Patent GB-714083-A (GB)
Title: Process for preparing metal phthalocyanines
IPC: C09B47/06
Filed: 1951-10-29
Abstract: In a process for preparing a metal phthalocyanine which comprises heating in an inert organic liquid diluent, at phthalocyanine-forming temperature a reaction mixture containing an organic phthalocyanine intermediate of the class consisting of aromatic ortho-dicarboxylic acids, their anhydrides, acid halides, esters, ammonium salts, mono-and diamides, imides and imino imidines, esters and ammonium salts of the monoamides, the corresponding ortho-cyanocarboxylic acids and their esters, amides and ammonium salts and corresponding o , <\>ao -polyhalo-o o-dimethyl aromatic compounds and o -halo-O-methyl aromatic nitriles, any additional nuclear substituents in such intermediates being non-reactive under the reaction conditions, a nitrogen donor of the class consisting of urea, biuret, guanidine, guanidyl-urea, dicyandiamide and cyanuric acid, and a phthalocyanine-forming metal-yielding reagent in the presence of a catalyst promoting phthalocyanine formation and containing an element of Group V or VI of the Periodic Table of atomic number from 15 to 92, there is included in the reaction mixture an amount not substantially less than 25 per cent and preferably not substantially more than 100 per cent of the weight of the said organic phthalocyanine intermediate, of a salt of a phosphoric acid with an alkali metal, an alkaline earth metal, magnesium, or the ammonium radical.  The salt of a phosphoric acid may be acid or neutral salts and include for example ortho-phosphates, pyrophosphates, meta-phosphates, poly-meta-phosphates (e.g. tri-, tetra-, and hexa-meta-phosphates) and polyphosphates of sodium, potassium, ammonium, calcium, barium, strontium, or magnesium. Several such phosphates are specified and polyphosphates obtained by fusion of alkali metal hexametaphosphates with alkali metal pyrophosphates may also be used.  The phthalocyanine intermediates are preferably of the benzene series and may contain non-reactive substituents e.g. chlorine, bromine, nitro, alkyl, aryl, condensed nuclear aryl, alkoxy, aryloxy, alkyl-thio or aryl thio radicals, or acyl groups. Suitable metal-yielding reagents are those containing polyvalent metals and their salts, such as copper, aluminium, magnesium, nickel, iron, cobalt, zinc, tin, vanadium, or chronium; suitable compounds include the chlorides, bromides, sulphates, nitrates, and oxides. Suitable reaction temperatures are generally 150 DEG  to 210 DEG C. Specified inert diluents are trichlorobenzene, dichlorobenzene, naphthalene and its chlorinated derivatives, quinoline, benzophenone, and nitrobenzene.  The preferred catalysts are molybdates such as alkali metal or ammonium molybdates, phospho-molybates, or tungsto-molybdates and suitable amounts of such catalysts are from 0.1 to 2 per cent of the weight of the total reaction mixture.  In examples: (1) phthalic anhydride is heated with urea in trichlorobenzene in the presence of ammonium molybdate and monosodium dihydrogen phosphate, and a slurry of anhydrous aluminium chloride in trichlorobenzene added; after refluxing the mixture for 6 hours at 200 to 205 DEG C.  A slurry of urea in trichlorobenzene is added and the same temperature is then maintained for 5 hours; chloroaluminium phthalocyanine being recovered from the mixture.  Instead of monosodium phosphate, disodium hydrogen phosphate, trisodium phosphate, calcium phosphate, magnesium pyrophosphate or magnesium ammonium phosphate may be used; (2) chloroaluminium phthalocyanine is obtained by heating a mixture of phthalamide, urea, aluminium chloride, ammonium molybdate and diammonium phosphate in tetrachlorobenzene and then adding a slurry of urea in trichlorobenzene and heating the mixture at 200-205 DEG C for 5 hours. Instead of phthalamide, phthalimide or o-cyanobenzamide may be used; (3) copper hexadecachloro-phthalocyanine is obtained by heating a mixture of tetrachlorophthalic anhydride, urea, ammonium molybdate, cuprous chloride and disodium hydrogen phosphate, trisodium phosphate, or monosodium phosphate; (4) nickel phthalocyanine is obtained from phthalic anhydride, urea, nickel chloride, ammonium molybdate and trisodium phosphate in trichlorobenzene; instead of trisodium phosphate there may be used monosodium dihydrogen phosphate or sodium tripolyphosphate; (5) magnesium phthalocyanine is obtained by heating in trichlorobenzene, a mixture of phthalic anhydride, urea, magnesium oxide, ammonium molybdate and sodium tripolyphosphate (sodium meta-phosphate or magnesium phosphate).  It is stated that metallic copper or other copper salts may be used as metal donors instead of cuprous chloride, and that aluminium acetate, magnesium nitrate or chloride and nickel nitrate may be used to replace aluminium chloride, magnesium oxide, and nickel chloride respectively.  Other specific phthalocyanine-forming intermediates mentioned are phthalyl chloride, o , <\>ao -polychloro- or polybromo-o-dimethyl aromatic compounds e.g. o -tetra, -penta, or -hexachloro-o-oxylene, and o -chloro- or -bromo-o-methyl aromatic nitriles e.g. o -mono, -di- or -trichloro or bromo-O-tolunitrile. U.S.A.  Specifications 2,213,726, 2,214,477, 2,276,598 and 2,410,301 are referred to.