A new water-soluble derivative of chitosan chitosan oligoethylene oxide sulfonate was synthesized. The ratio and concentration of reacting substances and temperature and duration of the chitosan modification reaction affect the composition and properties of the reaction products. The conditions that ensure a 100% yield of water-soluble chitosan derivatives were determined. Using potentiometric titration and IR spectroscopy, the formation of a new water-soluble chitosan derivative oligoethylene oxide sulfonate was confirmed.The interest of researchers in the study of polymer-analog transformations of chitosan and fabrication of new chitosan derivatives is due to both the unique properties of this polysaccharide and the broad possibilities of chemically modifying it by alkylation, acylation, salt formation, and complexation reactions. The specific features of the chemical structure of chitosan create grounds for fabrication of water-soluble film-and fibre-forming derivatives of different types whose properties are determined by the structure of the added substituents to a significant degree [1][2][3][4][5].To obtain new water-soluble chitosan derivatives, we used reactive ethylene oxide oligomers containing a sulfo group. One of these compounds oligoethylene oxide sulfonate (OES) was fabricated from oligoethylene oxide sodium sulfonate (OES-Na) ( Table 1) by ion exchange.Ion exchange was conducted in dynamic conditions by passing aqueous solutions of OES-Na through a column packed with KU-2-8 cation exchanger. Conversion from the Na form to the H form was monitored by the content of sulfoxyl (SO 3 H) groups in sulfonic acid oligoester (SAOE) by titration with 0.1 N NaOH solution in the presence of methyl red indicator or by potentiometric titration on a pH-340 pH-meter. The error of measurement did not exceed 0.25% at the 0.95 confidence level.The concentration of the initial solution of the oligomer and the rate of its passage through the column significantly affects the completeness of conversion of the salt form of OES-Na into the sulfonic acid form of OES. We investigated the effect of the OES-Na content on the degree of substitution of Na + cation by H + (Table 2). We found that the optimum oligomer content in aqueous solution that guarantees quantitative conversion of the Na form into the H form was 3-6%. The rate of passage of the solution through the column should not exceed 2 ml/min. The sulfonic acid oligoester separated from the solution is a viscous, colorless, transparent substance readily soluble in water.Chitosan preparations with a molecular weight of 4.2⋅10 5 and 1.9⋅10 6 were used to prepare the derivatives containing OES-H residues ( Table 3).The reaction of the amino groups in the chitosan macromolecule with the OES sulfonate groups should primarily take place according to an ionic mechanism. The salts formed are actually a new derivative of chitosan oligoethylene oxide sulfonate (OSC), where the characterization of the composition and properties are of independent interest. OSC was synthesized ...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.