| 摘要 |
PURPOSE: A method for preparing linear quinacridones having decrease a particle diameter and improve rheological properties and transparency is provided, which is obtained by heating (non) substituted 2,5-diarylamino-3,6-dihydroterephthalic acid and polyphosphoric acid with concentrated sulfuric acid. CONSTITUTION: The quinacridone of the formula, wherein A and B each independently represent a substituent selected from H, F, Cl, C1-C3 alkyl and C1-C3 alkoxy, is obtained by 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) immersing the reaction mixture of (B) in a liquid in which the quinacridone is substantially insoluble; and (D) recovering the resulting quinacridone pigment.
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