GB405398A - Improvements in the refining of cotton seed oil - Google Patents

Abstract

Cottonseed oil is freed from mucilaginous, resinous, and colour-forming substances by heating with an anhydrous solid boric ester of an aliphatic polyhydric alcohol, and mechanically separating the precipitated impurities. 0.5--5.0 per cent of the esters of glycerine or glycol, treatment at 160--180 DEG C. under reduced pressure, e.g. 15--50 mm. of mercury, and centrifuging are suitable. The oil may first be partially freed from mucilaginous substances, as by emulsifying with water or dilute solutions of phosphoric acid, sodium chloride, or other electrolytes, and partially bleached by known methods. It may subsequently be heated with caustic potash or soda; deacidification as by distillation under reduced pressure, preferably with wet or dry steam or mists or vapours of inert liquids, e.g. as described in Specifications 213,267 and 313,254, [both in Class 91, Oils &c.], may follow or accompany the treatment with esters. For example, 100 lb. of crude cotton oil is mixed with 1 lb. of ester obtained by heating to 150 DEG C. for 3 hours, 14 parts by weight of anhydrous boric acid with 13 parts of 94 per cent glycerine; the mixture is subjected at 245 DEG C. and 20 mm. pressure to the deacidification process described in Specification 213,267; after filtration the oil is treated with 5 per cent caustic soda solution and with 3 per cent of a bleaching earth. Specification 341,390 also is referred to.ALSO:Anhydrous esters of boric acid are obtained by heating anhydrous boric acid with commercial glycerine to 150 DEG C. for 3 hours. The esters may be ground in a ball mill to fine dust. Boric acid esters of other aliphatic polyhydric alcohols, e.g. ethylene glycol, in which the hydroxyl groups are wholly or partly esterified, may be similarly prepared.