DE2519088C3 - Low pressure process for the production of butynediol and propargyl alcohol - Google Patents

Description

Alkynols are usually prepared by known processes such as those in the United States patents 22 32 867, 23 00 969, 24 87 069, 27 12 560, 27 68 215, 08 140, 32 94 849 and 35 60 576 are described, namely by reacting aldehydes or ketones with an acetylenic hydrocarbon of the general formula R-C = CH, where R is a hydrogen atom or the remainder of a hydrocarbon, z. B. a methyl, vinyl or phenyl radical means. The acetylene or the acetylene hydrocarbon is introduced into the reaction in the form of a gas, while the aldehyde or the ketone is taking the reaction conditions represent liquids or in a liquid solvent or diluent may exist.

As is known, the reaction takes place at moderately elevated temperatures of 50 to 150 ^° C. at atmospheric pressures. Pressures from 2 to 30 atm are usually suggested. Experience has shown, however, that a suitable pressure for compressed gaseous acetylene is less than 10 atmospheres when careful control of the temperature is used. Even at these pressures, however, the acetylene gas was combined with inert gases or vapors, e.g. B. nitrogen, hydrogen or carbon dioxide gas, diluted to reduce the risk of violent decomposition. However, these high pressure reactions still have their limitations due to safety factors.

The ethynylation reactions indicated use any copper (l) acetylide catalyst, which can be generated or activated from copper compounds of various types. These Ethynylation reactions were carried out using the catalyst containing or free of carrier agents Carrier was carried out

These known catalysts often turned out to be easily explosive and difficult to filter

ίο overly active in the undesirable catalysis of the Cupra formation. They are therefore often used together with bismuth compounds in high pressure systems, in order to keep this cupra formation to a minimum. Catalysts containing carrier agents have been disclosed in such high-pressure systems are also used, for example, those with a solution of bismuth and copper nitrates were impregnated, dried and calcined to produce the metal oxide, and that Copper oxide was then converted to an acetylide in situ in the ethynylation reaction. The main disadvantage This reaction is due to the fact that butynediol is not formed quickly enough and the yield is reduced Butindio! per gram of catalyst is comparatively low.

In order to achieve low ethynylation operating costs, it has generally been preferred to use the vehicle-containing one To use catalyst in the form of pellets in a fixed bed plug flow process, diluted Feeding aqueous formaldehyde and injecting acetylene at several points at comparatively apply high pressure so that excess formaldehyde is consumed and to the extent that requires distillation to achieve a product of the necessary purity, kept to a minimum became. However, an undesirable aspect of this embodiment was the high initial cost of the necessary reactors, which had to be designed in such a way that they not only operate the normal Acetylene operating pressures of up to 26 atm, rather

4 (i also withstand the higher pressures, up to 20 times greater than normal pressure and with the acetylene decomposition which occurs occasionally at high pressures with occur.

It has also been suggested that such

■ r, supported catalysts in the form of slurries to be used in reactions taking place with continuous stirring. In such In systems, however, it has so far not only proven necessary to switch the catalyst on at short-term intervals

ίο to remove and clean, but it turned out in addition, despite continuous complete catalyst cleaning and recycling as necessary, at comparatively low formaldehyde conversion rates and relatively high acetylene pressures

• μ work to create at least approximately acceptable space / To achieve time yields. Up to now it has not been possible to add the catalyst containing the carrier at the same time and produce butynediol in an economical low-pressure system (reference is made to 52

mi Chem. Abstract 252, 1693 and 44 Khim. Prom. No. 12, 885-87, 1968). Where such low pressure systems were used, the yield and purity of the Process product is not sufficient for the commercial use of such a system

hi justify. Such procedures have hitherto been required higher operating costs than fixed bed plug flow processes because of the higher cost of product separation and contributed little to cost savings because of

the relatively poor reaction rate and short catalyst life,

As a rule it was found that active acetylide catalysts, those made from copper (I) compounds or from copper (H) compounds in such a way were that a substantial proportion of the copper (II) compound before the formation of the acetylide to copper (I) has been reduced to have a too low carbon / copper ratio, being in this Condition can be described as small, sticky, comparatively explosive particles that are usually substantial Contains amounts of metallic copper. In addition, it was pointed out in the specialist literature that that formed copper (I) acetylide catalysts have an insufficient total surface area and consequently are not very effective in making the alkynol if they are made from cupric compounds under one Acetylene partial pressure of over 2 atm or in the absence of formaldehyde, or in the presence of one of House made from unbalanced amount of acetylene or formaldehyde, or from copper (n) compounds that very soluble or in a medium in which the Copper tends to dissolve, are dispersed, produced are.

In the literature (cf. z. B. USA Patent 35 60 576) it is said that a catalyst based on Copper carbonate or certain other insoluble copper compounds the difficulties identified overcomes. However, it has been shown that a catalyst is very sensitive and permanent Activity loses with a shortage of either formaldehyde or acetylene and, as below stated, can easily detonate when heated to 162 ° C. In complete contrast to this, will the inventive Kaialysator is not permanently damaged by such a shortage and under no circumstances can. Detonated.

The invention relates to a low pressure process for the production of butynediol and propargyl alcohol which formaldehyde with acetylene at a temperature of 60 to 120 ° C in the presence of an ethynylation catalyst is implemented, which may optionally contain bismuth, which is characterized is that the process takes place at a pressure below about 2 at partial acetylene pressure in an aqueous medium Stirring is carried out in the presence of a slurry of the catalyst consisting of a water-insoluble Cuproacetylide powder with about 5-20 wt% copper, 0 to about 3 wt% bismuth on one Magnesium silicate exists as a carrier.

In a preferred embodiment of the process according to the invention, the reaction temperature is about 70 to 120 ° C.

The ethynylation process according to the invention can be carried out batchwise or continuously, with in the latter case preferably the carbonyl compound and acetylene simultaneously and continuously are brought into contact at the specified pressure with the specified catalyst in the form of a & o Slurry in an aqueous medium while performing one with continuous stirring taking place reaction at the specified temperature. Both the generation of the catalyst and the The synthesis of the alkynol can take place continuously and simultaneously. Alternatively, however, first in a separate reaction zone, the catalyst is generated and this is then introduced into the ethynylation reaction zone whereupon the specified reaction can be carried out. As another optional Embodiment of each of the two methods mentioned the catalyst produced (regardless of the type of formation used) can be used for so long until its activity drops below a desired level, at which point the Catalyst can be replaced by fresh catalyst either by complete removal of the the former or by peeling off parts of the same, either continuously or intermittently with simultaneous addition of fresh catalyst that does not regenerate or regenerates separately can be, to the reaction medium while maintaining the level of activity.

The reduction of the copper (II) compound and the subsequent production of the butynediol can be carried out in the same reactor, whereby it can be achieved that both the The catalyst and the alkynol product are generated continuously and simultaneously at all times.

The synthesis is carried out with the catalyst supported on an inert powdery carrier, e.g. B. magnesium silicate, silicon dioxide or carbon-aluminum oxide, preferably magnesium silicate, is applied, at atmospheric pressure with complete safety, since any tendency to explosion of the catalyst is prevented by the inert carrier. The carrier can consist of magnesium silicate with a bulk density of about 0.2 to 1.0 g / cm ³ in powder form, this is mixed with a solution of copper salt (which is optionally mixed with a bismuth compound, which acts as an inhibitor for the polymerization of acetylene acts through copper metal) soaked. The mixture is heated to drive off volatile components and to convert the salts into the copper (II) precursor compound of the active catalyst. The catalyst obtained in this way passes through a sieve with 10 to 300 openings per inch of mesh

Repeated tests have shown that the powdery catalyst according to the invention is based on Copper-impregnated magnesium silicate can neither be detonated nor burned, entirely in contrast to most known such copper-containing catalysts.

Repeated water washes have shown that copper does not wash out of the impregnated carrier is in contrast to carrier materials such as pumice stone and kieselguhr, which are made up after Impregnation all copper can be removed by washing it out with water. It will therefore assumed that a "chemical interaction" between the copper and the molecular lattice of the Magnesium silicate takes place, which is responsible for the fact that the activity of the invention usable catalyst to carry out the process according to the invention in economic reaction rates at low acetylene pressures, with the advantage that neither the Acetylene can decompose spontaneously nor the catalyst can detonate, in complete contrast to the circumstances of the state of the art. It is assumed that this interaction is also responsible for the long service life of the analyzer is responsible.

As a rule, contains that which can be used according to the invention Catalyst about 5 to 20%, preferably about 10 up to 15% copper, based on the total weight of the catalyst. This can also be up to 3%,

preferably 2 to 2.8% bismuth, copper can be determined are by degradation of the catalyst, z. B, with concentrated HCI, and analysis of the solution obtained according to standard methods of quantitative analysis. Usually contains the undeveloped catalyst about 5 to 15% copper, based on the total weight. During use, the percent copper content as the magnesium silicate carrier partially dissolves underneath Release of fresh catalyst surfaces. The catalyst which can be used according to the invention is preferably through Introduction of the acetylene into the formaldehyde / catalyst reaction medium educated

As already mentioned, in the creation of the catalyst, the copper (II) precursor compound is in situ the simultaneous action of the reaction components at the required pressure in one practical aqueous medium at a temperature of about 60 to 120 ° C subjected. At temperatures outside the specified range or in strongly basic or acidic media or at acetylene partial pressures of above 2 atm or in the practical absence of either formaldehyde or acetylene -verden in the Regular catalysts obtained. The catalyst formation temperature is preferably 60 to 120 ° C. The pH of the aqueous medium is in the range from 3 to 10, preferably from 5 to 6. Die The concentration of formaldehyde in the aqueous medium is generally from 5 to 60% by weight, which is more advantageous Way at least 10 and preferably 30 to 40 wt .-%, at the beginning of the reaction.

As a rule, the partial pressure of the acetylene above the aqueous medium is in the range from 0.1 to 1.0. ? .tm, preferably in the range of 0.4 to 1.5 atm.

In carrying out the catalyst formation, nitrogen or another practically inert gas, e.g. B. Methane or carbon dioxide are present, as are the usual components of crude acetylene, e.g. B. Methyl acetylene and ethylene. Oxygen is preferably turned off for safety reasons. With small ones The copper (II) precursor compound provided with a carrier can be used in a cold catalyst approaches neutral formaldehyde solution can be slurried, and the acetylene can be introduced during the Slurry is heated. Similar results are obtained when the catalyst slurry with formaldehyde at a not too high temperature, e.g. B. 70 ° C, heated for several hours before Introduction of acetylene. In the case of larger batches, it can be particularly advantageous to use the copper (II) precursor compound Pour in portions into a hot, neutral formaldehyde solution under acetylene pressure. The aqueous solution can advantageously be a stream which Contains propargyl alcohol and / or butynediol, e.g. B. a recycling stream.

The catalyst formation reaction is preferably continued until the divalent copper is practically completely converted into the copper (I) form, which is when the preferred Copper (II) precursors typically require 4 to 48 hours, after which the entire precursor compound is in contact under the specified conditions was brought. It also proves to be particularly advantageous to use the specified conditions in relation to Temperature, pH and acetylene / formaldehyde concentration equilibrium and range to be maintained throughout the entire analysis process.

Deviations from the specified conditions can occur during the course of the formation reaction however, to be tolerated as the implementation faced minor changes in operating conditions is comparatively insensitive

As the reaction proceeds, the pH of the aqueous medium normally decreases with a Speed, and to an extent that is usually greater, the higher the initial one

ίο acidity of the reaction medium and also the Are reaction temperature. The pH can therefore, and preferably is also, controlled up to one to some extent by starting at the preferred initial pH values of 3 to 10 and up to one to a certain extent by working in the preferred temperature range of 60 to 120 ° C. An additional Control can be done by adding small amounts of acid acceptor, e.g. B. sodium acetate progressive reaction. A further control can take place in that the catalyst formation under continuous stirring is carried out with continuous introduction of fresh neutral Formaldehyde solution in a stirred reaction zone (with an acidic drainage from the copper-containing particles can be filtered off) as the reaction progresses, with all the time dtf acetylene partial pressure is maintained.

As such, the ethynylation reaction involves contacting the reaction components

3d with a partial pressure of no more than about 1.9 atm an aqueous slurry of the specified catalyst in one with continuous stirring reaction takes place at 80 to 120 ° C. The formaldehyde and acetylene are preferably continuously Hch fed into the reaction zone where they enter and preferably below the surface of the aqueous Catalyst slurry are introduced and carefully mixed into this by vigorous stirring, whereupon the drain is continuously withdrawn.

The reaction temperature for the synthesis is expediently 60 to 120 ° C., advantageously 80 to 115 ° C and preferably 85 to 110 ° C. The pH of the reaction mixture is advantageously in the range from 3 to 10, preferably from 4.5 to 7, and can be ion-exchanged or acid acceptor treatment of the continuous feed or maintained by adding a suitable buffering agent.

The formaldehyde concentration in the liquid medium in contact with the suspended catalyst is generally 0.5 to 60%, advantageously at least 0.5, in the course of the ethynylation reaction up to 37%, under steady state conditions. The acetylene partial pressure is usually at least 0.5 atm. The acetylene partial pressure is advantageously im Range from 0.4 to 1.9 atm. The acetylene parial pressure above the aqueous medium is preferably 0.5 to 1.5 atm and the catalyst is in amounts of about 1 to 20 parts by weight per 100 parts by weight of aqueous Medium before. For the purposes of the method according to the invention, in the practical absence of Foreign gases, the partial pressure of acetylene as the total pressure minus the absolute pressure of water and Formaldehyde at the reaction temperature

be bj men.

As with catalyst formation, crude acetylene can be used, but this should be used for safety reasons preferably practically free of oxygen

The effluent from the reaction zone can be heated and / or subjected to reduced pressure to Formaldehyde. Propargyl alcohol and some of the water to volatilize, which condenses and with concentrated refill formaldehyde can be combined for recycling in the ethynylation reactor while suppressing the formation of methanol at appropriate intervals in a continuous operation and supplying the remainder of the effluent as an aqueous alkynol directly to the hydrogenation. Optionally, the Discharge from the reaction zone of a conventional plug-flow ethynylicration are supplied in order to convert any excess formaldehyde that may be present.

All parts and ratios in the examples and claims are based on weight, if nothing else is stated.

Example I.

A. Manufacture of the

according to the invention usable catalyst
as well as two known catalysts

Three catalysts were prepared by mixing 100 g of catalyst support with 100 ml of dei following impregnation solution:

Cu (NOi) '3 H.O 702 g Bi (NO ₁ ), · 5 H ₂ O 120g conc. ENT ₁ 60 g

with water was increased to a total volume of 1200 ml diluted.

The impregnated catalysts were at 120 to Dried at 140 "C and then at 480" C for 6 hours roasted.

catalyst

1 (known)

2 (known)
3

carrier

pumice
Kieselguhr
Magnesium sulfate

yield

123.4
128.1
109.0

Appearance

gray-brown powder
gray-brown powder
gray-green powder

A sample of the impregnated, but undried, catalyst prepared using the indicated carrier was washed extensively with water until no further copper was removed. The known catalysts 1 and 2 lost all of the copper, while the inventive catalyst 3 remained pale blue and (after drying) retained about 75% of the original copper content. To compare the specified catalyst, 10 g of catalyst were ^{treated in each case at 80 c} C and atmospheric pressure, the results listed in the table below being obtained. Here and below, acetylene and formaldehyde are sometimes reproduced by their chemical formula and (K) for Kieselguhr. (MS) written for magnesium silical and (B) for pumice stone.

Days (K)% CH ₂ O C ₂ H ₂ rate (MS)% CH ₂ O C ₂ H ₂ rate. (B)% CH ₂ O C ₂ H ₂ rate. ml ■ min ml · min ml ■ min 1 37 3.3 37 2.1 37 2.4 2 unchanged 6.5 unchanged 2.7 unchanged 4.1 3 unchanged 6.5 unchanged 3.7 unchanged 4.3 4th unchanged 6.4 unchanged 4.5 unchanged 4.3 5 unchanged 6.7 unchanged 5.5 unchanged 4.2 6th 10 9.6 10 7.7 10 6.4 7th 10 9.1 10 7.9 10 6.1 8th 10 90 10 8.1 10 6.0 9 10 8.8 10 8.0 10 5.7 10 OK 8.3 10 8.1 11th 10 8.7 10 8.4 12th 10 9.0 10 9.2 13th 10 8.9 10 9.6 14th 10 8.7 10 9.8 15th 10 9.1 10 9.5 16 10 8.8 10 9.8 17th 10 8.9 10 9.7 18th 10 8.5 10 9.7 19th 20th 9.7 20th 10.2 20th 4th 6.1 4th 7.0 21 4th 6.2 4th 7.1 22nd 10 8.4 10 9.8

Results for (K), (MS) and (B): After filtering. Washing and vacuum drying of the catalyst was the weight recovered Catalysts 9.5 g (K), 93 g (B) and 6.1 g (MS) obtained in the form of reddish-brown powders.

Analysis of the recovered catalysts:

Sample ⁰ A Cn ¹

Cu "" I. tu- '% C

(K)
(MS)

6.4
I2.I

3.8
4.1

2.4
3.2

7.5
12.2

0.8

1.4

The total weight of copper in grams is almost exactly the same in the two samples (K), namely 1.17 g. and (Mi), namely 1.18 g. but the latter had Catalyst lost more support (by leaching) and exhibited a little more carbon and Hydrogen on. Also, the percentage of copper that is remains in the monovalent form, much higher for (MS). The weight loss for (MS) is due on the decrease in magnesium from about 8% to about 0.8% and the decrease in silicon dioxide from about 23% to about 18%. This loss is a process in which the carrier means slowly is dissolved away with simultaneous continuous exposure of additional surface of the active catalyst.

B. Formation of the catalyst and influence
the conditions applied

All test batches were ^{carried out at 80 °} C. and atmospheric pressure. After production under the specified conditions, the catalysts were used for the ethynylation of 10% strength formaldehyde solutions, which were replaced daily. With the exception of test 1, the solutions were not changed during the catalyst formation period.

Vcr- To the quay. Formation rate with 1O ⁰ A

such- used CMiO ml

ansat / e CMiO-Kon / .. "A OMi / g Kai.-min

Rate of improvement compared to
Default. 'Vu

10 * 1
10
19th
38

0.77
0.87
1.04
1.17

24
47
65

*) Fresh 10 ″. Ige maldehyde solution was used for the practice
Stagnant liquid exchanged daily (approx. 7 Sld. workload per day)

C. Catalyst formation

60 g of catalyst powder with a content of 13% copper and 2.5% bismuth on a magnesium silicate carrier (prepared according to the method given in Example 1) were fed in together with 500 ml of an aqueous 10% formaldehyde solution. The mixture was heated to 80 C and acetylene was allowed to ^{enter at 8O 'J} C as needed. After 7 to 8 hours the mixture was cooled and allowed to settle. The liquid was drawn off through a filter and replaced with fresh 10% formaldehyde. After each period of the process, the activity increased as the catalyst continued to form.

Table A.

Days

Daily uptake rate ml C ₂ H ₂ / min.

Analysis at the end of the day *)

% F

% B

4.5
10.7

7.1
6.5

1.8
3.9

Aul'uahnn / rak
ml Cjll · Mm.

16.0
19.2
21.9
24.5
24.6

Aii.iKse on the Knile of the day *)

"■ · I

6.0
4.4
4.4
4.2
4.0

"" IS

4.5 5.4 5.9 6.6 6.9

0.31 0.28 0.35 0.43 0.42

') I = I ormaldelling. Ii = butynediol. P = propargyl alcohol.

Example 2

Half of that produced according to Example I C. Catalyst was placed in the same reactor along with 450 g of a 25% strength formaldehyde solution and ethinylated at 80 ° C. and atmospheric pressure.

Table B.

Style. Rate for

at the interval

Current ml acet./min.

15th
23
30th
37
45
52
59
67

22.0

21.5

18.1

13.7

9.7

6.5

4.2

2.2

1.3

Anal
"AI

19.2
13.5

9.4

5.9

3.8

2.0

1.1

0.60

0.35

"AWAY

8.4 15.3 19.2 25.5 29.0 30.8 31.2 32.2 32.3

0.20 0.21 0.35 0.44 0.42 0.45 0.45 0.48 0.51

*) Abbreviations «see table A.

These experiments were carried out in baffle plates, which were operated at high speeds were moved with turbines. Even under these conditions, a higher shaking speed increases or a better baffle system the reaction rate. The reactor was starting with Acetylene was purged and then acetylene was supplied from a measuring container in a manner that the Atmospheric pressure was maintained.

Example 3

Three experimental batches were carried out in which 10 g of the catalyst described in Example 1 C. with 10%, 19% and 38% formaldehyde, respectively. The catalyst formation liquid was not changed until the catalyst formation was complete. After the catalyst formation has ended the catalysts were evaluated for ethynylation of 10% formaldehyde.

% formaldehyde Required hours Guess with to the Cat production for catalog production 10% shape aldehyde ml OH ^ / min-g KaL 10 60 0.87 19th 48 1.04 38 32 1.17

When repeated experiments were carried out with 10% formaldehyde, the more highly active catalysts lost slowly of activity until after about 1 week they produced the activity of one with 10% formaldehyde Catalyst reached. After reaching this point, the catalyst activity changed very little.

[3 e i s ρ i c I 4

Influence of a shortage of supply
Acetylene or formaldehyde

A catalyst used for an excessively long series of ethynylations of 10% formaldehyde was stirred under nitrogen instead of acetylene at 80 ° C for 6 hours. After flushing the Reactor with acetylene became a normal rate of ethynylic acid: obtain. Analysis of an aliquot of this catalyst indicated that this treatment no monovalent copper was reduced to metallic copper.

Another catalyst that has been used in an inordinately long series of runs with 10% formaldehyde was used, 0.2% formaldehyde was used. After restoring the IO% igcn In the solution, the catalyst showed no damage whatsoever. as can be seen from the following values.

% Formaldehyde
in the trial /

Rate.

ml C2H2 / min-g

Quay.

10
0.2
10
10

0.84
0.10
0.76
0.88

became. Unlike the catalyst of the invention, which is formed slowly and 30 to 60 hours up to Required to achieve maximum activity, this known catalyst was full in a few hours at the most educated. Because of the evolving carbon dioxide, it turned out to be necessary to close the reactor during the Producing this catalyst frequently ventilate and refill with acetylene.

The 10% formaldehyde generation gave a comparatively inert catalyst, and so did the generation with 19% formaldehyde gave a catalyst, the fresh 10% formaldehyde with almost exactly that the same rate of ethinylation as an equal amount of weight of a catalyst which can be used according to the invention, which had been produced with the same concentration of formaldehyde.

Fi e i s ρ i c I 5

Comparative example

Heat stability of the catalyst

according to Example 3 and a catalyst

according to USA patent 35 60 576

A catalyst containing 58 to 60% Kupier (as in U.S. Patent 35 60 576 described) and carefully dried in a vacuum oven at 50 to 55 ° C under high vacuum, after which a small amount of the catalyst was heated in a china spoon. A spectacular lightning development was the result. Appropriate tests using a dozen different samples of catalysts which can be used according to the invention led to no detonation and not even to any visible sign of ignition.

A sample of the catalyst produced according to Example 3 with 12 to 14% copper was in a Oven (under nitrogen atmosphere) heated to 200 ° C. After cooling, the catalyst became Ethynylation used 10% formaldehyde and gave a rate of about 67% of that before High temperature baking had been obtained.

Comparative example

Manufacture and evaluation of a catalyst
according to USA patent 35 60 576

continuous production of ijutindiol

Three approximately 38 liter stainless steel reactors, each agitated by one efficient gas dispersion turbine, were connected in series in such a way that the The reaction mixture in the first reactor overflowed into the second and from there again overflowed into the third. The overflow from the third reactor was centrifuged and the catalyst paste was after Mixing with fresh formaldehyde feed returned to the first reactor. The one from the Liquid separated from the centrifuge was withdrawn through a cleaning filter for process product storage.

To start the system, each reactor was up to its full working volume with 30 1 37% Formaldehyde and 4 kg of a catalyst powder containing 12% copper and 2% bismuth on a magnesium silicate support contained, filled. The system was purged with nitrogen and then with acetylene, whereupon it was heated to 95 ° C. with the addition of acetylene at 0.14 atm. At 95 ° C the acetylene pressure was increased to 0.98 atmospheres and the experiment was then carried out under these conditions drove.

Initially, the rate of acetylene consumption increased in line with the generation of the active Catalyst progress. After about 8 hours this rate reached a steady level and then fell off. Fresh 29% formaldehyde was then added at a rate of 12 liters per hour. introduced as feed, whereby the Process product discharged after the third reactor and the catalyst in the specified manner has been recycled. After 8 hours of operation in the specified manner, the system stabilized, and the contents of the reactors had the following composition.

Basic copper (II) carbonate from the »reagent with reactor no. grade «- degree of purity in powder form of the formula

CuCO ₁ • Cu (OH) ₂ • H ₂ O

formaldehyde

Composition of
Reactor content. %

Butindinl

Propargyl alcohol

was produced and used for ethynylation in the same low-pressure reactors that were used to carry out of the rest of the work program used 3 (process product)

9.3
2.9
0.6

23.9
32.0
34.6

0.7
0.9
1.0

Example 6

A catalyst was prepared by impregnation of 100 g of catalyst with the following solution:

56 g Cu (NO ₁ ). · 3H ₂ O

5 g conc. ENT
65 ecm of water

The impregnated catalyst was dried at I25 ° C and then roasted for 6 hours at 480 ⁰ C. After formation as in Example 3, an aliquot was used in an ethynylation experiment under the same conditions as in Example 2. The experiment was much faster than in Example 2, and it only took 50 hours to reduce the rate to 2.3 ecm of acetylene per minute and to reduce the residual formaldehyde to 0.50%.

Claims (6)

Patent claims: 1. Low-pressure process for the production of butynediol and propargyl alcohol, by reacting formaldehyde with acetylene at a temperature of 60 to about 120 ⁰ C in the presence of an ethynylation catalyst, which can optionally contain bismuth, characterized in that the reaction is carried out at a pressure below about 2 at partial acetylene pressure in an aqueous medium with stirring in the presence of a slurry of a catalyst consisting of a water-insoluble cuproacetylide powder with about 5-20% by weight of copper, 0 to about 3% by weight of bismuth on a magnesium silicate carrier 2. The method according to claim 1, characterized in that the reaction is carried out in the presence a catalyst containing about 2 to 2.8% bismuth 3. Process according to Claims 1 and 2, characterized in that the formaldehyde concentration in the aqueous medium to about 0.5 to 60% by weight. 4. Process according to claims 1 to 3, characterized in that the pH of the aqueous Medium holds at around 3 to 10. 5. Process according to claims 1 to 4, characterized in that the catalyst is in Quantities of about 1 to 20 parts by weight per 100 parts by weight of aqueous medium during the reaction used. 6. Process according to claims 1 to 5, characterized in that one contains a copper oxide A precursor compound containing about 2 to 3% bismuth is used.