PROCESS FOR THE PREPARATION OF CYANO AZO DYES

摘要

The ortho-cyano azo of formula (I) is prepared by reacting the compound of formula (II) with zinc cyanide using cupric sulfate or cupric acetate catalyst in the presence of polar nonproton solvent. In formula, R is C1-4 alkyl group. Pref. the solvent is N,N-dimethylformaldehyde. The mole ratio of the cupric compound to compound (II) is 3-15 mol%. The dye has an exellent dyeability and color fastness, and is useful for dyeing synthetic fibers.