GB777961A - Improvements relating to the desulphurisation of phenolic materials - Google Patents

Abstract

Phenolic materials are desulphurized by passing them in the vapour phase with hydrogen over a metal oxide or metal salt catalyst at an elevated temperature whereby sulphur is removed from sulphur compounds present as impurities and is converted to hydrogen sulphide. Catalysts specified are mixtures of oxides of cobalt and molybdenum, or cobalt molybdate, either alone or incorporated with a support such as alumina. During the desulphurization, the catalyst reacts with hydrogen sulphide so that the oxygen is partly replaced by sulphur; it is stated that this results in increased catalyst activity. The catalyst may be regenerated after long use by conventional means. The desulphurization may be effected by passing the vaporized phenolic material with hydrogen at usually less than 3 atmospheres absolute pressure and at 200 DEG to 300 DEG C. over the catalyst and condensing the desulphurized phenolic material. Residual hydrogen sulphide may be removed from the product by air blowing. The gases from the desulphurization containing hydrogen sulphide and excess hydrogen may be treated by conventional means to remove hydrogen sulphide and the purified hydrogen is then recycled. In examples, xylenols and o- and m-cresols are desulphurized by passage with hydrogen at atmospheric pressure over a catalyst of cobalt molybdate on alumina.