GB427388A - Carbohydrate derivatives and processes for making same - Google Patents

Abstract

Mixed ethers of carbohydrates are prepared by subjecting to alkylation or aralkylation an alkali-soluble oxyalkyl derivative of a carbohydrate, which has been prepared in the presence of alkali. The products may be soluble in water and in benzene. The parent material may be one in which not less than two and preferably not less than three molecules of oxyalkylating agent have been used in the oxyalkylation of one molecule of carbohydrate. The alkali-soluble oxyalkyl derivative may be alkylated in dilute solution, for instance in a solution containing not more than three per cent of the oxyalkyl derivative. Suitable processes for alkylation or aralkylation are those described in Specifications 12854/12, 6035/13, 149,318, 149,320, 163,018, 177,809, 181,393, 181,395, 200,815, [all in Class 2 (ii)], and 427,387. In an example, an 8 per cent solution of alkali-soluble ethylene (or propylene) glycol ether of cellulose, or glycerine ether of cellulose in caustic soda solution is etherified by means of di-ethyl sulphate. In other examples, a 3 per cent solution of propylene glycol ether of cellulose or glycerine ether of cellulose in caustic soda solution is etherified by means of di-ethyl sulphate; a 6 per cent solution of ethylene glycol ether, propylene glycol ether, or glycerine ether, of cellulose, in caustic soda is etherified by means of di-ethyl sulphate in two stages with the addition of caustic soda and di-ethyl sulphate between the stages; an alkali-soluble ethylene glycol ether, propylene glycol ether or glycerine ether of cellulose, is mixed with caustic soda solution and heated with ethyl chloride which may be diluted with benzene; an alkali-soluble ethylene or propylene glycol ether or glycerine ether of cellulose, is mixed with caustic soda solution, powdered caustic soda, and sodium carbonate, and etherified with ethyl chloride. Other examples are given in which the alkali-soluble parent material is prepared by the action of ethylene oxide on cellulose in the presence of caustic alkali. In other examples, starch or dextrin is reacted with ethylene chlorhydrin or a -monochlorhydrin in the presence of caustic soda and then etherified with ethyl chloride or di-ethyl sulphate. The products may conveniently be separated by acidification of the solutions in which they are obtained, followed by heating, or by acidification followed by dialysis, filtration, and precipitation by evaporation or addition of alcohol. Specifications 231,807, [Class 2 (ii)], and 427,386 also are referred to.