Synthesis and characterization of aminocellulose sulfates as novel ampholytic polymers

Amino cellulose sulfate (ACS); namely 6-deoxy-6-(omega-aminoethyl) amino cellulose-2,3(6)-O-sulfate (AECS) and 6-deoxy-6-(2-(bis-N',N'-(2-aminoethyl)aminoethyl)) amino cellulose-2,3(6)-O-sulfate (BAECS) were prepared by a three step synthesis starting with the functionalization of microcrystalline cellulose with p-toluenesulfonyl (tosyl) groups (degree of substitution, DSTos between 0.55 and 1.37). Subsequently the introduction of the sulfate moieties was carried out (DSSulf between 1.09 and 1.27) and the tosyl groups at position 6 were replaced by a nucleophilic substitution reaction. As nucleophilic agents 1,2-diaminoethane and tris-(2-aminoethyl)amine were applied, yielding AECS (DSAEA values between 0.41 and 0.86) and BAECS (DSBAEA values between 0.32 and 0.74), respectively. The ACS samples were characterized by means of elemental analysis, C-13-NMR-, FT-IR-, and UV-Vis spectroscopy. Moreover, the solubility of the samples in water at different pH values and the molecular weights of the samples in aqueous solution were studied.