CS201012B2 - Method of producing halogenides of alpha-halogenalkylcarbamic acid - Google Patents

Description

(54) A process for producing alpha-haloalkylcarbamic acid halides

The invention relates to a process for the preparation of alpha-haloalkylcarbamic acid halides by reacting N-tert-alkyl-N- (1-alkenyl) carbamic acid halides with hydrogen halide at -78 to +80 ° C.

From Angewandten Chemie, Vol. 74 (1962), pages 848 to 855, it is known to react alkylcarbamic acid chlorides with elemental chlorine to provide the corresponding alpha-chloroalkylcarbamic acid chlorides. However, the products formed are mixtures, both with regard to the degree of halogenation and the position of the incoming halogen atoms. This process is unsatisfactory with regard to the yield and purity of the final substance, as well as to the simplicity and economy of operation.

It has now been found that alpha-haloalkylcarbamic acid halides of the general formula I II.

R —CH, —C NN —C (1) wherein R4 is hydrogen or C až-C alky alkyl and X is halogen are preferably obtained by using N-tert-alkyl-N halides - (1-alkyl) carbamic acids of formula XI co

C = N (II) ^{r 2} R 3 CH = CH

R ⁴ in which r 1, R 2 and R 4 may be the same or different from each other and represent an alkyl group having 1 to 6 carbon atoms, and r 4 and X are as defined above, react with excess hydrogen halide at -78 to + 80 ° C.

The novel alpha-haloalkylcarbamic acid halides of the formula I are prepared according to the invention

Ϊ ^H

R ⁴ —CH, —C — li — C *

X ^x (I) wherein

R ⁴ represents hydrogen or an alkyl radical having I to 20 carbon atoms and X is halogen.

According to the invention, novel halides of alpha-haloethylcarbamic acid, in particular novel alpha-chloroethylcarbamic acid chloride, are produced.

In the case of N-tert-alkyl-N- (1-alkenyl) carbamic acid halides, for example chlorides, fragmentation to tert-alkyl chloride and alpha-chloroethylcarbamic acid chloride occurs quantitatively in accordance with the reaction scheme:

_R @ 1 COCl2 Cl2 + @ + 2HCl

R ^{2 X 3} CH = CH

AND

R ⁴

CH

R ⁴

Η Η η

ZJ-Z i,

In comparison with the known process, the process according to the invention provides, in a simpler and more economical manner, alpha-haloalkylcarbamic acid halides in better yield and higher purity. The processing is considerably simpler since no reaction mixture rich in various components is obtained.

The reaction of tert-alkyl-N- (1-alkenyl) carbamic acid halides, especially hydrogen halides, especially hydrogen chloride, makes it possible to produce, in a particularly pure state and under gentle reaction conditions, a heat-stable halide, especially alpha-chloroalkylcarbaraic acid chloride whereas, when elemental halogen is applied to alkylcarbamic acid chlorides (Ang., cited above), product mixtures are obtained both in the position of the incoming halogen atom and in the degree of halogenation. The tertiary alkyl halide which is formed simultaneously in the reaction is inert under the usual reaction conditions and therefore does not have to be removed as a rule in further reactions of the .alpha.-chloroalkylcarbamic acid chloride.

All of these advantageous results are surprising since the formation of a wide variety of reaction products has to be expected with respect to the highly reactive starting materials.

It should also be emphasized that alpha, beta-unsaturated nitrogen compounds are very easily polymerized or hydrolyzed by the action of acids. Thus, for example, N-vinylpyrrolidone is converted to a mixture of oligomers by the action of minute amounts of inorganic acids (Ullmanns Encyclopedia der tischen Chemie, vol. 14, p. 261). Bull Soc. Chim. Belg., Vol. 65, pp. 291-296 (1956), it is noted that vinyl isocyanate is hydrolysed to acetaldehyde by treatment with an aqueous 12 N solution of hydrochloric acid in acetone.

Hydrogen halide is used, preferably hydrogen bromide and especially hydrogen chloride in excess, preferably in an amount of from 2 to 2.2 moles of hydrogen halide per mole of N-tert-alkyl-N- (1-alkenyl) carbamic acid halide.

As tertiary alkyl radicals R @ ¹ , R @ ² , R @ ² , R @ ² and R @ ² are C? and R 4, which may be the same or different, are those having 4 to 18, in particular 4 to 12, carbon atoms. In particular, tert-butyl and target. amyl radical. Accordingly, the radicals R @ ¹ to R @ 2 may be? denote alkyl radicals having 1 to 6 carbon atoms, in particular methyl or ethyl. R @ 1 is preferably hydrogen or an alkyl radical having 1 to 20, in particular 1 to 12, preferably 1 to 6, carbon atoms; preferably represent hydrogen, methyl or ethyl.

The reaction is carried out at a temperature of from -78 to +80 ° C, preferably from +40 to -78 ° C, preferably from -10 to 20 ° C, at atmospheric pressure or under pressure, preferably at 0.07 to 0.2 MPa. , either continuously or discontinuously. The reaction may be carried out without a solvent, but it is expedient to use solvents which are inert under the reaction conditions. Due to the reactivity of the resulting alpha-haloalkylcarbamic acid halides, the process is preferably carried out under anhydrous conditions. In principle, however, it is also possible to work with an aqueous hydrochloric acid solution. The reaction is preferably carried out in solvents which serve as the reaction medium in the further reaction of the final compound, in particular alpha-chloroethylenecarbamic acid chloride.

Suitable solvents are, for example, aromatic hydrocarbons such as toluene, ethylbenzene, o-, m-, p-xylene, isopropylbenzene, methylnaphthalene, aromatic ethers; halogenated hydrocarbons, in particular chlorinated hydrocarbons, for example tetrachlorethylene, 1,1,2,2- or 1,1,2,2-tetrachloroethane, amyl chloride, cyclohexyl chloride, 1,2-dichloropropane, methylene chloride, dichlorobutane, isopropyl bromide, n-propyl bromide, butyl bromide , chloroform, ethyl iodide, propyl iodide, chlornaphthalene, dichlornaphthalene, carbon tetrachloride, 1,1,1- or 1,1,2-trichloroethane, trichlorethylene, pentachlorethane, 1,2-dichloroethane, 1,1-dichloroethane, n-propyl chloride, 1, 2-cis-dichloroethylene, n-butyl chloride, 2-, 3- and iso-butyl chloride, chlorobenzene, fluorobenzene, bromobenzene, iodobenzene, o-, p- and m-dichlorobenzene, o-, p- or m-dibromobenzene, o- m-, p-chlorotoluene, 1,2,4-trichlorobenzene, 1,10-dibromodecane, 1,4-dibromobutane; ethers such etylenpropyléter, methyl t-butyl ether, n-butyl ethyl ether, di-n-butyl ether, diisobutyl ether, diisoamyléter, diisopropyl ether, anisole, phenetole, cyclohexyl methyl ether, diethyl ether, etylenglykoldimethyléter, tetrahydrofuran, dioxane, thioanisole, beta, beta ^from -dichlordietyléter; ketones, such as methyl ethyl ketone, acetone, diisopropyl ketone, diethyl ketone, methyl isobutyl ketone, mesityl oxide, acetophenone, cyclohexanone, ethylisoamyl ketone, diisobutyl ketone, methylcyclohexanone, dimethylcyclohexanone; esters such as methyl acetate, n-propyl acetate, methyl propionate, butyl acetate, ethyl formate, phthalic acid methyl ester, benzoic acid methyl ester, ethyl acetate, phenylacetate and the higher-boiling esters; aliphatic or cycloaliphatic hydrocarbons such as pentane, heptane, pinane, nonane, gasoline fractions boiling in the range of 70 to 190 ° C, cyclohexane, methylcyclohexane, decalin, petroleum ether, hexane, ligroin, 2,2,4-trimethylpentane, 2,2, 3-trimethylpentane, 2,3,3-trimethylpentane, octane and corresponding mixtures.

The concentration of N-tert-alkyl-N- (1-alkenyl) carbamic acid chloride solutions can vary within wide limits, preferably a concentration range of 1 to 50% by weight is used.

The reaction can be carried out as follows:

The mixture of the starting materials and preferably the solvent is kept at the reaction temperature for 0.1 to 4 hours. Suitably, the N-tert-alkyl-N- (1-alkenyl) carbamic acid halide is present in an inert solvent and hydrogen gas is introduced at a temperature of, for example, from -10 to 0 ° C. After completion of the reaction, the reaction solution is stirred for some time, for example 15 minutes, and the excess hydrogen halide is expelled with nitrogen. Thereafter, the reaction product is separated from the mixture in a conventional manner, for example by crystallization and filtration.

The alpha-haloalkylcarbamic acid halides produced by the process according to the invention, in particular alpha-chloroethylcarbamic acid chloride, are valuable starting materials for the production of lacquer raw materials, textile treatment agents, dyes, pharmaceuticals and plant protection products.

In the following examples, parts are by weight.

Example 1

161.5 parts of N-tert-butyl-N-vinylcarbamic acid chloride are introduced at 0 ° C and 75 parts of hydrogen chloride (gaseous) are added over 60 minutes. The reaction mixture was stirred at this temperature for 15 minutes and the excess hydrogen chloride was purged with nitrogen. The tert-butyl chloride was evaporated under reduced pressure and the .alpha.-chloroethylcarbamic acid chloride was recrystallized in carbon tetrachloride. 136 parts of product are obtained (95% of theory). Melting point 20-21 ° C.

Example 2

175.5 parts of N-t-amyl-N-vinylcarbamic acid chloride are introduced at 10 DEG C. and 75 parts of hydrogen chloride are introduced with stirring. After completion of the reaction, the reaction mixture was further stirred for 30 minutes at room temperature, and the excess hydrogen chloride was purged with nitrogen.

The tert-amyl chloride is evaporated under reduced pressure. 130 parts (91.5% of theory) of .alpha.-chloroethylcarbamic acid chloride with a melting point of 20 DEG C. remained.

Claims (1)

SUBJECT OF THE INVENTION Process for preparing alpha-haloalkylcarbamic acid halides of the formula I Η H _c R ⁴ —CH ₂ —C - li— (I) wherein R ⁴ is a hydrogen atom or a C 1 -C 20 alkyl group and X is a halogen atom, characterized in that the N-tert-alkyl-N- (1-alkenyl) carbamic acid halides of the formula II are .what CH = CH11 (II) i in which R @ ¹ , R @ ² and R @ 3 are the same or different from each other and represent an alkyl group having 1 to 6 carbon atoms and and X are as defined above, reacted with an excess of hydrogen halide at a temperature of -78 to +80 ° C.