摘要:
4,4'-Dimethyl-6,6'-dichlorothioindigo is obtained in the stable crystal modification I, distinguished by the fraction angles (2 theta):lines of high intensity: 25.99; 27.26lines of moderate intensity: 10.27; 12.48; 22.39; 23.91; 24.82; 28.87,by oxidizing 3-hydroxy-4-methyl-6-chlorothionaphthene having a mean particle size of at most 20 .mu.m.