Patent GB-1342788-A (GB)
Title: Process for the preparation of a naphthalene monocarboxylic  acid and or a naphthalene dicarboxylic acid
IPC: B01J27/08
Filed: 1971-04-19
Abstract: 1342788 Preparation of naphthalene mono- and di-carboxylic acid TEIJIN Ltd 19 April 1971 [17 Feb 1970 (2)] 21992/71 Heading C2C [Also in Division B1] Naphthalene monocarboxylic acid(s) and/or naphthalene dicarboxylic acid(s) is prepared by a process which comprises contacting, at a temperature of from 70‹ to 170‹ C., monomethylnaphthalene(s) and/or dimethylnaphthalene(s) in solution in a solvent comprising acetic acid with molecular oxygen in the presence of a catalyst composition comprising (A) at least one cobalt compound which is soluble in the solvent, (B) at least one manganese compound which is soluble in the solvent and (C) bromine or a compound thereof which releases bromine when contacted with the solvent, the components (A), (B) and (C) being present in specified relative proportions such that, whilst both of components (A) and (B) cannot be bromide alone, either of components (A) and (B) may comprise a bromide in which case component (C) may be absent. The solvent may be anhydrous acetic acid or aqueous acetic acid which preferably contains less than 20 weight per cent of water. At least 2.5 parts by weight  of acetic acid and from 0.03 to 0.10 parts by weight of total catalyst components (A), (B) and (C) are present per part by weight of methylnaphthalene to be converted. Exemplified compounds of cobalt and manganese are oxides. hydroxides, carbonates, basic carbonates, bromides and salts of aliphatic, alicyclic and aromatic mono- and di-carboxylic acids, for example formates, acetates, propionates, butyrates, oxalates, maleates, benzoates, phthalates, isophthalates, terephthalates, naphthalene mono- and di-carboxylates and naphthenates; exemplified bromine compounds are hydrobromic acid, ammonium bromide, metal bromides, for example sodium bromide and potassium bromide, and organic bromine compounds, for example bromoacetic acid, benzyl bromide and bromonaphthalene. Exemplified methylnaphthalenes are 1-methyl; 2-methyl; 1,2-dimethyl; 1,3-dimethyl; 1,4-dimethyl; 1,5-dimethyl; 1,6-dimethyl; 1,7-dimethyl; 1,8-dimethyl; 2,3-dimethyl; 2,6-dimethyl; and 2,7-dimethylnaphthalene. A mixture of two or more such methylnaphthalenes may be used, for example a commercially available mixture also containing, as impurities, naphthalene, biphenyl and trimethylnaphthalene. The molecular oxygen may be supplied in the form of either pure oxygen or a gaseous mixture comprising oxygen and an inert gas, for example nitrogen, helium or argon; air may be used. The contacting may be effected continuously or in batchwise manner. The reaction mixture may be recycled after removal therefrom of water and naphthalene carboxylic acid reaction product. Examples relate to the oxidation, to the corresponding naphthalene carboxylic acid(s), of 1-methylnaphthalene (Examples 21 and 23 to 32); 2-methylnaphthalene (Example 22); 1,4-dimethylnaphthalene (Example 1); 2,6 - dimethylnaphthalene (Examples 8 to 17 and 34 to 38); a mixture of (unspecified) dimethylnaphthalenes (Examples 2 to 7 and 18 to 20); and a mixture containing 1-methylnaphthalene, 2-methylnaphthalene, various dimethyhlaphthalenes and, as impurities, 1- ethylnaphthalene, 2-ethylnaphthalene, biphenyl and acenaphthene (Example 33) in the presence of catalysts comprising components (A), (B) and (C) variously selected from the relevant compounds listed. Numerous comparative examples are also given.