Patent GB-693779-A (GB)
Title: Improvements relating to the neutralization of acid sulphonation products
IPC: C07C303/44
Filed: 1950-12-29
Abstract: Acid sulphonation products substantially free from unsulphonated hydrocarbons and containing excess sulphonating agent and organic sulphonic acids or sulphuric acid esters which on neutralization yield water-soluble surface-active compounds useful as washing, wetting, emulsifying or frothing agents or detergents, are neutralized by preparing a liquid vehicle containing a neutralizing agent dissolved or suspended therein and consisting of two liquid phases, one of which is a water-miscible organic liquid boiling at less than 100 DEG  C. and in which the neutralized sulphonate or sulphate is soluble and the other of which is an aqueous solution of an inorganic salt other than the neutralizing agent, turbulently mixing the acid sulphonation products with the said vehicle and thereafter separating the two liquid phases, e.g. by decantation or centrifugal action.  The organic layer contains neutralized sulphonate substantially free from inorganic salts.  It may be evaporated down to recover the pure sulphonates; a portion of the aqueous layer may be evaporated therewith when an admixture of sulphonate and inorganic salt is desired.  The usual detergent additives may be added to the organic layer.  The method may be applied to neutralization of sulphonated mono- and di-glycerides of higher fatty acids, e.g. lauryl mono-glyceride sulphate, sulphated higher fatty alcohols, higher fatty acid esters of low molecular weight alkylol sulphonic acids, e.g. the oleic ester of isethionic acid, higher fatty alcohol esters of sulpho-carboxylic acids, e.g. dioctyl sulpho - succinate, hydroxysulphonated fatty acid esters, e.g. lauryl ester of 2 : 3-dihydroxy propane sulphonic acid, alkylated aryl sulphonates, e.g. dodecyl benzene sulphonate and butyl naphthalene sulphonate, sulphonated mineral oil extracts, sulphonated fatty acids or glycerides and mahogany sulphonates. The preferred organic solvents are methanol, ethanol, propanols and butanols. Specified neutralizing agents are alkali metal, ammonium and calcium hydroxides, carbonates and/or bicarbonates. The inorganic salts used in the aqueous phase of the neutralizing vehicle are preferably sulphates or chlorides.  The cation of the salt may be the same as or capable of displacing the cation of the neutralizing agent.  The concentration of the inorganic salt is preferably such that the aqueous phase is saturated at least by the end of the neutralization. In typical examples: (2) the acid product obtained by sulphating coconut oil mono-glyceride is slowly run into a stirred two-phase vehicle of ethanol and a slurry of sodium carbonate and aqueous sodium sulphate, whereafter the upper layer of sulphonate is adjusted to pH 5.8-6.2 and evaporated down or the solids content adjusted to 20 per cent to form a shampoo; (6) the acid product obtained by sulphating dodecyl alcohol is neutralized as in (1); (7) the acid sulphonation product of (1) is run into a stirred slurry of calcium hydroxide and sodium bicarbonate in a two liquid phase vehicle of ethanol and aqueous sodium bicarbonate and thereafter the upper layer of sodium sulphonate is separated from the aqueous layer of sodium and calcium sulphates; (8) the acid product obtained by sulphonation of C12 alkylated benzene is neutralized as above with a slurry of soda ash in a two liquid phase vehicle of isopropanol and aqueous sodium sulphate. Specification 666,206 is referred to.