Patent AT-E400617-T1: [Translated] GAMMA CRYSTAL MODIFICATION OF C.I. PIGMENT YELLOW 191 AND METHOD FOR PRODUCING IT

Phase transformation of C.I. Pigment Yellow 191 involves the effect on it, its tautomers, cis-trans isomers or cis-trans isomer tautomers of diethylene glycol dimethyl ether. Phase transformation of C.I. Pigment Yellow 191 of formula (I) involves the effect on it, its tautomers, cis-trans isomers or cis-trans isomer tautomers of diethylene glycol dimethyl ether. [Image] An independent claim is produced for the gamma modification of (I) or its isomers or tautomers, this modification optionally containing sodium or chloride ions or water molecules in its crystal lattice and having an X-ray powder diffractogram with characteristic lines. Gamma-modification is given by 2theta d/d/relative intensity values of 4.77/18.49/100; 10.08/8.67/27; 11.79/7.50/29; 13.39/6.60/20; 14.34/6.17/21; 16.71/5.30/22; 18.23/4.86/30; 21.22/4.18/29; 22.67/3.91/21;23.10/3.84/20 and 25.79/3.45/36 respectively.