylene pressure of 1.8 ata.

Example 2

The procedure is as in the first example, with the difference that the potassium chloride is used for preservation of the potassium chloride level must be added to the catalyst solution, only for the extraction of the resin, for example, according to the method of German Patent 1,215,140, is used by the Resin in the extraction tank 19 is heated with an aqueous potassium chloride solution. Will the potassium chloride extract supplied to the dissolving tank 10, so needs according to the copper chloride content of the Extract less fresh copper (I) chloride in the dissolving tank 10 to be added.

The 1.1 weight units of resin, which contain 0.44 weight units of copper (I) chloride and run according to Example 1 from the channel 6 into the extraction container 19, are in this with 0.35 weight units of potassium chloride in the form of a 15 ° / _o aqueous solution extracted under pressure for about 2 hours under stirring and heating to 12O ⁰ C. The extract, which contains 0.33 weight units of copper (I) chloride (^ = 75% of the copper chloride present in the resin), is fed into reaction tower 1 via lines 20 and 18 or into reaction tower 1 via lines 20 and 18 in the opposite direction Dissolving vessel 10 pressed. In this case, only 0.34 weight units of copper chloride and 0.49 weight units of potassium chloride are added to the dissolving vessel and the procedure is as usual.

Example 3

If larger amounts of copper (I) chloride are to be dissolved than in Example 1 and fed to the reaction tower 1, for example in order to increase the catalyst volume, a fresh catalyst is produced in the dissolving tank 10. The solution is brought to 80 according to the invention, 1 mole of copper (I) chloride with 0.75 mol of potassium chloride in solution by 2.7 parts of concentrated in 31.6 parts of water 36 allows ° / _o hydrochloric acid incorporated, ° C and 42 parts of copper (I) chloride and 23.7 parts of potassium chloride are added with stirring. The density of the finished catalyst solution is 1.82 at 8O ⁰ C.

Example 4

As in Example 1, reaction tower 1, which is filled with 100 parts by volume of catalyst solution, without interrupting the reaction and separating off the emulsified, insoluble resin components, 21.8 volume units Catalyst solution is drained into the pressure vessel 21 via lines 2 and 22. The pressure vessel 21 now contains 0.8 volume units of resin with 40% copper chloride and 21 volume units of catalyst solution (= 34.7 weight units) of the following composition in percent by weight:

40% copper chloride,
12% potassium chloride,

9% ammonium chloride and

7% carbon in the form of dissolved resin components.

After 1.7 weight units of concentrated 36% hydrochloric acid have been added via line 16, pressure vessel 21 is indirectly ^{heated to 100 °} C. for about 1 hour, as a result of which the dissolved gases and water vapor escape via exhaust gas line 23. After the exhaust line has been closed, the mixture is ^{heated to 200 °} C., as a result of which the saturated steam pressure at the corresponding temperature is established in the pressure vessel. The temperature of the mixture is kept for 2 hours at about 200 ⁰ C and the mixture, after cooling to 120 ⁰ C discharged through the line 24 into the Abrahmbehälter 3 wherein relaxed via the lines 23 and 25th In the skimming container 3, the upper resin layer is then drawn off, as in Example 1, by pressing in catalyst solution from the catalyst storage container 4 via the channel 6. 2 weight units of resin containing 0.3 weight units of copper chloride are removed. In the skimming container 3, 35 weight units of catalyst solution of the following composition remain in percent by weight:

40 ° / ₀ copper (I) chloride,
12% ammonium chloride,
11.9% potassium chloride and
2.95% carbon in the form of saponification products.

This catalyst solution is conveyed via lines 7 and 8 into the catalyst measuring container 9 and then into the precipitation container. The copper chloride precipitate obtained by precipitating this catalyst is completely free of resinous impurities, since the remaining carbon-containing compounds of 2.95 percent by weight has been converted into really soluble compounds by heating under pressure and is removed during precipitation with the precipitation water. The copper (I) chloride is processed as in Example 1 or 3. It is sufficient if, after certain time intervals, for example after 2 to 6 months, the amount of carbon is adjusted to a maximum of 3.5% by heating the catalyst under pressure and wait until it has risen to 7% again. However, it is more advantageous to continuously free a part of the catalyst from the organic complexing agents and to use this part of the catalyst solution for precipitation. This is advisable because of the high ammonium chloride content of the catalyst heated under pressure, because depending on the addition of hydrochloric acid before use, 25 to 50 g of ammonium chloride are formed per liter of catalyst. If this catalyst is used for precipitation, this newly formed ammonium chloride is removed at the same time. The precipitated copper chloride is pure and free from organic components. The risk of clumping or sticking and the resulting operational disruptions are completely eliminated.

Claims (8)

Patent claims: 1. Process for the revitalization of the aqueous, hydrochloric acid, of copper (I) chloride and complexing agents such as potassium chloride and ammonium chloride, existing catalyst solution, which was used for the production of acrylonitrile from acetylene and hydrocyanic acid, by removing part of the catalyst solution from the reaction chamber, removal of the insoluble resin content, precipitation of the copper (I) chloride from the remaining catalyst solution by dilution with water, removal of the mother liquor and recycling of the precipitated copper (I) chloride into the catalyst stock solution located in the reaction chamber, characterized in that the precipitated copper ( I) chloride dissolves in aqueous potassium chloride solution in which the potassium chloride is present in such an amount that after the fresh catalyst solution has been returned to the reaction chamber with a complexing agent amount of about 20 to 25 percent by weight of KCl + NH ₄ Cl, based on the stock catalyst solution in the Reaction space, at least 8, preferably Only 11 to 13 percent by weight of KCl are present in this stock catalyst solution, the portion of the catalyst solution withdrawn from the reaction chamber being optionally heated beforehand to at least about 200 ° C. in a closed room under the saturated steam pressure for 0.5 to 2 hours and only then the insoluble resin content removed. 2. The method according to claim 1, characterized in that from the precipitated copper (I) chloride with the addition of further copper (I) chloride, potassium chloride and optionally hydrochloric acid a fresh, ammonium chloride-poor catalyst solution in the molar ratio of copper chloride to the sum of potassium chloride and ammonium chloride equals 1: 0.7 to 1: 0.75 and returns to the reaction space. Considered publications: German Patent No. 869,948; German Auslegeschrift No. 1 011 876; U.S. Patent No. 2,632,737; Gmelin's Handbook of Organic Chemistry, System No. 60, part B, 8th edition, 1958, p. 235, last Unit volume. Legacy Patents Considered:
German patents No. 1 211 159.1 212 516.1 215 140. 1 sheet of drawings 709 650,423 9 67 © Bundesdruckerei Berlin