GB1492607A - Process for the preparation of carboxylic acids and/or derivatives thereof - Google Patents

Abstract

1492607 Preparation of carboxylic acids and their derivatives SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ BV 3 Dec 1974 [25 Jan 1974] 52226/74 Heading C2C In a process for the preparation of carboxylic acids and/or derivatives thereof by contacting carbon monoxide with an olefinically unsaturated compound, an alkyne, an alcohol, an ether and/or an ester, in the presence of water-optionally in addition to another nucleophilic compound with one or more reactive hydrogen atoms and a catalytic quantity of a nickel (II) and/or cobalt (II) bromide or iodide, impurities of free and/or bound halogen present in the catalyst feed, which may give rise to corrosion, are rendered innocuous and/or removed, before the said feed, which contains fresh and/or used catalyst in a liquid aqueous medium, is passed into the reaction zone. The impurities are in particular free bromine or iodine and polybromides or polyiodides. The catalyst solution may be treated with a metal or alloy, e.g. with nickel shavings when a nickel catalyst is used, or it may be treated with an absorbent, e.g. active carbon, silica, alumina, clay and other porous materials. The treatment may be monitored quantitatively by titration with thiosulphate or qualitatively by the colour reaction with starch/water. In examples, a mixture of C 15 -C 18 alpha olefins is reacted with carbon monoxide in the presence of aqueous nickel iodide to produce a mixture of C 16 -C 19 carboxylic acids. Other processes mentioned are the carbonylation of olefins in the presence of alcohols, mercaptans, ammonia, amines or carboxylic acids to produce carboxylic esters, thioesters, amides or anhydrides, and the carbonylation of alcohols to produce carboxylic acids.