GB340939A - Improvements in or relating to the manufacture of aliphatic acids and esters - Google Patents

Abstract

Aliphatic acids and their esters are prepared by the reaction of alkyl ethers with carbon monoxide in the presence of non-acidic catalysts known to promote the synthesis of aliphatic acids from aliphatic alcohols and carbon monoxide. Suitable catalysts are substances which are, or are capable of forming, acetates which split off acetic acid at temperatures under 450 DEG C., e.g. copper oxide, tin oxide, lead oxide, copper acetate, zinc oxide, zinc acetate, zinc methylate, aluminium methylate and tin methylate, or mixtures thereof with each other or with more basic materials such as potassium or sodium acetate. Alkali methylates may also be added to the catalyst. The other conditions of the process are the same as those described in the parent Specification. If sufficient water vapour is present in the reaction mixture, the aliphatic acid preponderates in the product, while in the presence of little or no water the ester is the main product. The esters may be saponified to the acid by the processes described in Specifications 283,989 and 284,582, [both in Class 2 (iii), Dyes &c.]. According to an example, carbon monoxide and dimethylether are passed under a pressure of 100-200 atmospheres through a copper-lined reaction chamber filled with granules of zinc oxide or tin oxide or of a mixture of zinc oxide or tin oxide with sodium methylate; methyl acetate condenses from the products. In the remaining example, the same process is conducted in the presence of steam, when acetic acid condenses.