DE1906493A1 - Opt subst allyl cyanides from allyl esters - or alcohols - Google Patents

Abstract

Cpds. of formula CR1R2=CR3-CR4R5O-CO-R6 where R1-5 are each H, lower alkyl, or phenyl or cyclohexyl opt. subst. by lower alkyl or -CH2-O-COR6; R6 is H or lower alkyl (pref. C1-4) are reacted with HCN and CuI halide catalyst (pref. an opt. modified Nieuwland catalyst, esp. complexes of CuCl with nitriles e.g. CH2 = CH-CH2CN, C6H5CN, C6H5CH2CN) at 20-200 degrees C, pref. 120-200 degrees C, pref. in gas phase with catalyst on porous support e.g. pumice. Pref. R1-5 = H, or one of R is -CH2O-COR6.

Description

Process for the preparation of 3,4-unsaturated nitriles subject of the invention is a process for the preparation of 3,4-unsaturated nitriles by Reaction of esters of unsaturated alcohols with hydrocyanic acid in the presence of a catalyst based on copper-I-halide.

There are already numerous processes for the production of l-cyano-alkenes known. For example, conversion of a halide, specifically one, provides Chloride of the allyl series, with an alkali cyanide often not the one to be expected Allyl cyanide.

(Bl. [3] 33, 55 (1905), Bl.Soc. Chim.Belg.31, 183 (footnote) (1922), 33, 331 (1924), Ber. 56, 1172 (1923), Liebigs Ann. 596, 96, 133 (1955); DBP 851059).

If a halide (chloride) of the ally series is used with tupier cyanide um, allyl dyanide is obtained as a complex compound with copper (I) chloride. tie Isolation of the nitrile from the complex presents difficulties, in addition, requires that process the use of molar amounts of the expensive copper-I-cyanide (Bl.Soc.Chim. Belg. 31, 176 (1922), U.S. Patent 2,448,755).

The implementation of a halide (chloride) of the ally series is more advantageous with hydrocyanic acid in an aqueous medium in the presence of catalytic amounts of a copper (I) salt a in the pH range 3.0-4.5. The process proceeds without rearrangement of the double bond and allows easy and simple work-up.

For the production of the starting materials, however, is chlorine and for Implementation of caustic soda required. Saline solution falls as a by-product of the reaction at. In addition, certain occur Losses due to saponification of the chloride to the 2; 3-unsaturated alcohol (Liebigs Ann. 631, 21-56 (1960); DSP 872 941, 878,942, Liebigs Ann. 631, 22, 23, 27 (1960)).

Another method makes use of the implementation of an alcohol Allyl series with molar amounts of the expensive copper-I-cyanide using molar Amounts of hydrochloric acid (BI.Soc.chim.

Belg. 39, 466, 468 (1930), B1. Soc. chim.Beig. 42, 427, 429 (1933)).

Furthermore, the production of allyl cyanide by reaction of Allyl formate in turn with molar amounts of copper-I-cyanide using molar amounts Amounts of hydrochloric acid described.

(B1. Soc.chim. Belg. 39, 465, 468 (1930)).

In addition, the production of allyl cyanide by converting a Allyl alcohol with hydrocyanic acid in the presence of copper (I) chloride containing Described catalyst solutions. The technical implementation of this process prepares however, considerable difficulties, since the formation of water changes the composition of the catalyst changed and the isolation of the nitriles continued to be made difficult (Liebigs Ann. 631, 21 (-1960)).

Surprisingly, a particularly simple process for the preparation of 3,4-unsaturated nitriles in addition to carboxylic acids has now been found, which consists in using compounds of the formula in which the radicals A, B, CX and E represent the same or different radicals such as hydrogen or lower alkyl radicals, and one of the radicals mentioned also represents a phenyl or cyclohexyl radical optionally substituted by lower alkyl radicals, R is hydrogen or a lower aliphatic radical , with hydrocyanic acid in the presence of a catalyst based on Eupfer-I halide in the temperature range from about 20 to about 2000 C.

Lower aliphatic radicals (A to E) are preferably those with up to 6 carbon atoms. For the implementation of the method according to the invention The esters used are preferably lower carboxylic acids such as formic acid, Acetic acid, propionic acid or butyric acid use. Of course it is The process according to the invention cannot be carried out on the acids mentioned limited, so that aromatic carboxylic acids may also be used could.

Preferred alcohols are: propene- (1) -ol- (3), 2-methyl-propen- (1) -ol- (3), 2-ethyl-propen- (1) -ol- (3), butene- (2) -ol- (1), butene- (1) -ol- (3), pentene- (2) -ol- (1 ), Pentene- (1) -ol- (3), 3-ethyl-butene- (2r-1- (1), 3-methylbutene- (1) -ol- (3), 2-methylbutene ( 2) -ol- (1), 2-methyl-buten- (l) -ol- (3), hases- (2) -ol- (1), hexen- (l) -ol- (3), l-vinyl-cyclopentanol- (1), Cyclopenten- (1) -ol- (3), 1-vinyl-cyclohexanol- (1), cyclohexen- (1) -ol- (3), 3-hydroxy- (1) -phenyl-propen- (1), 1-hydroxy- (1) -phenyl-propen- (2), butene- (2) -diol- (1,4), butene- (1) -diol- (3,4), 2-methyl-butene (2) -diol- (1,4), 2,3-dimethylbutene- (2) -diol- (1,4), hexen- (2) -diol- (1,4), hexen- (3) -diol- (2,5), hexadiene- (2 , 4) -diol- (1.6), Hexadiene (1,5) diol (3,4).

The esters used are known or can be used according to known methods can be obtained.

In the case of the diesters of isomeric alcohols (e.g. butenediols), if necessary their mixtures are also used.

To carry out the process, the technically occurring one can preferably be used Highly concentrated hydrocyanic acid (up to 10% by weight of water), of course, as well Find anhydrous hydrocyanic acid use. The inventive method is in Temperature range from about 20 to about 200, preferably from about 60 to about 1400 ° C carried out. If you work in the higher temperature range, the implementation is under Pressure carried out, this corresponding to a maximum of the partial pressure of hydrogen cyanide will.

The procedure is explained using the following example: CH2 = CH-CH2-CN C HN ------ 3 CH, = CM-CH, -CPT + CH3-C00 0H2 = cH-CH2-0-CO-CH3 + CH3 (Cu = I-salt) It is essential for carrying out the present process to achieve the highest possible concentration of dissolved Eupfer-I halide in the reaction mixture. This can be done by using solubilizers for the insoluble copper halide (preferably chloride, bromide). Such solubilizers are the alkali and alkaline earth (preferably sodium, potassium, calcium, magnesium, strontium) halides (especially chlorides, bromides) and ammonium chloride, provided water or an amide (preferably formamide, dimethylformamide (US Patent specification 2.227.478)) can be used. Preferred solubilizers for carrying out the process are nitriles, those formed in the reaction being expediently preferred. Although, as stated above, water can also be used for carrying out the process, it is expedient to work in an anhydrous medium, since in this way a possible saponification of the ester used to form alcohol is avoided.

Find in a further preferred embodiment of the method Catalysts use that contain at least molar amounts of copper-I halide in addition contain a halide of an organic amine, as in DRP 588.285 and 583.561 are described.

If necessary, it can be particularly useful as an Eata-.

lysers anhydrous, molten salt mixtures made from Eupfer-I halide and one or more halides of ammonia or non-aromatic, to use organic amine bases, as already described in DRP 697.268. To carry out the process according to the invention, molten salts are used those whose melting point is between about 30 and about 1000.degree. C. are preferred.

Generally speaking, it can be said, last for the implementation of the process according to the invention all known so-called Nieuwland catalyst systems or corresponding modifications based on Eupfer-I chloride are used as described, for example, in the following patents: U.S. Patents No. l, 812,542, 1,811,959, 1,926,039, 1,926,055, 1,926,056, DRP 588,283, 589,561.

The amount of the used catalyst or

The catalyst mixture is dimensioned so that at least 0.1% by weight Eupfer-I halide based on the weight of the ester used stands. In general, it has been found to be advantageous to carry out the reaction with a molar amount of catalyst (based on the content of copper-IZalogenid) to begin, and the catalyst residue remaining after the reaction has taken place for the subsequent ones To use approaches again.

In general, it is advisable to use the ester to implement with about the stoichiometrically required amount of hydrocyanic acid. Possibly However, it may be useful to use an excess of ester (about 2 to 3 times) to work, since the ester then also acts as an extractant for the formed Nitrile and the corresponding carbene acid are used.

The batches are worked up in the customary manner.

The method according to the invention is distinguished from that at the outset mentioned known manufacturing processes for unsaturated nitriles inter alia thereby especially from the fact that it is particularly economical to manufacture and thus inexpensive Starting compounds goes out, since no chlorine is required to produce the same.

In the following examples, the temperature data relate to to ° C.

Example 1 A catalyst solution is prepared as follows: 99 g of copper (I) chloride, 53 g ammonium chloride, 84 ml water, 1.5 ml concentrated hydrochloric acid and approx. 0.5 g copper powder (for the complete reduction of any copper (II) ions present) are under a Heated to 800 in a nitrogen atmosphere. A clear, colorless solution results. to this solution becomes a mixture of 106 g (1 mol) of allyl acetate and 27 g (1 mol) of anhydrous Hydrogen cyanide was added dropwise in the course of 1 1/2 hours and then the reaction mixture reheated for another hour. Then the contents of the flask are placed in a frozen trap distilled in vacuo. The salts remain in the flask.

The contents of the case (151 g) represent, as by titration and gas chromatography was determined to be a mixture which, in addition to water, 47.2 g of allyl cyanide and 42.4 g Contains acetic acid.

The hydrochloric acid residue from the distillation in vacuo is 80 ml of water and 3 ml of concentrated hydrochloric acid are added and the mixture is heated to 800.degree. With this catalyst solution is made with the same amounts of starting product and under Repeat the experiment if the same conditions are met.

Now 222 g of a mixture of 67.2 g are placed in the freezer trap Allyl cyanide and 58.0 g of acetic acid (remainder water) were obtained.

The third repetition results in 245 g of a liquid in the trap, which contain 72.5 g of allyl cyanide and 66.0 g of acetic acid in addition to water.

The yields of the 3 experiments are: allyl cyanide 93% of theory Calculated on employed allyl acetate, boiling point 118.6; Acetic acid 92 ”calculated according to theory on the allyl acetate used, boiling point: 118.5.

Example 2 in 100 g of allyl acetate are 32 g of Eupfer-I chloride and 32 g g trimethylamine hydrochloride suspended and the mixture under Sticksotff to 800 heated. Over the course of 4 hours will be 37 g of hydrocyanic acid were added dropwise. The temperature drops to 700 as a result of the hydrogen cyanide boiling at reflux. 1ch further After 3 hours of refluxing, the contents of the flask are distilled with steam. The oil layer of the distillate floating above is taken up in methylene chloride, separated from the aqueous layer and with deposition of the aze.

drops of water / methylene chloride dehydrated. The solvent will be up distilled off to a transition temperature of 950.

A colorless liquid (67 g) remains in the flask as residue back, the composition of which was determined by gas chromatography: 0.7o allyl alcohol, 29.4k allyl acetate, 68.5 allyl cyanide ,? 1% acetic acid (in this experiment the Acetic acid not fully recorded) This reaches the yield of allyl cyanide 69% calculated on the allyl acetate used and 88% calculated on the converted allyl acetate.

Example 3 The catalyst solution consists of a melt (F:> 300 C) of 20 g of trimethylamine hydrochloride, 20 g of dimethylamine hydrochloride, 20 g Ethanolamine hydrochloride and 50 g Eupfer-I-chloride. At 80 °, in the course of 3 hours a mixture of 200 g (2 mol) of allyl acetate and 27 g (1 mol) of hydrocyanic acid added dropwise and heated after the end of the dropwise addition for 4 hours. After this Upon cooling, the reaction mixture separates into 2 layers. The upper one is decanted and vacuum distilled into a trap. 45 g of a dark one remain as a residue Oels back. The contents of the trap, 161.5 g, were determined by gas chromatography as follows Composition: 1.0% hydrocyanic acid, 0.7% water, 43.8% unchanged allyl acetate, 0.7% Allyl alcohol, 31.2% allyl cyanide, 22.6% acetic acid.

The yield of allyl cyanide is thus 75% and that of acetic acid is 61% of theory, based on the allyl acetate used.

Example 4 To a heated to 80 ° C under a nitrogen atmosphere Suspension of 99 g of copper (I) chloride, 5 g of ammonium chloride in 150 g of dimethylformamide a mixture of 100 gY (1 mol) of allyl acetate and 27 in the course of 2 hours g (1 mol) of hydrocyanic acid were added dropwise and held at this temperature for a further 4 hours. The top clear layer of the reaction mixture is decanted off and in vacuo distilled. The distillate weighs 141 g. 56.5 g of a dark residue remain as a residue Salt back. The lower layer is mixed with 100 g of dimethyl formamide and thus the experiment under the conditions given above with a mixture of 100 g allyl acetate and 27 g hydrogen cyanide repeated.

Then the salt is sucked off the contents of the Eol and the contents of the nutsche washed with 90 g of dimethylfornamide. The mother liquor is distilled in vacuo. Distillate 398 g residue, 68 g salt. The distillates are combined and fractionated. The main run goes at 30-1300 / 750 Torr.

over and weighs 156.4 g.

Composition determined by gas chromatography: 17.6% hydrocyanic acid, 1.1% acetic acid, 15.8% allyl cyanide, 57.3% allyl acetate and 7.4% dimethylformamide.

The residue from this distillation weighs 362 g.

Composition determined by gas chromatography: 12.4% acetic acid, 8.7% allyl cyanide, 2.1 allyl acetate, 76.4% dimethylformamide.

The following yields can be calculated from this: Allyl cyanide 56.2 g = 42% calculated on the ester used or 81% on the ester reacted, acetic acid 46.7 g = 39 or

75%. Allyl acetate recovered 96.6 g ~ 48% of the feed, dimethylformamide recovered .288.6 g = 85% of the stake, Example 5 To 135 g (2 mol) of allyl cyanide are added under nitrogen to 99 g (1 mol) of copper (I) chloride. The complex compound of allyl cyanide with -copper-I-chloride becomes self-heating which is eventually heated to 800.

A mixture of 100 g (1 mol) of allyl acetate and 27 g (1 mol) of hydrocyanic acid is added dropwise to the complex compound in the course of 3 hours and then another 3 Heated to 800 hours. After cooling, the upper clear layer is decanted off and distilled off in vacuo.

The distillate, 149 g, contains 20.5% acetic acid, 77.2% allyl cyanide and 2.0% allyl acetate.

The amount of complex compound remaining in the flask is added to Diluted 135 g (2 mol) of allyl cyanide and repeated the experiment.

After cooling, the reaction mixture is filtered off with suction from salt and the Mother liquor distilled in vacuo.

The distillate, 346 g, contains 1.2% hydrocyanic acid, 17.8% acetic acid, 76.7% Allyl cyanide, 4.2% allyl acetate.

The yield is calculated from this: 141 acetic acid were obtained g = 78.56 based on the ester used; of allyl cyanide 381.0 g; after deduction of 270 g used remain 111.0 g = 83% or on the ester used; Allyl acetate 17.6 g = 8.7% of the amount used are recovered.

Example 6 For a catalyst solution described in Example 1 a mixture of 86 g (1 mol) of allyl formate and 27 g (1 mol) of hydrocyanic acid is added dropwise. The test conditions and the work-up are the same as in Example 1 The experiment, which was repeated twice more, resulted in the following. Results compiled in the table: Try allyl formate allyleyanide Formic acid recovered A 9.0g 10 56.2g 83% 32.9g 71% B 11.3g 15% 48.4g 91% C / 13.7 g 16% 50.5 g 74% 40.5 g 88 Total 34.0 g 155.1 g 115.3 g return - 13% 77% on stake 83% on stake won 87.5% "Sales 96%" Sales Example. 7th To a catalyst solution, the composition of which is described in Example 1, a mixture of 128 g (1 mol) of allyl butyrate and 27 g of hydrocyanic acid in the course of 4 hours to C; '- drips. The duration of the post-reaction is 4 hours. A @ s the conversion mixture the allyl cyanide is distilled with steam. The top floating layer will diluted with methylene chloride, separated from the aqueous layer.

Then the solvent is distilled off and passed through in the residue Gas chromatography shows the content of unchanged allyl butyrate and that of the allyl butyrate formed Allyl cyanide determined.

The residue from the steam distillation is treated with methylene chloride extracted and the amount of butyric acid is determined from the extract by titration.

With the catalyst solution freed from the reaction products the experiment is repeated under the same conditions and with the same quantities.

This double experiment gives: 18.7 g of unchanged ester, 110.8 g allyl cyanide and 152.4 g butyric acid.

The yield of allyl cyanide is 83% calculated on the amount used Amount of ester and 89% of the amount of ester converted.

The yield of 3utyric acid is 86% and 93%, respectively. The usage a copper bromide catalyst leads to the same result.

Example 8 20 g each of the chlorohydrates of trimethylamine and dimethylamine and ethanolamine are melted together with the addition of 50 g of copper-I-chloride.

A mixture of 114 g (1 mol) of methyl allyl acetate and 27 g (1 mol) Hydrocyanic acid is added dropwise to the melt heated to 800 in the course of 2 hours. After heating for a further 3 hours, the contents of the flask are transferred to a thin-film evaporator distilled (temperature of evaporator 100 °, pressure-12 torr.) to be distillate. 125 g received.

The sump weighs 108 g.

The distillate has the following composition: 1.1% hydrocyanic acid, 31.3% Acetic acid, 42.4% methallyl cyanide and 18.1% unchanged methylallyl acetate.

This means that 39.2 g of acetic acid = 65% of the input in this experiment or 81.5% of the conversion and 53.0 g of methallyl cyanide = 65% of the input or 81.5- % of the turnover has been formed.

Example 9 For a catalyst solution consisting of 50 g of copper (I) chloride, 27 g ammonium chloride, 42 ml water, 0.8 ml concentrated hydrochloric acid and a little copper powder, which is heated to 80 ° under nitrogen, becomes in the course of 2 1/2 hours Mixture of 88 g (0.5 mol) of cinnamyl acetate and 14 g (0.5 mol) of hydrocyanic acid were added dropwise. This is followed by a post-reaction of 5 hours more.

After cooling, the oil layer in the reaction flask is repeatedly with Ethyl acetate extracted and the catalyst solution then in vacuo with interposition. evaporated to dryness in a freezer trap.

The salts remaining in the flask are made up by adding 50 ml of water Soldered again - and with this catalyst solution, the experiment as described above repeated.

The contents of the cold traps from both experiments are combined.

The layer of ethyl acetate solution floating above is separated off. In the lower aqueous layer, the content of acetic acid is determined by titration. The poured together ethyl acetate solutions are evaporated. From the The residue is isolated from the cinnamyl cyanide by distillation (boiling point 98-102 ° / 0.1 Torr., B [57-580].

A considerable residue is left on the distillation. at This double test obtained: -44.1 g of acetic acid = 74 of theory and 75.4 g of cinnamyl cyanide = 52.5% of theory based on the ester used.

Example 10 A liquid catalyst which is produced by melting together under nitrogen from 20 g trimethylamine hydrochloride, 20 g dimethylamine hyarochloride, 20 g of ethanolamine hydrochloride and 50 g of copper-I chloride is produced at 800 in the course of 3 1/2 hours a mixture of 88 g (0.5 mol) of 1,4-butene- (2) diol diacetate and 27 g (1.0 mol) of hydrocyanic acid were added dropwise. After a further 2 1/2 hours the contents of the flask become extracted several times at 30-400 with ethyl acetate.

The solvent is then evaporated. The remaining residue is dissolved in hot benzene. The benzene solution is made with the addition of approx. 1 g activated charcoal filtered and finally evaporated. The residue is distilled. After a low flow pass over at 80 - 1000 / 0.07 Torr / 48.3 g of a liquid, which freezes when it cools. The crystals formed are from an oily admixture sucked off and represent almost pure 1,4-Dioyanbuten- (2).

The crystals weigh 34.3 g = 65% of theory based on one set Ester. The oily products (14.0 g) are a mixture of unchanged Starting ester with 1,4-dicyano-butene (2). The resulting acetic acid was in this Do not try in isolation.

Claims (6)

Claims: 1. Process for the preparation of 3,4-unsaturated nitriles in addition to carboxylic acids, characterized in that compounds of the formula in which the radicals AB C, D and E stand for identical or different radicals such as hydrogen or lower alkyl radicals, and one of the radicals mentioned also stands for a phenyl or cyclohexyl radical optionally substituted by lower alkyl radicals, R is hydrogen or a lower aliphatic radical The remainder means that it is reacted with hydrocyanic acid in the presence of a catalyst based on copper (I) halide in the temperature range from about 20 to about 2000.degree. 2. The method according to claim 1, characterized in that - that one uses esters of the formula where R stands for hydrogen or an aliphatic radical having 1-4 carbon atoms. 3. The method according to claim 1, characterized in that the formula is best used, wherein R has the meaning given in claim 2. 4, The method according to claim 1, characterized in that one ester of the formula used in which R has the meaning given in claim 2. 5. The method according to claim 1, characterized in that mixtures the diol esters mentioned in claims 3 and 4 are used 6. Procedure according to claim 1, characterized in that one optionally used as a catalyst modified Nieuwland catalyst used.