GB703497A - Improvements relating to the neutralization of sulphonated organic products - Google Patents

Abstract

Synthetic detergents substantially free from inorganic salts are prepared from an acid mixture containing an organic sulphonic acid or sulphuric acid ester yielding a detergent on neutralization, and excess sulphonating agent, by establishing a solvent solution containing water and a water-miscible aliphatic alcohol, feeding thereinto a stream of the acid mixture and a separate stream of neutralizing agent while controlling the reaction temperature so that it does not exceed 150 DEG F., the amount of alcohol being small but sufficient to cause the formation of two immiscible liquid layers and the rate of feed of the neutralizing agent being so proportioned to the rate of feed of the acid mixture that the resultant reaction mixture remains substantially neutral, the amount of solvent solution being such that one of the liquid layers contains substantially all of the neutralized detergent acid or ester dissolved in the organic solvent and the other liquid layer contains substantially all of the neutralized excess sulphonating agent dissolved in the water, and separating the two liquid layers. In general, a solids concentration of about 15-40 per cent. of the water is employed. There may thus be neutralized sulphuric acid esters of monoglycerides of higher fatty acids and sulphated higher fatty alcohols. The process may be operated batchwise or continuously. Suitable apparatus is illustrated (not shown). In examples (1) and (2): an acid mixture of sulphuric esters of monoglycerides of coconut oil fatty acids and sulphuric acid and an aqueous solution of ammonia are both gradually added to a stirred mixture of water and ethanol containing a little ammonia and the reacted mixture allowed to settle whereupon a lower aqueous layer of ammonium sulphate is separated from the upper 50 per cent. alcoholic solution of detergent which may be used in shampoos, cosmetics or dental creams; (3) the same acid mixture and aqueous caustic soda are similarly run into a stirred mixture of water and isopropanol and the resulting alcoholic upper layer distilled to separate the alcohol from the neutralized detergent. Specification 666,206 is referred to.