Bayer Aktiengesellschaft

Siegfried Bohm

Karlfried Wedemeyer

Hans-Josef Buysch

Heinrich Krimm

Alfons Klein

Helmut LeBlanc

An improved process for the preparation of 2,6-xylidine by amination of 2,6-dimethylphenol in the vapor phase with ammonia in the presence of an aluminum oxide catalyst is disclosed. According to the invention, particular amination conditions are chosen to effect high yields of the desired product. These conditions include a temperature of 360.degree. to 460.degree. C. and a minimum molar ratio of ammonia to 2,6-dimethylphenol which corresponds to the general formula ##EQU1## wherein X represents the minimum molar ratio of ammonia to 2,6-dimethylphenol,

Process for the preparation of 2,6-xylidine

In a process for the preparation of dimethyl carbonate by reacting methanol with phosgene and/or methyl chloroformate, the improvement wherein the reaction is carried out in the presence of an aqueous alkali metal hydroxide solution and in the presence of an inert, water-immiscible organic solvent, at a temperature in the range from -20.degree. C. to +40.degree. C.

Process for the preparation of dimethyl carbonate

A process for the preparation of a 4-aminodiphenyl amino derivative which comprises:

Process for the preparation of 4-amino-diphenylamines

A process for the preparation of a-phenoxy-benzaldehyde which comprises contacting the 3-phenoxy-benzyl alcohol of the formula ##STR1## wherein R.sup.1 and R.sup.2 are identical or different and represent hydrogen or halogen with an aqueous solution of a dichromate in the presence of aqueous sulphuric acid at a temperature in the range of 50.degree. to 125.degree. C. The 3-phenoxy-benzaldehyde can be in a mixture of other organic compounds such as obtained by hydrolyzing a 3-phenoxy toluene chlorinated in the side chain at a temperature of 140.degree.-210.degree. C. under pressure.

Process for the preparation of 3-phenoxy-benzaldehydes

A process for the preparation of azodicarbonamide by oxidation of hydrazodicarbonamide in an aqueous suspension containing hydrogen peroxide wherein the reaction is carried out in the presence of iodine at a temperature between 50.degree. and 95.degree. C. while the reaction mixture has a pH ranging from 1.0 to 5.0.

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Cologne, Germany

Siegfried Bohm