CH624925A5 - Process for the preparation of glycinenitriles - Google Patents

Description

The invention relates to a process for the preparation of glycine nitriles by reacting amines with carbonyl compounds and hydrocyanic acid under certain reaction conditions with regard to temperature, reaction time and hydrocyanic acid concentration and optionally treating the nitrile thus formed with acid.

It is known from the German Reichspatent 656 350 that glycolic acid nitrile with an excess of methyl

\

N-H

60

R ^ "

(II)

wherein R1 and R2 have the abovementioned meaning, with formaldehyde and hydrocyanic acid in the presence of water for 0.1 to 4 hours at a temperature of 0 to 80 ° C.

It has now been found that the process of the above patent is a process for the preparation of glycine nitriles of the formula I.

3rd

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R

t

C -R6

R-

CN

(I)

R

6 ^> = 0

(iv),

wherein R3, R4, Rs and R6 may be the same or different and each represent an aromatic, cycloaliphatic or araliphatic radical, R3 and R4 together with the adjacent nitrogen atom also represent members of a heterocyclic radical, R4, R5 and R6 also can each denote a hydrogen atom, R5 and R6 also each denote an aliphatic radical, R3 and R4 can also be further developed if R5 and / or R6 denote an aliphatic, aromatic, cycloaliphatic or araliphatic radical, can represent an aliphatic radical, if amines of the formula III

wherein Rs and R6 have the abovementioned meaning, the concentration of hydrocyanic acid during the reaction being not more than 0.9% by weight, based on the reaction mixture.

It was also found that the process can be carried out advantageously if the glycine nitrile of the formula thus formed

1 -3 t> 5

- H

(III),

wherein R3 and R4 have the abovementioned meaning, with car bonyl compounds of the formula IV

H2C0 +

HCN

(I),

wherein R3, R4, R5 and R6 may be the same or different and each represent an aromatic radical, R5 and R6 20 may also each denote a hydrogen atom, an aliphatic, cycloaliphatic or araliphatic radical, R4 may also represent a hydrogen atom, with an acid is treated at a pH between 1 and 7. The reaction can be represented by the following formulas if Pi-25 peridine and formaldehyde are used:

> Q <-CH2-CN + H20.

The reaction can be represented by the following formulas if acetone and piperidine are used:

0 ÇH ^

H ^ C-C-CH ^ + + HCN> ^ ^ -C-CN + H20.

CH-2

The reaction can be represented by the following formulas if aniline and formaldehyde are used:

HgCO +

Or

+ HCN

->

H-N-CH2-CN

h20,

Compared to the process described in German Offenlegungsschrift 1 543 342, the process according to the invention provides glycine nitriles in a better yield and purity in a simpler and more economical way. The process is particularly suitable for operation on an industrial scale and for continuous operation, offers no essential waste water issues and is practically free of resinous by-products and discolouration, which preferentially form or result at higher reaction temperatures due to the presence of formaldehyde and at higher hydrocyanic acid concentrations the presence of aldehydes or ketones. Complicated cleaning operations and solvent losses are avoided by the aftertreatment; Since large-scale processes using solvent extractions also cause difficulties with regard to trouble-free operation, control and regulation of exhaust gas and waste water, the process according to the invention is more reliable and environmentally friendly.

All of these advantageous properties are surprising in view of the prior art.

Formaldehyde can be used in liquid form or as a gas, generally in the form of its aqueous solution, advantageously from 10 to 50, preferably from 30 to 40, percent by weight solution. Hydrogen cyanide is suitable as a gas or, appropriately, in liquid form or in aqueous solution. The starting amine III can be used alone or in solution, advantageously an aliphatic starting amine III in aqueous solution. The aromatic starting amine III can preferably be used alone or in solution, advantageously in an organic solvent. 40 to 60 percent by weight solutions are advantageous. The three starting 60 substances can be reacted in a stoichiometric amount or each of the components in excess, preferably in an excess over the stoichiometric amount of 0.1 to 5 mol of amine, preferably in the case of aliphatic amines in an amount of 0.1 to 2 moles of amine, in the case of nonaliphatic 65 amines from 0.5 to 1 mole of amine and / or from 0.01 to 0.1 mole of hydrocyanic acid per mole of carbonyl compound IV.

Preferred starting materials III and IV and accordingly preferred end products I are those in their formulas

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R3, R4, R5 and R6 can be the same or different and each represent a phenyl radical or naphthyl radical, a cycloalkyl radical with 5 to 8 carbon atoms or an aralkyl radical with 7 to 12 carbon atoms, R3 and R4 together with the adjacent nitrogen atom also for members of one 5- or O-membered, heterocyclic radical, which can also contain a further nitrogen atom or an oxygen atom, R4, Rs and R6 can also each denote a hydrogen atom, R5 and R6 also each an alkyl radical having 1 to 20, preferably 1 to 8, in particular 1 to 4 carbon atoms or an alkenyl radical having 2 to 20, preferably 2 to 8 carbon atoms, R3 and R4, in each case when Rs and / or R6 denote an aliphatic, aromatic, cycloaliphatic or araliphatic radical, for an alkyl radical with 1 to 20, preferably 1 to 8, in particular 1 to 4 carbon atoms or an alkenyl radical with 2 to 20, preferably 2 to 8 Koh can stand. The aforementioned radicals can also be replaced by groups and / or atoms which are inert under the reaction conditions, e.g. Nitro groups, hydroxyl groups, cyano groups, alkyl groups, alkoxy groups each having 1 to 4 carbon atoms; chlorine atoms, bromine atoms substituting on the phenyl nucleus; be substituted.

For example, Possible starting materials IV: formaldehyde, acetaldehyde, propionaldehyde, n-butyraldehyde, isobutyraldehyde, 2-methylbutyraldehyde, 2-ethylcapronalde-hyd, n-valeraldehyde, isovaleraldehyde, 2,2-dimethylpropionaldehyde, 2,2-dimethyl 3-hydroxypropionaldehyde, n-capron aldehyde, isocapronaldehyde, 2-methylvaleraldehyde, 3-methylvaleraldehyde, 2-ethylbutyraldehyde, 2,2-dimethylbutyraldehyde, 2,3-dimethylbutyraldehyde, 3,3-dimethylbutyraldehyde, oenanthaldehyde, 2- Methylcapronaldehyde, 3-methylcapronaldehyde, 4-methylcapronaldehyde, 5-methylcapronaldehyde, 2-ethylvaleraldehyde, 2,2-dimethylvaleraldehyde, 3-ethylvaleraldehyde, 3,3-dimethylvaleraldehyde, 2,3-dimethylvaleraldehyde, 4-ethylvaleraldehyde, 4,4-dimethylvaleraldehyde, 3,4-dimethylvaleraldehyde, 2,4-dimethylvaleraldehyde, 2-ethyl-2-methyl-butyraldehyde, 2-ethyl-3-methylbutyraldehyde, cyclohexanaldehyde, benzaldehyde, phenylacetaldehyde, Acetone, methyl ethyl ketone, methyl n-propyl ketone, methyl isopropyl ketone, methyl ethyl ketone, methyl n-propyl ketone, Met hyl iso propyl ketone, methyl n-butyl ketone, methyl sec-butyl ketone, methyl tert-butyl ketone, methyl n-pentyl ketone, methyl pentyl (2) ketone, methyl pentyl (3 ) ketone, methyl isoamyl ketone, methyl (2-methyl) butyl ketone, methyl (l-methyl) butyl ketone, methyl (2-ethyl) butyl ketone, methyl (3-ethyl) butyl ketone, methyl (2,2-dimethyl) butyl ketone, methyl (2,3-dimethyl) butyl ketone, methyl (3,3-dimethyl) butyl ketone; Correspondingly asymmetrical ketones which carry the phenyl, benzyl, cyclohexyl, ethyl, n-propyl, isopropyl, n-butyl group instead of the methyl group; Diethyl ketone, di-n-propyl ketone, di-isopropyl ketone, di-n-butyl ketone, di-iso-butyl ketone, di-sec-butyl ketone, di-tert-butyl ketone, di-n-pentyl ketone, di-pentyl (2) -ketone, dipentyl- (3) -ketone, diisoamylketone, di- (2-methyl) -butylketone, di- (l-methyl) -butylketone, di- (2-ethyl) -butylketone, di- (3rd ethyl) butyl ketone, di (2,2-dimethyl) butyl ketone, di (2,3-dimethyl) butyl ketone, di (3,3-dimethyl) butyl ketone, Dicyclohexyl ketone, dibenzyl ketone, benzophenone.

For example, as starting materials III into consideration: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl-a- or - / 3-naphthylamine, where the alkyl substituent is in the 3-, 4-, 5-, 6-, 8- or 2- or 1-position, preferably in the 2-, 4- or 5-position; corresponding to methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl ether of the a- and / 3-naphthylamines carrying a hydroxyl group in the above positions; in the 3,4-, 4,5-, 4,8-, 5,8-, 6,7-position by methyl, ethyl, n-propyl,

Isopropyl, n-butyl, isobutyl, sec.-butyl, tert.-butyl groups disubstituted a- and / 3-naphthylamine; Corresponding dihydroxynaphthalenes, of which 2 hydroxy groups are etherified in the positions indicated by the aforementioned alkyl groups; corresponding a- and / 9-naphthylamines with 2 aforementioned but different residues, e.g. 4-ethyl-8-ethoxy-2-naphthylamine, 4-methyl-5-methoxy-l-naphthylamine; 2-methylaniline, 3-methylaniline, 4-methylaniline, 2-methoxyaniline, 3-methoxyaniline, 4-methoxyaniline, 2,3-dimethylaniline, io 3,4-dimethylaniline, 2,6-dimethylaniline, 3.5 -Dimethylaniline,

2,3-dimethoxyaniline, 3,4-dimethoxyaniline, 3,5-dimethoxyaniline, 2-ethylaniline, 3-ethylaniline, 4-ethylaniline, 2,3-diethylaniline, 3,4-diethylaniline, 2,6-diethylaniline, 3,5-diethylaniline, 2-ethoxy aniline, 3-ethoxy aniline, 4-ethoxy aniline, 2-n-propyl

15 aniline, 3-n-propylaniline, 4-n-propylaniline, 2,3-di-n-propylaniline, 3,4-di-n-propylaniline, 2,6-di-n-propylaniline, 3, 5-Di-n-!

propylaniline, 2-isopropylaniline, 3-isopropylaniline, 4-isopropylaniline, 2-butylaniline, 3-butylaniline, 4-butylaniline, 2-isobutylaniline, 3-isobutylaniline, 4-isobutylaniline, 2-tert.-butylaniline 3-tert-butylaniline, 4-tert-butylaniline, 2,3-diethoxyaniline,

3.4-diethoxyaniline, 2,6-diethoxyaniline, 3,5-diethoxyaniline,

2.3.4-, 3,4,5-, 2,4,6-, 2,3,6-, 2,3,5-trimethylaniline, 2,3,4-,

3.4.5-, 2,4,6-, 2,3,6-, 2,3,5-trimethoxyaniline, 2,3,4-, 3,4,5-,

2.4.6-, 2,3,6-, 2,3,5-triethylaniline, 2,3,4-, 3,4,5-, 2,4,6-,

25 2,3,6-, 2,3,5-triethoxyaniline; in the aforementioned positions, one or more times by hydroxyl groups, nitro groups,

Chlorine atoms and / or bromine atoms instead of the aforementioned alkyl substituents or anilines substituted together with the aforementioned alkyl substituents with the aforementioned phenyl radicals and / or naphthyl radicals disubstituted N-arylamines; preferably diphenylamine, a-naphthylamine, / 3-naphthylamine, in the 2- or 1-position or 4-position by the methyl,

Ethyl, n-propyl group substituted a- or / 3-naphthylamine, 2-methylaniline, 3-methylaniline, 4-methylaniline, 2,3-di-? 35 methylaniline, 3,4-dimethylaniline and especially aniline. 'Methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, pentyl (2), pentyl (3) -, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-tridecyl, n-octadecjd, oleyl, 2-ethylhexyl, 2-ethylpentyl, 3-ethyl- «pentyl-, 4-methylheptylamine; Di- (methyl) -, di- (ethyl) -, di- (n-propyl) -, di- (isopropyl) -, di- (n-butyl) -, di- (isobutyl) -, di- (sec .-butyl) -, di- (tert-butyl) -, di- (pentyl) -, di- (pentyl) - (2) -, di- (pentyl) - (3) -, di- (n- hexyl) -, di- (n-heptyl) -, di- (n-oc-tyl) -, di- (n-nonyl) -, di- (n-decyl) -, di- (2-ethylhexyl) - , Di-45 (4-methylheptyl) amine; corresponding amines with 2 aforementioned but different radicals, e.g. Methylethyl-min; Cyclohexylamine, cyclopentylamine, cycloheptylamine,

Benzylamine, phenylethylamine; Dicyclohexylamine, dicyclopentylamine, dicycloheptylamine, dibenzylamine, diphenylethyla-50 min; Pyrrolidine, A 2-pyrroline, A 3-pyrroline, pyrrole, pyrazole, pyrazoline, pyrazolidine, imidazolidine, hexamethyleneimine, 3-imi-dazoline, piperidine, morpholine, piperazine, indoline, indole, iso-doline, isoindole, indazole, Benzimidazole, 1,2,3,4-tetrahydroisoquinoline, carbazole, phenoxazine, 4-methylimidazole, 2-methyl-55 indole, 3-methylindole, 2-methylpiperazine, 3-methylpyrrole, 2-methylpyrrole, 2-ethylmorpholine , 2-ethylpiperidine, 2-methylpyrrolidine.

The reaction is carried out at a temperature of 0 to 80 ° C in the case of the reaction of aromatic amines between 0 and 80 ° C, advantageously between 40 and 80 ° C, preferably from 45 to 75 ° C, in particular from 50 to 70 ° C, in the case of the reaction of non-aromatic amines, expediently carried out from 10 to 80 ° C., preferably from 10 to 65 ° C., in particular from 15 to 40 ° C., with negative pressure or positive pressure 65 or preferably without pressure, discontinuously or preferably continuously. Water is used, suitably in the form of an aqueous formaldehyde solution and / or amine solutions, and the reaction also forms

5

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even water; a total of 1 to 6, preferably 3 to 4, moles of water, based on carbonyl compound IV, are suitable. Hydrogen cyanide is added to the starting mixture before and during the reaction in such an amount that the concentration during the reaction is expediently not more than 0.9, generally from 0.01 to 0.9, advantageously from 0.01 to 0.8 from 0.01 to 0.7, preferably from 0.01 to 0.1, in particular from 0.05 to 0.1 percent by weight of hydrocyanic acid, based on the reaction mixture. The reaction time (in continuous operation residence time) is 0.1 to 4, preferably 1 to 2 hours. Water is preferably used alone as the solvent, optionally also organic solvents which are inert under the reaction conditions. Examples of solvents are in question: aromatic hydrocarbons, e.g. Toluene, benzene, ethylbenzene, o-, m-, p-xylene, isopropylbenzene, methylnaphthalene; aliphatic or cycloaliphatic hydrocarbons, e.g. Heptane, a-pinene, pinane, nonane, gasoline fractions within a boiling point interval of 70 to 190 ° C, cyclohexane, methylcyclohexane, petroleum ether, decalin, hexane, ligroin, 2,2,4-trimethylpentane, 2,2,3-trimethylpentane , 2,3,3-trimethylpentane, octane; and corresponding mixtures. The solvent is expediently used in an amount of 40 to 10,000 percent by weight, preferably 50 to 500 percent by weight, based on starting material III.

Organic solvents which are inert under the reaction conditions are not necessary, especially in the case of aromatic amines.

The reaction can be carried out as follows: A mixture of carbonyl compound IV, water, hydrocyanic acid and starting amine III, optionally together with an organic solvent, is kept at the reaction temperature during the reaction time. Portions of the hydrocyanic acid are added to the starting mixture and in portions or continuously during the reaction in such a way that the aforementioned hydrocyanic acid concentration is maintained throughout the reaction time. The ongoing measurement of the hydrocyanic acid concentration is expediently carried out using a silver calomelectrode. Then the end product is converted from the reaction mixture in the usual manner, e.g. by separation of the organic phase and distillation or filtration or extraction with e.g. Cyclohexane or ethyl acetate and distillation of the solvent, isolated.

In a preferred embodiment of the working up in the case of N-arylglycine nitriles, the treatment of the reaction mixture after the reaction in the presence of acid is advantageously carried out in an amount of from 0.01 to 2, in particular from 0.1 to 0.5, equivalent to acid 1 mol of starting material III, carried out. Inorganic or organic acids can be used. Instead of monobasic acids, equivalent amounts of polybasic acids can also be used. For example, the following acids are suitable: hydrogen chloride, hydrogen bromide, hydrogen iodide, perchloric acid, sulfuric acid, phosphoric acid, nitric acid, carbonic acid; Sulfonic acids such as benzene and p-toluenesulfonic acid; Acids containing boron, such as boric acid, hydrofluoric acid; aliphatic carboxylic acids such as chloroacetic acid, dichloroacetic acid, trichloroacetic acid, acrylic acid, oxalic acid, formic acid, cyanoacetic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, tetracosanoic acid, he-xacosanoic acid, linoleic acid, linolenic acid, ricinoleic acid, oleic acid, arucic acid, arucic acid, arucic acid, arucic acid, arucic acid, arucic acid, arucic acid, aric acid, arucic acid, , Caproic acid, enanthic acid, pelargonic acid, Ca-prinic acid, 3,5,5-trimethylhexanoic acid, 2-ethylpentene- (2) -acid- re (l), undecylic acid, lauric acid, palmitic acid, stearic acid, 2-ethylhexane carboxylic acid, a-ethylbutyric acid , Methacrylic acid, crotonic acid, isocrotonic acid, tiglinic acid, sorbic acid, undecylenic acid, 2-methylbutanoic acid, glycolic acid, lactic acid, pyruvic acid, acetoacetic acid, levulinic acid, monobromacetic acid, tartaric acid, citric acid, / 3-oxybutyric acid trimethyl / capric acid -Chloropropionic acid, succinic acid, malonic acid, isovaleric acid, valeric acid, glutaric acid, adipic acid, maleic acid; cycloaliphatic, araliphatic, aromatic carboxylic acids such as benzoic acid, 2,3-, 2,4-, 2,5-, 2,6-dimethylbenzoic acid, o-, m- or p-aminobenzoic acid, o-, m- or p- Oxybenzoic acid, meilithic acid, phenylpropionic acid, o-, m- or p-chlorobenzoic acid, cyclohexane carboxylic acid, cyclopentane carboxylic acid, phenyl acetic acid, a- or / 3-naphthoic acid, 2,3-oxynaphthoic acid, cinnamic acid, naphthalene-l, 8-dicarboxylic acid, Phthalic acid, o-, m- or. p-toluic acid, o-, m- or p-nitrobenzoic acid, isophthalic acid, terephthalic acid; Ethylenediaminetetraacetic acid, nitrilo-triacetic acid, diethylenetriaminepentaacetic acid, dyglycolic acid, thiodiglycolic acid, sulfonic diacetic acid; acidic ion exchangers; or corresponding mixtures. The acids can be used in concentrated form, in a mixture with one another and / or with a solvent, in particular water. For aqueous acids, 0.1 to 50 percent by weight acids, e.g. 1 to 10 percent by weight hydrochloric acid, 1 to 25 percent by weight sulfuric acid or 1 to 10 percent by weight phosphoric acid are advantageous. Hydrochloric acid, sulfuric acid, phosphoric acid, p-toluenesulfonic acid, oxalic acid, formic acid, acetic acid, monochloroacetic acid, di- and trichloroacetic acid are preferred. The pH of the treatment is between 1 and 7, preferably from 2 to 5, in particular from 2 to 3.

In the case of N-arylglycine nitriles, the end product can be obtained from the reaction mixture in a conventional manner, e.g. by distillation, isolate and then treat it together with acid and appropriately water at the aforementioned pH, advantageously at a temperature of 0 to 90, preferably from 15 to 70 ° C., without pressure or under pressure, continuously or batchwise, for 5 to 30 minutes under good mixing. In such cases, amounts of from 0.01 to 0.5, advantageously from 0.1 to 0.5 equivalents of acid and from 0.1 to 5, advantageously from 1 to 3, moles of water, based on one mole of starting material III, are preferred; a ratio of 0.05 to 0.2 equivalents of acid per mole of water is advantageous. During the treatment, the aniline in particular surprisingly goes into solution, while the secondary or tertiary N-arylglycine nitrile on the nitrogen atom does not dissolve to any significant extent.

In a preferred embodiment, the treatment with the reaction mixture is carried out after one or more work-up operations, e.g. Redirection in processing plants (stirred tanks, reactors) or advantageously carried out directly after the reaction. The partially or not worked up reaction mixture is expediently mixed with the aforementioned amounts of acid and optionally with 5 to 58 percent by weight of water, based on the reaction mixture, the pH and the temperature are adjusted to the aforementioned treatment temperatures and treatment pH, and the mixture expediently for 5 to 30 Minutes, without pressure or under pressure, continuously or discontinuously at the aforementioned treatment temperatures and pH. Now the end product is processed in the usual way, e.g. isolated from the mixture by distillation, filtration or phase separation.

The glycinnitriles obtainable by the process of the invention are anti-aging agents and valuable starting materials for the production of dyes, fungicides, bacte ricides, textile auxiliaries and inhibitors of anti-freeze agents. By saponification, e.g. by alkali lye, alkali salts of the corresponding glycine are obtained which, especially in the case of a-unsubstituted glycine nitriles, are selective absorbents for CO 2, SO 2 and H2S.

By hydrogenating the glycine nitriles, asymmetric

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60

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6

see diamines, which are valuable starting materials for pharmaceutical and crop protection agents.

Alkali salts of phenylglycine are the starting materials for indigo synthesis. With regard to the use, reference is made to the aforementioned German published patent application and Ullmann's Encyclopedia of Industrial Chemistry, volume 9, page 388, volume 15, page 219, volume 19, pages 300, 317, 339.

The parts listed in the following examples are parts by weight.

example 1

400 parts of a 30% by weight aqueous formaldehyde solution, 108 parts of hydrocyanic acid and 340 parts of piperidine are slowly added hourly in a stirred kettle at 20 ° C., during the reaction the hydrocyanic acid does not exceed 0.1 percent by weight, based on the mixture as a whole. The hydrocyanic acid concentration is on average 0.08 to 0.09 percent by weight, based on the total mixture. The overall response time is one hour. 848 parts of reaction mixture are obtained per hour, which separates into 2 phases. After the organic phase has been separated off, 485 parts of piperidinylglycine nitrile (98% of theory) of Kp18 at 98 ° C. and nD20 = 1.4592 are obtained.

Example 2

400 parts of a 30% by weight aqueous formaldehyde solution, 108 parts of hydrocyanic acid and 396 parts of cyclohexylamine are slowly added in a stirred vessel at 25 ° C., during the reaction the hydrocyanic acid does not exceed 0.1% by weight, based on the mixture as a whole. The hydrocyanic acid concentration averages 0.08 percent by weight. The total response time is 1 hour. 532 parts of cy-clohexylglycine nitrile (96% of theory) of nDz0 = 1.4670 are obtained per hour analogously to Example 1.

Example 3

In a stirred kettle, as described in Example 1, 1566 parts of morpholine, 1800 parts of a 30 percent by weight aqueous formaldehyde solution and 486 parts of liquid hydrocyanic acid are added at 18 ° C., the hydrocyanic acid concentration not exceeding 0.1 percent by weight, based on the total mixture. The hydrocyanic acid concentration averages 0.08 percent by weight. The mixture is left to react for a further hour at 30 ° C. in a downstream reaction vessel. The total response time is 2 hours. After cooling to 0 ° C., N-morpholinylglycine nitrile precipitates, which is suctioned off. 1810 parts of N-morpholinylglycine nitrile (80% of theory) of mp 55 to 57 ° C. are obtained per hour.

Example 4

In a stirred kettle, as described in Example 1, 1278 parts of pyrrolidine, 1800 parts of a 30% by weight aqueous formaldehyde solution and 486 parts of liquid hydrocyanic acid are added at 20 ° C., the hydrocyanic acid concentration not exceeding 0.1% by weight, based on the total mixture. The hydrocyanic acid concentration averages 0.08 percent by weight. The mixture is left to react at 45 ° C for one hour. The total response time is 2 hours. The reaction mixture is heated to 60 ° C., 350 parts of soda being added at the same time. After separation of the organic phase, 1910 parts of N-pyrrolidinoglycine nitrile (95% of theory) of Kp60 are obtained at 111 ° C. and nD20 = 1.4557 per hour.

Example 5

In a stirred kettle, as described in Example 1, 214 parts of benzylamine, 200 parts of a 30% by weight aqueous formaldehyde solution and 54 parts of liquid hydrocyanic acid are added at 20 ° C., the concentration of hydrocyanic acid not exceeding 0.1% by weight, based on the mixture as a whole. The hydrocyanic acid concentration averages 0.08 percent by weight. The reaction mixture is then left to react at 45 ° C. for one hour. The total response time is 2 hours. The organic lower phase is separated off and 281 parts (96% of theory) of benzylglycine nitrile are obtained as a colorless liquid from Kpo.4 111 to 114 ° C. and nD20 = 1.5362 per hour.

Example 6

1530 parts of piperidine, 1044 parts of acetone, 300 parts of water and 486 parts of liquid hydrocyanic acid are slowly added hourly in a stirred kettle at 30 ° C., during the reaction the hydrocyanic acid does not exceed 0.1 percent by weight, based on the mixture as a whole. The hydrocyanic acid concentration averages 0.085 percent by weight. The mixture is left to react at 65 ° C. for 3 hours in a subsequent kettle. The total response time is 3.8 hours. Now the mixture is cooled, extracted with 1000 parts of ethyl acetate and the ethyl acetate is distilled off. 2710 parts (99% of theory) of piperidino-a- (dimethyl) glycine nitrile of mp 37 ° to 38 ° C. are obtained per hour.

Example 7

1530 parts of piperidine, 1908 parts of benzaldehyde, 100 parts of water and 486 parts of hydrocyanic acid are slowly added hourly in a stirred kettle at 65 ° C., during the reaction the hydrocyanic acid concentration does not exceed 0.1 percent by weight, based on the mixture as a whole. The hydrocyanic acid concentration averages 0.085 percent by weight. 3590 parts (99% of theory) of piperidino-a- (phenyl) glycine nitrile of mp 54 ° to 57 ° C. are obtained per hour analogously to Example 6.

Example 8

In a stirred tank, as described in Example 6, 1530 parts of piperidine, 500 parts of water, 1296 parts of n-butyraldehyde and 486 parts of liquid hydrocyanic acid are slowly added hourly at 27 ° C., during the reaction the hydrocyanic acid concentration being 0.1 percent by weight, based on the total mixture, does not exceed. The hydrocyanic acid concentration averages 0.085 percent by weight. The mixture is left to react in a subsequent kettle at 30 ° C. for 2 hours. The total response time is 3 hours. The upper organic phase formed is separated off and distilled. 2980 parts (99% of theory) of piperidino-a- (propyl) glycine nitrile with a bp of 0.02 mbar at 52 ° C. and nD20 = 1.4617 are obtained per hour.

Example 9

In a stirred tank, as described in Example 6, 370 parts of n-dodecylamine, 212 parts of benzaldehyde, 50 parts of water and 54 parts of hydrocyanic acid are added slowly at 45 ° C., the hydrocyanic acid concentration being 0.1 percent by weight, based on the Total mixture, does not exceed. The hydrocyanic acid concentration averages 0.085 percent by weight. In a subsequent kettle, the mixture is left to react at 55 ° C. for 2 hours. The total response time is 3V2 hours. The upper organic phase formed is separated off at 55 ° C. and distilled. 586 parts (97% of theory) of a-phenyl-N-n-dodecyl-aminoacetonitrile nD20 = 1.49 28 are obtained per example 6.

Example 10

370 parts of n-dodecylamine, 144 parts of n-butyraldehyde, 50 parts of water and 54 parts of liquid hydrocyanic acid are added in a stirred kettle, as described in Example 6, at 55 ° C., during the reaction the hydrocyanic acid concentration being 0.1% by weight, based on the total mixture, not

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exceeds. The hydrocyanic acid concentration averages 0.085 percent by weight. The mixture is left to react in a subsequent kettle at 50 ° C. for 2 1/2 hours. The total response time is 3 V2 hours. The organic upper phase is separated off. After extraction with 5 300 parts of ethyl acetate analogously to Example 6, 520 parts (97% of theory) of a-n-dodecylamino-a-n-propylacetonitrile, nD20 =

1.4505.

Example 11

400 parts per hour of 30% by weight aqueous formaldehyde solution, 108 parts of liquid hydrocyanic acid and 372 parts of aniline are slowly added in a stirred kettle at 65 ° C., the hydrocyanic acid concentration in the reaction space not exceeding 0.1% by weight (based on the reaction mixture). The average hydrocyanic acid concentration is 0.08 percent by weight. After an average residence time of 60 minutes, the reaction mixture is fed into a reactor whose temperature is 65 ° C. The average residence time in the reactor is 45 minutes. The hydrocyanic acid concentration is on average 0.04 percent by weight. 880 parts per hour of a reaction mixture are obtained, from which 512 parts (98% of theory) of phenylglycine nitrile of nD50 = 1.5591 per hour by extraction with benzene and evaporation of the benzene; Mp = 40 to 42 ° C (from a 1: 1 mixture of cyclohexane-iso-propanol) is obtained. 25th

Example 12

400 parts of 30% by weight aqueous formaldehyde solution, 108 parts of liquid hydrocyanic acid and 372 parts of aniline are slowly added in a stirred kettle at 65 ° C., the hydrocyanic acid concentration in the reaction space being 0.9% by weight (based on the reaction mixture)

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is not exceeded. The average hydrocyanic acid concentration is 0.8 percent by weight. After an average residence time of 60 minutes, the reaction mixture is fed into a reactor whose temperature is 65 ° C. The average residence time in the reactor is 45 minutes. The hydrocyanic acid concentration is on average 0.5 percent by weight. 880 parts per hour of a reaction mixture are obtained, from which 512 parts (98% of theory) of phenylglycine nitrile of nDs0 = 1.5591 per hour by extraction with benzene and evaporation of the benzene; Mp = 40 to 42 ° C (from a 1: 1 mixture of cyclohexane-iso-propanol) is obtained.

Example 13

400 parts of 30 percent by weight aqueous formaldehyde solution, 108 parts of liquid hydrocyanic acid and 372 parts of aniline are slowly added in a stirred kettle at 65 ° C., the hydrocyanic acid concentration in the reaction space being 0.1 percent by weight (based on the reaction mixture)

is not exceeded. The average hydrocyanic acid concentration is 0.08 percent by weight. After an average residence time of 60 minutes, the reaction mixture is passed into a reactor whose temperature is 65 ° C. The average residence time in the reactor is 45 minutes. The hydrocyanic acid concentration averages 0.04 percent by weight. This gives 880 parts of reaction mixture per hour, into which 57 parts of 12.8% by weight hydrochloric acid are added per hour in a second stirred kettle and the mixture is kept at pH 2. The average residence time in the second stirred tank is 25 minutes at 65 ° C. It is now separated in a separator and 523 parts (99% of theory) of phenylglycine nitrile of nD50 = 1.55 91 are obtained per hour; Mp = 42 ° C (from a 1: 1 mixture of cyclohexane-iso-propanol).

Claims (2)

624 925 2nd PATENT CLAIMS 1. Process for the preparation of glycine nitriles of the formula I R- R- i R .N - C - CN R6 (I), wherein R3, R4, Rs and R6 may be the same or different and each represent an aromatic, cycloaliphatic or an aliphatic radical, R3 and R4 together with the adjacent nitrogen atom also represent members of a heterocyclic radical, R4, R5 and R6 in addition can also denote a hydrogen atom in each case, Rs and R6 also each denote an aliphatic radical, R3 and R4 can also each stand for an aliphatic radical if R5 and / or R6 denote an aliphatic, aromatic, cycloaliphatic or araliphatic radical, characterized in that that amines of the formula III R (HI) 3 wherein R3 and R4 have the abovementioned meaning, with car bonyl compounds of the formula IV R R \ 6 / C = 0 (IV), wherein R5 and R6 have the abovementioned meaning, and with hydrocyanic acid in the presence of water for 0.1 to 4 hours at a temperature of 0 to 80 ° C, the concentration of hydrocyanic acid during the reaction not more than 0.9 wt. -%, based on the reaction mixture. 2. The method according to claim 1, characterized in that the glycine nitrile of formula I thus formed R5 l c - R6 CN can convert amine in aqueous solution under pressure to sarcosinitrile. In order to achieve good yields of sarcosine nitrile, an excess of up to 10 moles of methylamine per mole of oxacetonitrile is recommended (DRP 656 350). When using 5 stoichiometric amounts, the difficult to remove nitrii of methyldiglycol-amic acid is formed. Another way of preparing N-alkyl-substituted glycine nitriles starts from formaldehyde in the presence of sodium trisulfite compounds and converts the aldehyde with sodium cyanide and aliphatic amines. Working with sodium cyanide and sodium bisulfite offers environmental problems for the technical implementation due to the formation of alkali salts, which may contain residual cyanides, as by-products. It is also known to use the amines in the form of salts, e.g. Chlorides, to be used (Jean Mathieu and Jean Weil-Raynal, Formation of C-C-Bonds, Vol. I, pages 442 to 446 (Georg Thieme Verlag Stuttgart 1973). All of these processes are unsatisfactory in terms of simple and economical operation, good yield of end product and easy work-up, especially with regard to environmental protection and wastewater treatment. It is known from German Offenlegungsschrift 1 543 342 to continuously react aniline with formaldehyde and hydrocyanic acid at a temperature between 80 and 130 ° C. and to saponify the reaction mixture with alkali metal hydroxide. The phenylglycine nitrile itself is not isolated. It is stated that the hydrocyanic acid and the formaldehyde are generally present in the reaction mixture in less than 10%, often only 30 1 to 5% in free form. No free hydrocyanic acid is used in all examples. During production, especially on a large industrial scale, the end product is always mixed with a significant proportion of unreacted aniline. The addition occurs again as an impurity in the saponification to the phenylglycine potassium salt. In the later indigo synthesis, aniline must be removed, which is only partially possible by extraction with an inert solvent such as cyclohexane, benzene or toluene. The process is unsatisfactory in terms of simple and economical workup and good yield. CH Patent No. 619 926 relates to a process for the preparation of N-alkylglycine nitriles of the formula Ia R (I), in which R3, R4, R5 and R6 can be the same or different and each represent an aromatic radical, R5 and R6 can also each denote a hydrogen atom, an aliphatic, cycloaliphatic or araliphatic radical, R4 can also represent a hydrogen atom, with a Acid treated at a pH between 1 and 7. R N-CH2-CN (là), so wherein R1 and R2 can be the same or different and each represent an aliphatic radical, R2 can also denote a hydrogen atom, by reacting formaldehyde with amines and cyano compounds by using N-alkylamines of the formula II 55