GB631001A - Process for the production of organic carboxylic acid anhydrides - Google Patents

Abstract

Carboxylic acid anhydrides are produced by heating compounds containing olefinic or aromatic unsaturation with carbon monoxide and carboxylic acids. Olefinic hydrocarbons of the formula RR1C = CR2R3, where R, R1, R2 and R3 are hydrogen, alkyl, aryl or aralkyl radicals or aromatics such as naphthalene are suitable. With an acid R4COOH, the olefins yield isomeric anhydrides CHRR1CR2R3COO COR4 and CHR2R3CRR1COOCOR4. With carbon monoxide and propionic acid, ethylene gives propionic anhydride, while propylene and butylene give corresponding mixed anhydrides. Ethylene with formic or acetic acid yields mixed formic or acetic propionic anhydride; propylene and butyric acid gives butyric anhydride; and isobutylene and isovaleric acid, isovaleric anhydride. Adipic, benzoic and oleic acids are similarly employed. Hydrocarbon mixtures such as cracking or dehydrogenation products, diolefins, cyclo-olefins and substituted olefins are generally applicable. Substituent groups unreactive with the anhydride produced may be present. Inert gases, e.g. nitrogen or methane, may be present, and a minor quantity of carbon dioxide may be used to suppress hydrogen production by the water-gas reaction if the reactants are not moisture free. Pressure is preferably above atmospheric, e.g. 25-2000 atm. or above, especially 300-1500 atm., at temperatures of about 200-500 DEG , especially 275-400 DEG C. Suitable catalysts include salts, oxides, hydroxides, metals and carbonyls, particularly nickel carbonyl or substances yielding it. Copper, cobalt and manganese compounds, if desired on inert supports, are also specified. The reaction products of olefins, carbon monoxide, and water in the presence of nickel carbonyl, obtained as in Specification 630,279, may be used as starting materials if the amount of water present is not sufficient to hydrolyse the anhydride formed or the anhydride may be formed directly from olefin, carbon monoxide and water, the water first being converted to acid. For vapour phase reaction, a reactor containing absorptive material such as silica gel or charcoal may be used. In examples, ethylene, propylene or naphthalene is reacted with carbon monoxide and propionic or acetic acid, nickel carbonyl, formate or propionate or cobalt propionate being added as catalyst.