Abstract-A new procedure was developed for preparation of chelate amino-containing polymer N-2-sulfoethyl chitosan by synthesis in a gel through the reaction between chitosan and sodium 2-bromoethanesulfonate, yielding a polymer with the degree of substitution of up to 0.5. The structure of the resulting polymers was confi rmed by 1 H NMR spectroscopy. The sorption characteristics with respect to transition and alkaline-earth metal ions were determined for the cross-linked polymers.
DOI: 10.1134/S1070427213020225Sulfoethylation of polymers represents a productive procedure for polymer-analogous transformations, since incorporation of a strong acid residue into the macromolecule substantially modifi es the properties of the initial polymer. For example, 2-sulfoetylation of synthetic polymers allows preparation of stationary phases for HPLC [1,2], ion-conducting membranes [3], catalysts [4,5], and antimicrobial agents [6]. In the case of natural polymers, modifi cation with 2-sulfoethyl groups has gained wider acceptance as a method of preparation of products suitable for manufacture of membranes intended for various applications [7,8], biopolymeric surfactants [9,10], and 3d-metal ion sorbents [11,12]. Modifi cation signifi cantly affects the bioactive properties of the initial polymer matrices; the modifi ed polymers exhibit antimutagenic [13][14][15][16] Chitosan is a linear amino polysaccharide whose structure is nearly identical to that of cellulose, except for the fact that the pyranose ring bears an amino, instead of a hydroxy, group on the C-2 position, whereby it acquires high complexing power with respect to metal ions. The presence of highly reactive amino and hydroxy groups in chitosan allows for easy modifi cation and extends the application range of the polymer.Sulfoethylation of chitosan and carboxymethylated chitosan with sodium 2-chloroethanesulfonate [18,19] and sodium vinyl sulfonate [12] in a strongly alkaline medium leads to nonselective N,O-substituted product.Here, we developed a procedure for synthesis of N-2-sulfoethyl chitosan (SEC), a promising derivative of the amino-containing polymer of natural origin, and examined its sorption properties with respect to transition and alkaline-earth metal ions.
EXPERIMENTALWe used chitosan available from Sonat (degree of deacetylation 0.84, molecular weight 250 kDa, ash residue 0.19%). The degree of deacetylation was determined by 1 H NMR spectroscopy, and the molecular weight, viscometrically [20]; sodium 2-bromoethanesulfonate was available from Alfa Aesar and used without further purifi cation.For C,H,N analysis served a Perkin Elmer automatic analyzer. The diffuse refl ection IR spectra were measured
