EP0000362B1 - Alpha-halogeno-alkyl carbamyl halides and preparation thereof. - Google Patents

Description

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

It is known from Angewandte Chemie, Volume 74 (1962), pages 848 to 855, that alkylcarbamic acid chlorides are reacted with elemental chlorine in the corresponding α-chloroalkylcarbamic acid chlorides. The resulting products, however, are mixtures with regard to both the degree of halogenation and the position of the halogen atoms entering. The process is unsatisfactory in terms of yield and purity of the end product and simple and economical operation.

worin R⁴ ein Wasserstoffatom oder einen Alkylrest mit 1 bis 20 Kohlenstoffatom bedeutet und X ein Halogenatom bezeichnet, gefunden.There are now the new a-haloalkylcarbamic acid halides of the formula

wherein R ^{4 represents} a hydrogen atom or an alkyl radical having 1 to 20 carbon atoms and X denotes a halogen atom.

worin R⁴ ein Wasserstoffatom oder einen Alkylrest mit 1 bis 20 Kohlenstoffatomen bedeutet und X ein Halogenatom bezeichnet, vorteilhaft erhält, wenn man Vinylisocyanat oder N-tert.Alkyl-N-(1-alkenyl)-carbamidsäurehalogenide der Formel

worin R⁴ ein Wasserstoffatom oder einen Alkylrest mit 1 bis 20 Kohlenstoffatomen bedeutet und X ein Halogenatom bezeichnet, die Reste R', R² und R³ gleich oder verschieden sein können und jeweils Alkylreste bedeuten, mit Halogenwasserstoff bei einer Temperatur von -78°C bis +80°C umsetzt.It has also been found that a-haloalkylcarbamic acid halides of the formula

wherein R ^{4 represents} a hydrogen atom or an alkyl radical having 1 to 20 carbon atoms and X denotes a halogen atom, is advantageously obtained if vinyl isocyanate or N-tert.alkyl-N- (1-alkenyl) carbamic acid halides of the formula

wherein R ^{4 represents} a hydrogen atom or an alkyl radical having 1 to 20 carbon atoms and X denotes a halogen atom, the radicals R ', R ² and R ^{3 may be the} same or different and each represent alkyl radicals, with hydrogen halide at a temperature of -78 ° C. up to + 80 ° C.

Furthermore, the new a-haloethylcarbamoyl halides, especially the new a-chloroethylcarbamoyl chloride, were found.

If vinyl isocyanate and hydrogen chloride are used, the reaction can be represented by the following formulas:

In the case of N-tert.alkyl-N- (1-alkenyl) carbamic acid halides, for example the chlorides, fragmentation occurs quantitatively in accordance with the reaction equation. Alkyl chloride and a-chloroethyl carbamide chloride.

In view of the known process, the process according to the invention provides α-haloalkylcarbamic acid halides in a better yield and purity in a simpler and more economical way. Working up is much easier since no component-rich reaction mixture is obtained.

The reaction of tert-alkyl-N- (1-alkenyl) carbamic acid halides, in particular the chlorides, with hydrogen halide, in particular hydrogen chloride, allows the thermostable halide, in particular a-chloroalkylcarbamic acid chloride, to be prepared in a particularly pure form and under gentle reaction conditions , whereas with the action of elemental halogen on alkyl carbamic acid chlorides (Ang., loc. cit.) product mixtures are obtained with regard to the position of the halogen atom entering and the degree of halogenation. The tertiary alkyl halide which is obtained at the same time in the reaction is inert under the usual reaction conditions and therefore generally does not have to be removed in the further reactions of the a-chloroalkylcarbamic acid chloride.

All of these advantageous results are surprising, because in view of the very reactive starting materials, the formation of various reaction products was to be expected. It was also assumed that α, β-unsaturated nitrogen compounds polymerize or hydrolyze very easily under the action of acids. For example, N-vinylpyrrolidone by the action of even small amounts of inorganic acids in a mixture of oligomers via (Ullmanns Encyclopedia of Industrial Chemistry, Volume 14, page 261). Bull. Soc. Chim. Belg., Vol. 65, pages 291 to 296 (1956) shows that vinyl isocyanate hydrolyzes with aqueous 12 N hydrochloric acid in acetone to acetaldehyde.

Vinyl isocyanate can e.g. by reacting acrylic acid chloride with sodium azide (Bull., loc. cit.) or by thermal decomposition of N-tert-butyl-N-vinylcarbamic acid chloride. The hydrogen halide, advantageously hydrogen bromide and in particular hydrogen chloride, is used in a stoichiometric amount or in excess, preferably in an amount of from 2 to 2.2 mol of hydrogen halide per mol of vinyl isocyanate or N-tert.alkyl-N- (1-alkenyl) carbamic acid halide .

Suitable tertiary alkyl radicals, R ¹ , R ² and R ³ , which may be the same or different, are those having 4 to 20, in particular 4 to 12, carbon atoms. The tert-butyl and tert.A-myl radicals should be mentioned in particular. Accordingly, the radicals R 'to R ³ in the formula given can be alkyl radicals having 1 to 6 carbon atoms, in particular methyl and ethyl. R ⁴ advantageously denotes hydrogen or an alkyl radical having 1 to 20, in particular 1 to 12, preferably 1 to 6, carbon atoms; hydrogen, methyl and ethyl are preferred.

The reaction is carried out at a temperature of from -78 ° C. to + 80 ° C., advantageously from + 40 ° C. to -78 ° C., preferably in the case of vinyl isocyanate from + 30 ° C. to -78 ° C., in particular at 0 ° C. to -40 ° C, preferably in the case of N7tert.Alkyl-N- (1-alkenyl) carbamic acid halides from -10 ° C to 20 ° C, without pressure or under pressure, preferably at 0.7 to 2 bar, continuously or batchwise carried out. You can sit without solvent, but it is expedient to use solvents which are inert under the reaction conditions, and water is not used in the case of vinyl isocyanate. Because of the reactivity of the resulting a-haloalkyl carbamic acid halides, it is preferred to work anhydrous; in principle, you can also work with aqueous hydrochloric acid. It is preferred to work in solvents which are used as the reaction medium in the further reaction of the end product, in particular the a-chloroethylene carbamic acid chloride. Examples of suitable solvents are: aromatic hydrocarbons, for example toluene, ethylbenzene, o-, m-, p-xylene, isopropylbenzene, methylnaphthalene, aromatic ether; Halogenated hydrocarbons, in particular chlorinated hydrocarbon, for example tetrachlorethylene, 1,1,2,2- or 1,1,1; 2-tetrachiorethane, amyl chloride, cyclohexyl chloride, 1,2-dichloropropane, methylene chloride, dichlorobutane, isopropyl bromide, n-propyl bromide, butyl bromide, Chloroform, ethyl iodide, propyl iodide, chloronaphthalene, dichloronaphthalene, carbon tetrachloride, 1,1,1- or 1,1,2-trichloroethane, trichlorethylene, pentachloroethyne, 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-, m-dibromobenzene, o-, m-, p-chlorotoluene, 1,2,4-trichlorobenzene, 1,10-dibromodecane, 1,4-dibromobutane; Ether, "for example ethylene propyl ether, methyl tert-butyl ether, n-butyl ether, di-n-butyl ether, diisobutyl ether, diisoamyl ether, diisopropyl ether, anisole, phenetol, cyclohexylmethyl ether, diethyl ether, ethylene glycol, dimethyl ether, t-ethyl dimethyl ether, t-dimethyl ether, t-ethyl dimethyl ether, t-dimethyl ether, t-dimethyl ether, t-dimethyl ether, t-dimethyl ether, t-dimethyl ether, t-dimethyl ether, t-ethyl dimethyl ether, t-dimethyl ether, t-dimethyl ether, t-ethyl dimethyl ether, t-ethyl dimethyl ether, t-ethyl dimethyl ether, t-dimethyl ether, t-dimethyl ether, t-dimethyl ether, t-dimethyl ether, t-ethyl ether, t-dimethyl ether, t-dimethyl ether, t-dimethyl ether, t-dimethyl ether, t-ether, t-ethyl ether '-Dichlordiäthyläther; ketones such as methyl ethyl ketone, acetone, diisopropyl ketone, diethyl ketone, methyl isobutyl ketone, mesityl oxide, acetophenone, cyclohexanone, Äthylisoamylketon, diisobutyl ketone, methylcyclohexanone, dimethylcyclohexanone; esters such as methyl, n-propyl acetate, methyl propionate, butyl acetate, ethyl formate, phthalic methyl acid ester, methyl benzoate, ethyl acetate, phenyl acetate and higher-boiling esters; aliphatic or cycloaliphatic hydrocarbon, e.g. pentane, heptane, pinane, nonane, gasoline fractions within a boiling point interval 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 solvent is expediently used in an amount of 200 to 10,000 percent by weight, preferably 300 to 2,000 percent by weight, based on the starting material vinyl isocyanate.

The concentration of the solutions of the N-tert.alkyl-N- (1-alkenyl) -carbamic acid chlorides is variable within wide limits. A concentration range between 1 and 50 percent by weight is preferably used.

The reaction can be carried out as follows: A mixture of the starting materials and advantageously solvents is kept at the reaction temperature for 0.1 to 4 hours. Vinyl isocyanate is advantageously placed in the solvent and gassed with the hydrogen halide at the reaction temperature. The reaction solution is expediently stirred for 0.25 hours to one hour. The N-tert.alkyl-N- (1-alkenyl) carbamic acid halide is advantageously placed in an inert solvent and gassed with hydrogen halide at a temperature of, for example, -10 ° C. to 0 ° C. After the reaction has ended, the reaction solution is stirred for some time, for example 15 minutes, and excess hydrogen halide is blown out using N ₂ . Then the end product is separated from the mixture in a conventional manner, for example by crystallization and filtration.

The a-haloalkylcarbamic acid halides produced by the process of the invention, in particular the a-chloroethylcarbamic acid chloride, are valuable starting materials for the production of paint raw materials, textile coating compositions, dyes, pharmaceuticals and crop protection agents.

The parts mentioned in the examples are parts by weight.

example 1

69 parts of vinyl isocyanate are placed in 250 parts of carbon tetrachloride. 73 parts of hydrogen chloride are introduced into this solution at -35 ° C. within one hour. The reaction solution is stirred for a further 15 minutes at this temperature. After filtration, 137 parts (95% of theory) of a-chloroethylcarbamoyl chloride, melting at 21 ° C., and an NMR spectrum in CCI ₄ (standard tetramethylsilane) are obtained.

Example 2

161.5 parts of N-tert.butyl-N-vinylcarbamic acid chloride are introduced at 0 ° C. and 75 parts of hydrogen chloride are gassed in for this purpose within 60 minutes. The reaction mixture is stirred for 15 minutes at this temperature and excess HCl is blown out with N ₂ . Tert.butyl chloride is stripped off under reduced pressure and the α-chloroethylcarbamic acid chloride is recrystallized in CCI ₄ . 136 parts (95% of theory); Mp 20/21 ° C.

Example 3

175.5 parts of N-tert.amyl-N-vinylcarbamic acid chloride are introduced at 10 ° C. and 75 parts of HCl are introduced with stirring.

After the reaction has ended, the reaction mixture is stirred for a further 30 minutes at room temperature and excess HCl is blown out with N ₂ .

The tert. Amyl chloride is removed under reduced pressure.

There remain 130 parts (91.5% of theory) of a-chloroethylcarbamoyl chloride, mp. 20 ° C.

Example 4

50 parts of vinyl isocanate are placed in 150 parts of dichloromethane. 125 parts of hydrogen bromide at -20 ° C. are introduced into this solution within 70 minutes. The reaction solution is stirred for a further 40 minutes at this temperature. After filtration, 150 parts (90% of theory) of a-bromoethylcarbamic acid bromide, melting at 55 ° C., and an NMR spectrum in CDCI ₃ (standard tetramethylsilane) are obtained.

Claims (4)

1. a-Haloalkylcarbamyl halides of the formula

where R⁴ denotes hydrogen or alkyl of 1 to 20 carbon atoms and X denotes halogen.

2. A process for the production of α-haloalkylcarbamyl halides of the formula

where R⁴ denotes hydrogen or alkyl of 1 to 20 carbon atoms and X denotes halogen, characterized in that vinyl isocyanate or a N-tert-alkyl-N-(1-alkenyl)-carbamyl halide of the formula

where R⁴ denotes hydrogen or alkyl of 1 to 20 carbon atoms, X denotes halogen, and the radicals R¹, R² and R³ are identical or different and denote alkyl radicals, is reacted with a hydrogen halide at a temperature of -78°C to +80°C.

3. a-Haloethylcarbamyl halides.

4. a-Chloroethylcarbamyl chloride.