Reference

Quinacridone and its derivatives

Quinacridone and its derivatives. Gerson, Herman; Santimauro, John Francis; Lerner, Lawrence Robert (Harmon Colors Corp., USA). U.S. US 4064129 20 Dec 1977, 8 pp. (English). (United States of America). CODEN: USXXAM. CLASS: IC: C09B048-00. NCL: 260279000QA. APPLICATION: US 76-724150 17 Sep 1976. DOCUMENT TYPE: Patent CA Section: 40 (Dyes, Fluorescent Whitening Agents, and Photosensitizers) Quinacridone (I) [1047-16-1] and its 2,9-dimethyl- [980-26-7] and 2,9-dichloro- [3089-17-6] derivs. are prepd. in high purity and yield by heating the corresponding 2,5-bis(arylamino)terephthalic acid in the presence of a sulfonic acid or HClO4 catalyst in a 2-phase liq. system comprising ethylene glycol (II) [107-21-1] and a H2O- and II-immiscible org. solvent at a temp. sufficient to remove the by-product H2O from the reaction by vaporization. Thus, I was prepd. in 94.4% yield by using II-perchloroethylene [127-18-4] solvent system and p-toluenesulfonic acid monohydrate [6192-52-5] as catalyst with 2,5-dianilinoterephthalic acid [10109-95-2] as starting material.

Studies of the crystal structure of 2,9-dimethylquinacridone

Studies of the crystal structure of 2,9-dimethylquinacridone. Lincke, G. (Fachhochsch. Niederrhein, Krefeld D-415, Fed. Rep. Ger.). Congr. FATIPEC, 17th(3), 303-26 (German) 1984. CODEN: FAPVAP. ISSN: 0430-2222. DOCUMENT TYPE: Journal CA Section: 41 (Dyes, Organic Pigments, Fluorescent Brighteners, and Photographic Sensitizers) Section cross-reference(s): 75 The crystal structure of 2,9-dimethylquinacridone (I) [980-26-7] pigment, which affects its chem. and technol. properties, was detd. The close packing principle of A.I. Kitaigorodski (1979), the F-face theory of P. Hartman and W. Perdok (1955), and principles of smectic phases were considered. I mols. are stacked like rolls of coins, and are H-bonded by lateral NH-CO group dipoles to give 2-dimensionally bound [so-called (001)] faces. Pigment finishing produces these faces with the proper particle size and stabilizes the mol.