Sulfopropylated hemicellulose: Synthesis and NMR characterization

Sulfopropylation of hemicelluloses was achieved in dimethyl sulfoxide solution. The progress of sulfopropylation reaction was studied as a function of the dimsyl/hemicellulose ratio, reaction time with dimsyl (dimethylsulfinyl carbanion), propanesultone/hemicellulose ratio, and reaction time with propanesultone. The degree of substitution of sulfopropylhemicelluloses ranged between 0,5 and 1,1 as a function of experimental conditions. Intrinsic viscosity (0,1—0,3 dl/g) and molecular weight measurements (15000 g.mol—1) showed a controllable degradation of hemicellulose chains during the reaction. The NMR characterization of enzymatically degradated sulfopropylhemicelluloses indicated a homogeneous substitution along the polysaccharide chains. A significant regioselectivity for the OH-2 hydroxyl groups was observed only for DS ≤ 0,5.