GB318908A - Process for the manufacture of chloracetic cellulose esters - Google Patents

Abstract

318,908. Soc. des Usines Chimiques Rh¶ne-Poulenc, (formerly Soc. Chimique des Usines du Rhone). Gault, H., and Bidaud, F. June 12, 1928. Right to Patent relinquished. Cellulose carboxylates. - Cellulose esters of monochloracotic acid are prepared by heating cellulose or its near conversion products, such as oxyeellulose or hydrocellulose, with monochloracetic anhydride in the presence of a catalyst such as sulphuric acid, methane sulphonic acid, or zinc chloride. Cellulose chloracetate can be separated from the more or less viscous solutions obtained by precipitation with ether or alternatively a product containing a lower percentage of fixed chlorine and less soluble in organic solvents can be obtained by diluting the reacting mass with ether before the cellulosic fibre has dissolved. The esterification may be effected in presence of a diluent, for example, monochloracetic acid. In one example, cotton or wood pulp is heated at 55-60‹ C. with monochloracetic anhydride. A melted mixture of monochloracetic anhydride and sulphuric acid is then added and after the mass has disintegrated, the mixture is further heated at 60‹ C. to give a viscous solution from which cellulose monochloracetate containing 22.5 per cent of chlorine is precipitated. for example by ether or alcohol. By evaporation of the ether or alcohol, the excess of these reagents can be recovered. In another example, the procedure is the same except that zinc chloride is employed as catalyst and the heating is conducted at 80‹. Transparent films can be obtained by evaporation of solutions of cellulose monochloracetate.