NUEVA MODIFICACION CRISTALINA DE C.I. PIGMENT YELLOW 191 Y PROCEDIMIENTO PARA SU PREPARACION

Procedimiento para la transformación de fases de C.I. Pigment Yellow 191, caracterizado porque sobre el compuesto de la Fórmula (1) o sobre un tautómero, un isómero cis-trans o un isómero cis- trans tautómero del compuesto de la Fórmula (1) se hace actuar un disolvente tomado entre el conjunto formado por N-metil-pirrolidona, dimetil-sulfóxido y dimetil-acetamida. 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.