Preparation of fibrous cellulose formate by the action of thionyl chloride in N, N-dimethylformamide

Abstract

Cotton cellulose yarn, either in the untreated state, or altered by swelling pretreatments involving mercerization or solvent-exchange, or both, reacts readily with solutions of thionyl chloride in N, N-dimethylformamide at room temperature. Subsequent hydrolysis produces cellulose formate as the major product; this derivative is presumably formed via reaction of the cellulose with the iminium salt, ▪ and a chlorodeoxycellulose. The reaction variables studied were the effect of ( a) preswelling the cellulose in N, N-dimethylformamide, ( b) the reaction time, ( c) the concentration of thionyl chloride, and ( d) the moisture content of the cotton prior to preswelling and reaction. The effect of various pretreatments on the type and rate of reaction which the cotton undergoes was also determined. The stability of the formyl group and of the sulfurous acid monoester group to hot water and to dilute ammonium hydroxide, as well as the tensile properties of yarns treated with thionyl chloride and N, N-dimethylformamide, were investigated.