Koschella, A; Leermann, T; Brackhagen, M; Heinze, T
Sulfonic acid esters of differently linked polysaccharides including cellulose, dextran, lichenan, and pullulan were synthesized homogeneously applying N,N-dimethylacetamide/LiCl as the solvent. The dependence of the degree of substitution (DS) on the molar ratio of repeating unit to sulfonic acid chloride and on the structure of the reagent (benzene-, p-toluene-, 4-chlorobenzene-, 2,4-dinitrobenzene-, 2,4,6-trimethylbenzene-, and 2,4,6-triisopropylbenzene sulfonic acid chloride), as well as on the polysaccharide, was studied. DS values in the range of 0.2-2.3 were obtained. Bulky and electron withdrawing substituents on the aromatic ring inhibited ester formation. None of the sulfonic acid chlorides applied showed distinct regioselectivity. The polysaccharide sulfonic acid esters were soluble in organic solvents depending on the type of substituent and the degree of substitution. The molecular Structure of the new polymers was confirmed by elemental analysis, FTIR, and C-13-NMR spectroscopy. Subsequently, nucleophilic displacement reactions were carried out, which showed that the reactivity of the primary sulfonic acid ester group was higher than that of the secondary ones. (c) 2006 Wiley Periodicals, Inc.