GB733947A - Manufacture of bis-(ª‰-hydroxyalkyl-) polysulphides - Google Patents

Abstract

Bis - (b - hydroxyalkyl) polysulphides are prepared by reacting a 1,2-alkylene oxide with an alkali-metal polysulphide or alkaline-earth metal polysulphide in an aqueous medium and neutralizing the base liberated in the reaction as it is formed in such a manner that the reaction mixture does not become acid. Thus stoichiometric amounts of 1,2-alkylene oxide and of an alkali-binding substance may be introduced simultaneously into an aqueous solution of the alkali metal or alkaline earth metal polysulphide. Specified alkali-binding agents are sodium bicarbonate, buffer solutions containing acetates, borates, phosphates and the like, mineral acids and, preferably, carbon dioxide. The preferred reaction temperatures are from about 30 DEG to 90 DEG C. The alkylene oxide, which include ethylene, propylene and 3-hydroxy-propylene 1 : 2 oxides, may be used in gaseous or liquid form. It is preferred to employ a mixture of sodium monosulphide and sulphur, rather than sodium polysulphide, the latter then forming in situ. In examples: (1) a mixture of carbon dioxide and ethylene oxide is passed into an aqueous solution of sodium sulphide and sulphur yielding bis-(hydroxyethyl) polysulphide of a sulphur content of 33 or 42.8 per cent depending on the sulphur content of the initial reaction mixture; (2) ethylene oxide is passed into an aqueous solution of sodium sulphide and sulphur while sulphuric acid is added dropwise with agitation; a bis-(hydroxyethyl) polysulphide is obtained and this product and the second product of (1) are catalytically hydrogenated to thioglycol.