N-Alkylations of chitosan promoted with sodium hydrogen carbonate under aqueous conditions

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• 作者：Y. Kurita ; A. Isogai ; ^{aisogai@mail.ecc.u-tokyo.ac.jp}
• 关键词：Chitosan ; N-Alkylation ; N-Carboxymethyl chitosan ; N ; N-Dicarboxymethyl chitosan ; N-Benzyl chitosan ; SEC-MALLS
• 刊名：International Journal of Biological Macromolecules
• 出版年：2012
• 期刊代码：62_01418130
• 类别：abs
• 出版时间：1 April, 2012
• 卷：50
• 期：3
• 页码：741-746
• 文件大小：1427 K

摘要

Chitosan was reacted with four alkyl halides, monobromoacetic acid, benzyl bromide, 2-bromoethanol, and monochloroacetic acid, in the presence of NaHCO₃ in water. Chemical structures, degrees of substitution, and degrees of polymerization of reaction products were studied by FT-IR, NMR, SEC-MALLS, and elementary analyses. All alkyl groups were introduced selectively into the C2-amine groups of chitosan, and the yields of the N-alkyl chitosans were >90%by this method. N-Carboxymethyl chitosan (N-CMCh) and N-benzyl chitosan (N-BnCh) with high degrees of substitution (DS) up to 200%and 164%of the C2-amine groups, respectively, were obtained; N,N-dicarboxymethyl and N,N-dibenzyl chitosans were obtained in high yields. Degrees of polymerization (DP) of N-CMCh decreased during the reaction. The greater the amount of monobromoacetic acid added, the lower the DP of N-CMCh.