GB683069A - Improvements in and relating to the production of water-soluble mixed cellulose ethers - Google Patents

Abstract

Water-soluble mixed cellulose ethers containing cyanoethyl groups and alkyl groups are produced by dissolving a water-insoluble, alkali-soluble cyanoethyl ether of celluose having 0.01 to 0.5 cyanoethyl group per anhydroglucose unit of the cellulose in a dilute aqueous solution containing 3-6 mols. of an alkali metal hydroxide or 1-2 mols. of a quaternary ammonium hydroxide per anhydroglucose unit of the cellulose and reacting the solution obtained with 0.3-3 mols. of an alkylating agent per anhydroglucose unit originally present in the cellulose of the water-insoluble, alkali-soluble cyanoethyl ether of cellulose, the alkylating agent containing one or more alkyl groups each having not more than four carbon atoms. The alkylating agent is preferably a dialkyl sulphate, e.g. dimethyl, diethyl or methylethyl sulphate or a mixture of dimethyl and diethyl sulphates. Alkyl halides such as ethyl chloride may be used as alkylating agents. The alkylation is preferably carried out at 15-30 DEG C. In an example, 1 kg. of a water-insoluble, alkali-soluble cyanoethyl ether of cellulose containing 0.26 cyanoethyl group per anhydroglucose unit of the cellulose prepared in a described manner is soaked in 10 litres of water, 4 litres of water containing 0.75 kilogram of sodium hydroxide is added and the mixture diluted with water to 20 litres. 576 mils. of dimethyl sulphate are added and mixture stirred for 4 hours at 25 DEG C. The mixture is neutralized with a 15 per cent aqueous solution of hydrochloric acid and dialized in a regenerated cellulose casing by means of a continuous stream of softened water until free from electrolytes. The solution is then concentrated to a paste by distillation under reduced pressure and the mixed ether precipitated by the addition of ethyl alcohol, filtered, washed with alcohol and air dried. Examples are given of the preparation of cellulose ethers by similar methods using aqueous solutions of dimethyldibenzyl - ammonium hydroxide in place of sodium hydroxide and also an example in which ethyl chloride is used as the alkylating agent in conjunction with sodium hydroxide in an autoclave. The compositions of the products obtained in the examples are given. Aqueous solutions of the mixed ethers are stable on long standing and not gelatinized by heating. They are compatible with aqueous solutions of anionic and cationic surface-active substances and with non-ionic detergents. Aqueous solutions of the mixed ethers may be used as sizes for textile yarns. Specifications 588,751 and 636,295 are referred to.