Novel Cationic Esters Derived from Cellulose and Dextran

The synthesis of novel water-soluble cationic amino esters based on cellulose and dextran under homogeneous conditions is presented in this work. Products are synthesized via the ring-opening reaction of N-methyl-2-pyrrolidone in the presence of p-toluenesulfonyl chloride: cellulose-4-[N-methylammonium]butyrate chloride, hydroxyethyl cellulose-4-[N-methylammonium]butyrate chloride and dextran-4-[N-methylammonium]butyrate chloride. Cellulose-4-[N,N,N-trimethylammonium]butyrate chloride is obtained by conversion of cellulose with (3-carboxypropyl)trimethyl ammonium chloride activated with N,N'-carbonyldiimidazole. The products are characterized by elemental analysis, size-exclusion chromatography, FTIR- and NMR-spectroscopy. Polyelectrolyte titration is used to quantify the positive charges on the macromolecules in aqueous solutions at various pH values. Hydrolysis of the ester group is evidenced by potentiometric titration. Properties as viscosity of the products in aqueous solution and capability of polyelectrolyte complex formation are also investigated.