Purification of metal complex pigments - by treatment with mineral acid

摘要

Prodn. of pure metal complex pigments of formula (I) is carried out by treating impure (I) with a mineral acid, adding H2O (if necessary) to ppte. the product and separating, neutralising and isolating the product: (where R, R1, R2 and R3 are H, 1-4C alkyl or alkoxy, Cl, Br, CF3 or Ph; M is Cu, Co or Pref. Ni; Z is NH, S or O A- is an anion). The process allows crude products produced by the process of DT2357830 to be converted into a pure form suitable for direct use as a pigment in lacquers and plastics. Laborious Zn halide adduct formation using expensive aprotic solvents is avoided (cf. DT2357830).