Bayer Aktiengesellschaft

Hermann D Krall

Bernd Gallenkamp

Herbert Schwarz

Novel lactic acid silyl esters of the formula ##STR1## in which R represents alkyl or aryl, are obtained by a new process which comprises reacting a lactic acid of the formula ##STR2## with a chloromethylsilane of the formula ##STR3## in which R has the meaning indicated above, in the presence of a tertiary amine and, if appropriate, in the presence of an additional diluent, at temperatures between 50.degree. and 120.degree. C.

Process for the preparation of lactic acid silyl esters

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.

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Meerbusch, Germany

Hermann D Krall