Boyd A Keys

US Patent:

55084516, Apr 16, 1996

Filed:

Jul 7, 1994

Appl. No.:

8/271804

Inventors:

Apurba Bhattacharya - Corpus Christi TX
Boyd A. Keys - Corpus Christi TX

Assignee:

Hoechst Celanese Corporation - Sommerville NJ

International Classification:

C07D31124

US Classification:

549402

Abstract:

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.

US Patent:

49683527, Nov 6, 1990

Filed:

Apr 28, 1988

Appl. No.:

7/187623

Inventors:

Boyd A. Keys - Providence RI
John T. Ouderkirk - Westerly RI

Assignee:

Hoechst Celanese Corporation - Somerville NJ

International Classification:

C09B 6706
C09B 6720
C09B 6722

US Classification:

106494

Abstract:

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.