GB636295A - Improvements in and relating to the production of water-soluble mixed cellulose ethers - Google Patents

Abstract

A water-soluble mixed ether of cellulose containing the cyano-ethyl group is obtained by dissolving a water-insoluble alkali-soluble cellulose ether, the degree of substitution of which does not exceed one ether group per anhydroglucose unit of the cellulose, in a dilute aqueous alkali hydroxide solution containing not more than 6 per cent by weight of caustic alkali, and reacting on the solution obtained with from 0.1 to 2.5 mols. of acrylonitrile per anhydroglucose unit originally present in the cellulose. The water-insoluble cellulose ether may be a lowly substituted methyl or hydroxyethyl cellulose ether. The acrylonitrile may be added in drops to the solution of cellulose ether while stirring or shaking, the temperature of the reaction being maintained at 20 DEG C. The water-soluble mixed ethers may be obtained from the reaction mixture by stirring the mixture into a weak aqueous solution of hydrochloric acid to obtain a clear, slightly acid, solution which can then be purified by dialysis in a regenerated cellulose casing. If the mixed ether is required as a paste, the dialyzed solution may be concentrated by evaporation under reduced pressure. If the solid ether is required, the dialyzed liquid may be concentrated by vacuum distillation and the ether is precipitated by adding alcohol or acetone. The mixed ether may be obtained by directly precipitating from the neutralized reaction mixture by the addition of alcohol or acetone. The mixed ethers are readily soluble in acidic, neutral, or alkaline aqueous solutions as well as in hot or cold water. They may be used as sizes for textile yarns, particularly for viscose rayon warp yarns. They may be used as emulsifying agents, thickeners for printing pastes, and adhesives for wall-papers. They are resistant to attack by micro-organisms. In an example, a mixed ether containing 0.36 cyano-ethyl groups per anhydroglucose unit is obtained by the action of acrylonitrile on a solution in 4 per cent caustic soda of a water-insoluble hydroxyethyl cellulose. In another example, a mixed ether containing 0.4 cyanoethyl groups per anhydroglucose unit is obtained by the action of acrylonitrile on a solution in 5 per cent caustic soda of a water-insoluble methyl cellulose. Specifications 344,488, 374,964, 588,751 and 592,352, are referred to.