Synthesis of substituted amido copper phthalocyanine (pc) derivatives for improved pigment application performance

Substituted amido copper phthalocyanine (CuPc) derivatives are being investigated as additives in pigment systems. Propylamido, dodecylamido and octadecylamido copper phthalocyanine have been prepared by reaction of the corresponding amine hydrochloride and the mono (carboxamide) of copper phthalocyanine in a melt reaction. The carboxamide of CuPc was prepared by reaction of phthalic acid and trimellitic acid in a urea melt; reagents were selected to maximize the mono-substituted product. The mono (carboxamide) of CuPc as prepared therefore contained CuPc and a statistical mixture of other CuPc carboxamides; however, the formation of the alkyl derivatives allowed purification by high-temperature thin layer chromatography, which gave good separations, and characterization with MALDI-TOF mass spectrometry. Initial investigations show that these alkyl amido CuPcS, when used in CuPc pigment compositions for paints improve the dispersion rheology and dispersibility/colouring strength.