title: Imidazolyl derivative of chitosan with high substitution degree: Synthesis, characterization and sorption properties.
abstract: A method of synthesis of chitosan imidazolyl derivative - N-(5-methyl-4-imidazolyl)methylchitosan (IM-chitosan) with high degree of substitution (DS) via reaction with 5-methyl-4-imidazolylmethanol has been developed. This method enables one to obtain polymers with the DS up to 1.35 with simultaneous cross-linkage of the matrix. The chemical structure of the obtained IM-chitosan was characterized by FT-IR, (13)C and (15)N NMR spectroscopies. It was shown that cross-linkage of IM-chitosans occurred due to formation of N-glucoside derivatives. Sorption capacities of IM-chitosans toward transition metal ions have an extremal dependence on DS, which is less pronounced for Ag(I) ions in comparison with Cu(II) and Ni(II) ions. The decrease of sorption capacities for derivatives with DS 0.5-1.0 is attributed to steric hindrances for ion-binding due to increased stiffness of the polymer matrix at high DS as a result of cross-linking. Sorption capacities of IM-chitosans toward noble metal ions in 0.1M HCl gradually increase with DS, since higher swelling polymers in acidic media eliminates negative effect of cross-linking on availability of sorption sites.
authors.affiliation: I. Ya. Postovsky Institute of Organic Synthesis, Ural Branch of RAS, 22, S. Kovalevskoy str., Yekaterinburg 620137, Russia. Electronic address: pestov@ios.uran.ru.
authors.forename: Alexander V
authors.initials: AV
authors.lastname: Pestov
authors.affiliation: I. Ya. Postovsky Institute of Organic Synthesis, Ural Branch of RAS, 22, S. Kovalevskoy str., Yekaterinburg 620137, Russia.
authors.forename: Alexander V
authors.initials: AV
authors.lastname: Mehaev
authors.affiliation: I. Ya. Postovsky Institute of Organic Synthesis, Ural Branch of RAS, 22, S. Kovalevskoy str., Yekaterinburg 620137, Russia.
authors.forename: Mikhail I
authors.initials: MI
authors.lastname: Kodess
authors.affiliation: I. Ya. Postovsky Institute of Organic Synthesis, Ural Branch of RAS, 22, S. Kovalevskoy str., Yekaterinburg 620137, Russia.
authors.forename: Marina A
authors.initials: MA
authors.lastname: Ezhikova
authors.affiliation: Institute of Chemistry, Far East Branch of RAS, 159, prosp.100-letiya Vladivostoka, Vladivostok 690022, Russia.
authors.forename: Yulya A
authors.initials: YA
authors.lastname: Azarova
authors.affiliation: Institute of Chemistry, Far East Branch of RAS, 159, prosp.100-letiya Vladivostoka, Vladivostok 690022, Russia.
authors.forename: Svetlana Yu
authors.initials: SY
authors.lastname: Bratskaya
keywords: Chitosan; Imidazolylmethyl derivatives; Sorption