Process for aqueous preparation of small size linear quinacridone

Application Number: 00102699
Application Date: 2000.02.25
Publication Number: 1266852
Publication Date: 2000.09.20
Priority Information: 1999/2/26 US 60/121863
International: C07D471/04;C09B48/00
Applicant(s) Name: Ciba Specialty Chemicals Holding Inc.
Inventor(s) Name: V. K. Mitiner
Patent Agency Code: 72001
Patent Agent: wang jingchao
Abstract A process for the preparation of a quinacridone of the formula: wherein A and B each independently represent a substituent selected from H, F, Cl, C1-C3alkyl and C1-C3alkoxy, including the steps of: (A) heating a reaction mixture containing (a) at least one unsubstituted and/or substituted 2,5-diarylamino-6,13-dihydroterephthalic acid and (b) about 3 to about 10 parts by weight of polyphosphoric acid per part of component (a) to a temperature of above about 125 DEG C to form a quinacridone melt; (B) treating the quinacridone melt resulting from (A) with about 1% to about 30% by weight, based on the weight of component (a), of concentrated sulfuric acid, to form a reaction mixture; (C) drowning the reaction mixture of (B) in a liquid in which the quinacridone is substantially insoluble; and (D) recovering the resulting quinacridone pigment.