Patent ID: 6465652
Filing Date: 2002-10-15
Classification: C09B

Abstract:
A process of forming a polymorphic forming of 2,9-dichloroquinacridone, the process comprising reacting 2,5-di(4-choroanilino)terephthalic acid with concentrated sulphuric acid of a concentration of 90 to 95% at a temperature between 100Â° C. and 130Â° C., wherein the obtained polymorphic form of 2,9-dichloroquinacridone has an x-ray diffraction pattern including reflections corresponding to the following interplanar spacings and double glancing angles (Grade 2&thgr;):d-Value(Angstroms)Grade 2&thgr;16.735.36.3314.05.8215.25.3616.54.6219.24.1821.33.8822.93.8123.33.6424.43.5225.33.3526.63.1927.93.0829.02.8031.92.6833.42.4536.72.3937.62.2839.4.