Method for making metal phthalocyanine pigments

Metal phthalocyanines are made by heating a phthalocyanine-forming material, metal and nitrogen donors, in an inert solvent in presence of a catalyst comprising (a) at least one freshly-prepared anion-free hydrated gel of a metallic or semi-metallic oxide, or (b) at least one hydrated material at least partially soluble in said nitrogen donor and being the product obtained by digesting a metallic or semimetallic oxide with a mineral acid, or (c) at least one hydrolysable compound having the general formula E-(-OR)x, where E is an element having an atomic number of at least 28, is capable of forming an oxide gel, and is selected from Groups IV, V, VI, or the rare earth elements of the Periodic Table, R is the residue of an organic compound attached to E through at least one oxygen atom, and x the valence of E, said catalyst being present in an amount at least sufficient to provide satisfactory yields of pigment and preferably in an amount of at least about 1 mol. catalyst, computed as metallic ions, for every 4 mols. of the phthalocyanineforming material. Catalyst (a) may be hydrated titanium or zirconium dioxide gel, catalyst (b) may be the same dioxides digested with sulphuric acid, hydrohalides, perchloric, or phosphoric acids, and catalyst (c) may be compounds of the formula E-(-OR)x, where E is titanium or zirconium, R is alkyl, aryl, alkaryl, or aralkyl (or substituted products thereof), and x is the valence of E, e.g. tetramethyl titanate or zirconate, or tetrabutyl titanate. The metal donor may be copper chloride or nitrate, and the phthalocyanine-forming material may be tetrachlorphthalic anhydride. In examples, tetrachlorphthalic anhydride is heated with trichlorbenzene, urea, cupric nitrate or chloride, and (1) titanium or zirconium dioxide gel, freshly prepared, (2) the product obtained by digesting either of said oxides with sulphuric acid, or (3) tetramethyl titanate or zirconate, or tetrabutyl titanate.