| 摘要 |
4,4',7,7'-Tetrachlorothioindigo pigments of high color strength are prepared by oxidizing 3-hydroxy-4,7-dichlorothionapthene or a mixture of tetrachlorothioindigo and hydroxydichlorothionaphthene in aqueous alkaline suspension with a salt of a nitro-aromatic sulfonic acid, in the presence of a high-boiling, water-immiscible or only slightly water-miscible aromatic liquid, at from 40 DEG to 100 DEG C., and heating the organic suspension to 110 DEG -180 DEG C. Pigmentary forms of tetrachlorothioindigo are isolated which give deep colorations of high brilliance when reduced with white pigments.
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