NEW MATERIAL:Compds. of formula I (wherein R 1 and R 2 are each a 5W9C alkyl or CH 3 and any one thereof is a 5W9C alkyl) and salts thereof.
EXAMPLE: Compd. of formula II (disodium 4-caproylamino-2-sulfophenylazo-2'- acetylamino-8'-hydroxyna-phthalene-6'-sulfonate).
USE: Monoazo acid dyes which dye wool and nylon fast red from acid baths and have excellent fastness to washing, sensitivity to formalin and solubility.
PREPARATION: 1,4-Diaminobenzene-3-sulfonic acid is acylated with caproic, enanthic, caprylic, pelargonic or capric anhydride or an acid halide thereof. The acylated product is diazotized and then coupled with acetyl-γ-acid.