GB1054044A - - Google Patents

Abstract

1,054,044. Perimidone-6,7-dicarboxylic imide pigments; printing inks. BADISCHE ANILIN- & SODA-FABRIK A.G. Oct. 11, 1963 [Oct. 12, 1962], No. 40144/63. Headings C4A and C4P. [Also in Division C3] The invention comprises pigments having the general formula in which R is a hydrogen atom, an aliphatic radical or an aromatic radical. The aliphatic radicals preferably have 1-6 carbon atoms and the aromatic radicals are preferably benzene or naphthyl derivatives; all of these radicals may have substituents, e.g. hydroxyl or halogen. The pigments are prepared from 4,5-diaminonaphthalic anhydride, by conversion directly in a urea melt at 80- 200‹ C., or by treatment with phosgene in a solvent at 50-250‹ C. followed by reaction with ammonia in aqueous solution or with an amine alone or in an organic solvent, under a wide range of temperatures. The phosgene treatment may be reversed with the ammonia or amine treatments, thus according to which sequence of reactions is used the intermediate product is either 4,5-diamino-naphthalic imide of formula or perimidone-6,7-dicarboxylic anhydride of formula The 4,5-diamino-naphthalic anhydride used as starting material may be obtained by reduction of the dinitro compound, also the 4,5-diaminonaphthalic imide may be obtained by reduction of its corresponding dinitro compound. Instead of the anhydride being used as starting material, naphthalic acid itself may be used as this is easily converted to its anhydride. In the above reactions in which ammonia or amines are used, formamide may be employed instead at temperatures of 100-195‹ C. In the conversion of compounds of Formula III to those of Formula IV anhydrous media are preferably used, especially acid amides or nitrobenzene. The pigments produced by the process may be subjected to conventional grinding, sulphuric acid and swelling treatments to produce the required partial size. In Example 7 perimidone-6,7- dicarboxylic imide is ground with alumina trihydrate and linseed oil varnish and used as a printing ink, and in Example 8 the same pigment is ground with nitrocellulose, dibutyl phthalate and a mixture (9: 1) of ethanol and ethyl glycol to form a copper plate printing ink.