The Hilton-davis Chemical Co.

Hilton Davis Co.

Wayne L Cook

Robert P Huth

Robert W Rebhahn

Salts of phenylazonaphthyl sulfonic acids useful as blue-red colorants for textile fabrics, cellulosic fibers and edible compositions are prepared by diazotizing aniline sulfonic acid and coupling the resulting diazo compound to a 1-hydroxynaphthalene mono- or disulfonic acid.

Edible compositions colored with

Physiologically acceptable cation salts of (2-alkoxy-4-sulfonyl-5-alkylphenyl)azo-1-hydroxynaphthalene sulfonic acids useful as blue-red colorants for textile fabrics, cellulosic fibers and edible compositions are prepared by diazotizing 2-alkoxy-4-sulfonyl-5-alkylanilines and coupling the resulting diazo compounds to a 1-hydroxynaphthalene mono- or disulfonic acid.

(2-alkoxy-4-sulfonyl-5-alkylphenyl)azo-1-hydroxynaphthalene sulfonic

The disodium salt of 1-[(6-methoxy-4-sulfo-3-methylphenyl)azo]-2-naphthol-6-sulfonic acid (FD and C Red 40), the disodium salt of 1-[(4-sulfophenyl)azo]-2-naphthol-6-sulfonic acid (FD and C Yellow 6), the trisodium salt of 1-[1-(4-sulfonaphthyl)azo]-2-naphthol-3,6-disulfonic acid (FD and C Red 2), the disodium salt of 2-[1-(4-sulfonaphthyl)azo]-1-naphthol-4-sulfonic acid (Carmoisine) and the sodium salt of 2-(2-quinolyl)-1,3-indanedione-sulfonic acid (D and C Yellow 10) are prepared and purified in high yield and in a high state of purity by subjecting their aqueous reaction mixtures to ultrafiltration through a membrane of such structure and under such conditions that the impurities are separated from the reaction mixtures, and the products are concentrated in high purity concentrates from which the products can be isolated directly by evaporation of the solvent.

Growing community of inventors

Cincinnati, OH, United States of America

Wayne L Cook