Di:bromo-anthra-quinone pigment prepn. by environmentally friendly method

摘要

Prepn. of 4,10-dibromo-anthraquinone pigment (I) comprises (a) wet milling coarsely crystalline crude (I) to the required fineness in aq. medium in a stirred ball mill with a power of over 2.5 kW/l and stirrer peripheral velocity of over 12 m/s, using milling balls with a dia. of less than 1.0 mm; and (b-1) isolating (I) from the suspension or (b-2) finishing the pre-pigment from wet milling by high temp. treatment in an aq. or aq.-organic medium or liquid aromatic cpd. and then isolating (I).