GB811893A - Aldehyde monoperacylates - Google Patents

Abstract

The interconversion of the monoperacylate of a C2-6 aliphatic aldehyde and a mixture of the corresponding peracylic acid and aldehyde is effected in the liquid phase at a temperature of from - 50 DEG to 200 DEG C., preferably 10 DEG to 120 DEG C., in the presence of a basic catalyst. Suitable catalysts include organic bases such as pyridine, ammonia and the alkali metal and alkaline earth metal salts of weak acids, especially sodium acetate, the latter preferably in a concentration of from 0.005 to 2.0 per cent by weight of the total reaction mixture. Organic solvents may be used including ketones such as acetone, methyl ethyl ketone and cyclohexanone, esters such as ethyl and n-butyl acetate or organic acids such as acetic. The reaction may be used either for preparing aldehyde/peracyclic acid mixtures from aldehyde monoperacylates, preferably peracetates or perpropionates, especially acetaldehyde monoperacetate, or for preparing aldehyde monoperacylates from the corresponding acid/aldehyde mixture, preferably comprising peracetic or perpropionic acid with acetaldehyde or propionaldehyde. The aldehyde monoperacylate or the aldehyde and/or the peracylic acid may be removed from the reaction mixture, preferably continuously, as the reaction proceeds, by any suitable known procedure, such as fractional distillation, solvent extraction or chemically. Alternatively the reaction mixture may itself be used for further reactions without isolating the products, e.g. for the epoxidation of olefines. The process may be used as part of a purification procedure for other compounds, such as in the removal of aldehyde or peracylic acid from aldehyde oxidates by distillation or extraction to obtain pure monocarboxylic acids. Examples illustrate the use of cupric and sodium acetates in the conversion of acetaldehyde and peracetic acid in acetic acid solution. Comparative examples use no catalyst and sulphuric acid catalyst. The Provisional Specification refers also to the use of acidic catalysts such as acidic salts of metals and organic and inorganic acids stronger than acetic acid, e.g. ferric chloride, formic acid, sulphuric acid and perchloric acid.