Bayer Aktiengesellschaft

Herbert Schwarz

Kurt Findeisen

Fritz Doring

Erich Klauke

Hermann Hagemann

Wilfried Draber

Rudiger Schubart

Eckart Kranz

Peter Siegle

Gerhard Buttner

Heinrich Steude

Hermann D Krall

Acyl cyanides of the general formula ##STR1## in which R represents alkyl or substituted alkyl of from 1 to 8 carbon atoms; cycloalkyl or substituted cycloalkyl with 3 to 12 carbon atoms; aryl or substituted aryl; or an optionally substituted 5-membered or 6-membered heterocyclic radical which can additionally also be fused with a benzene ring, are prepared by reacting the corresponding carboxylic acid anhydride in the liquid phase with anhydrous hydrocyanic acid, at a temperature of between 50.degree. to 250.degree. C.

Process for the preparation of acyl cyanides

Acyl cyanides of the general formula ##STR1## in which R represents alkyl or substituted alkyl of from 1 to 8 carbon atoms; cycloalkyl or substituted cycloalkyl with 3 to 12 carbon atoms; aryl or substituted aryl; or an optionally substituted 5-membered or 6-membered heterocyclic radical which can additionally also be fused with a benzene ring, are prepared by reacting the corresponding carboxylic acid anhydride with an alkali metal cyanide or anhydrous hydrocyanic acid, at a temperature of between 50.degree. and 250.degree. C. and the resulting acyl cyanide is removed from the reaction medium by distillation, immediately after it has been formed.

In the preparation of perchloro-2,5-diaza-1,5-hexadiene by chlorination of N,N-dimethylaminoacetonitrile, the improvement which comprises in a first stage (a) chlorinating N,N-dimethylaminoacetonitrile or its hydrochloride at about 70.degree. to 80.degree. C. in a solvent, removing the solvent by distillation under chlorinating conditions until a bottom temperature of about 120.degree. to 160.degree. is reached, and after-treating the residual reaction at this temperature with chlorine, and in a second stage (b) chlorinating the resulting reaction mixture at a temperature from about 150.degree. to 220.degree. C. Advantageously the solvent in stage (a) is phosphorus oxychloride, the weight ratio of nitrile to solvent is about 1:3, the after-chlorination in stage (a) is carried out at a temperature from about 120.degree. to 140.degree. C., and stage (b) is carried out at a temperature from about 180.degree. to 210.degree. C. in a multi-stage bubble column cascade reactor operated with gas and liquid in counter-current.

Preparation of perchloro-2,5-diaza-1,5-hexadiene

A process for preparing monochloropinacoline (1-chloro-3,3-dimethyl-butan-2-one) by contacting a stoichiometric excess of pinacoline with chlorine at a temperature of -20.degree. to +70.degree. C.

1-Chloro-3,3-dimethyl-butan-2-one

A process for preparing a xylene which is fluorinated and chlorinated in the side chain, having the formula ##STR1## wherein X represents hydrogen or fluorine and

Preparation of trichloromethyl-trifluoro methyl-benzenes

Acyl cyanide compounds of the formula ##STR1## are prepared by reacting an acid halide of the formula ##STR2## with anhydrous hydrocyanic acid in the presence of a tertiary amine at a temperature between -70.degree. and +100.degree. C. R can be hydrocarbyl or substituted hydrocarbyl and X is halogen.

Process for the preparation of certain acyl cyanide compounds

N-chlorocarbonyl isocyanide dichloride is prepared by chlorinating methyl isocyanate and/or methyl carbamic acid chloride in solution in the presence of ultraviolet light at a temperature in the range of from 30.degree. to 120.degree.C. The temperature pattern during the reaction is controlled in relation to the concentration of methyl isocyanate in the reaction mixture such that low temperatures are maintained for high concentrations while high temperatures are maintained with low concentrations. Thus, when a temperature of from 30.degree.-40.degree.C is maintained during the reaction, the concentration of methyl isocyanate in the reaction mixture is substantially more than 50 percent; when the temperature is increased to 65.degree. to 75.degree.C, the concentration of methyl isocyanate is in the range of 50 percent to 10 percent; and when the temperature is increased above 75.degree.C, the concentration of methyl isocyanate is substantially below 10 percent.

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Leverkusen, Germany

Herbert Schwarz