P-TOLUENESULFONYL ESTERS IN CELLULOSE MODIFICATIONS - ACYLATION OF REMAINING HYDROXYL-GROUPS

New soluble cellulosics with interesting molecular structures and prop erties were obtained by the acylation of remaining hydroxyl groups of pure, homogeneously synthesized p-toluenesulfonylcelluloses of differe nt degree of p-toluenesulfonyl (tosyl) substitution (DSTosyl) ranging from 0.5 to 2.0 in pyridine and sodium acetate as a catalyst with vari ous aliphatic, aromatic and unsaturated carbonic acid anhydrides as we ll as isocyanates. The reactions proceed homogeneously and yield produ cts of a high degree of acyl substitution (DSAcyl). In the case of ace tic and propionic acid anhydrides a complete functionalization of all free hydroxyl groups was achieved. Even with fatty acid anhydrides lik e stearic anhydride 94% of the remaining OH groups were acylated. The new polymers are readily soluble in common organic solvents such as ac etone, dimethyl sulfoxide, N,N-dimethylacetamide, N,N-dimethylformamid e, and tetrahydrofuran. They are solution processible film- and membra ne-forming materials. Tosylcellulose phthalates and trimellitates of a ppropriate DSTosyl and DSAcyl values are even soluble in aqueous NaOH. Compared to the original tosylcelluloses, the thermal degradation of tosylcellulose acylates was initiated at nearly the same temperature i ndependent of type and degree of esterification providing an equal DST osyl. The stability found is sufficiently high for processing.