Hoechst Celanese Corporation

Boyd A Keys

Apurba Bhattacharya

John T Ouderkirk

A process for preparing a dialkali metal cromoglycate which comprises (1) condensing a hydroxy substituted ketone with a condensing agent in the presence of a base material and an organic solvent; (2) subjecting the condensed material to ring-closure conditions, first in the presence of an alkali metal alkoxide and a suitable organic solvent, then followed by the addition of substantially dry mineral acid and a suitable organic solvent; and (3) hydrolyzing the ring-closed material in the presence of a base material and a suitable organic solvent to form said cromoglycate.

Process for the preparation of dialkali metal cromoglycates

Diaryl pigments having excellent dried ink transparency and improved process heat stability are prepared by carrying out the coupling of a bisdiazotized substituted 4,4' diaminobiphenyl with acetoacetanilides and/or pyrazolinones in the presence of an added quantity of one or more substituted aromatic amines containing at least one sulfonic or carboxylic acid substituent, or their salts. The pigments exhibit improved tolerance to variations in drying temperatures and to high drying temperatures, and have improved transparency when present in dried ink formulations.

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Providence, RI, United States of America

Boyd A Keys