Ciba-geigy Corporation

Bilge Gulec

Michael Reisinger

Werner Surber

Klaus Ruf

A process for the preparation of a nitrile of formula ##STR1## wherein R is hydrogen, C.sub.1 -C.sub.4 alkyl or phenyl, by reaction of an aldehyde of formula ##STR2## wherein R is as defined above, with hydroxylamine sulfate and subsequent dehydration, which process comprises carrying out the reaction in propionic acid in the presence of a salt of propionic acid by heating to an external temperature in the range from 140.degree. to 165.degree. C., preferably from 150.degree. to 160.degree. C., for 2 to 6 hours, preferably for 3 to 5 hours, under atmospheric pressure, and simultaneously distilling the mixture of propionic acid and water from the system until a solution forms, and thereafter removing the mixture of propionic acid and water at 100.degree.-130.degree. C., preferably 110.degree.-120.degree. C., by vacuum distillation, and then isolating the resultant nitrile by standard procedures.

Preparation of aromatic nitriles

The present invention relates to the preparation of bisazo pigments by reaction (a) of 2 mol of an azocarbonyl chloride of the formula ##STR1## with 1 mol of a diamine of the formula ##STR2## by reaction (b) of one mole of a bis(azocarbonyl chloride) of the formula ##STR3## with 2 mol of an amine of the formula ##STR4## which comprises carrying out the reactions (a) or (b) in the presence of 1,2,3-trimethylbenzene or anisole as the solvent.

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Basel, Switzerland

Bilge Gulec