TEMPO-mediated oxidation of chitin, regenerated chitin and N-acetylated chitosan
TEMPO-mediated oxidation of chitin, regenerated chitin and N-acetylated chitosan
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DOI：
10.1016/j.carbpol.2004.08.011
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发表时间：
2004-12-07
影响因子：
11.2
通讯作者：
Isogai, A
中科院分区：
文献类型：
--
作者：
Kato, Y;Kaminaga, J;Isogai, A
以市售甲壳素为原料，用6.8%NaOH溶液和N-乙酰化壳聚糖(DNAc)制备再生甲壳素，在水中用NaClO和2，2，6，6-四甲基哌啶氧自由基(TEMPO)和NaBr催化氧化。以DNAc为87%的再生甲壳素和DNAc为93%的N-乙酰化壳聚糖为原料，在70min内定量得到聚合度约为300的水溶性β-1，4-交联型聚N-乙酰氨基葡萄糖(壳质酸)钠盐。而原甲壳素和N-乙酰化壳聚糖的DNAc为77%，由于氧化不完全，未得到水溶性产物。原始甲壳素结晶度较高，反应活性较低，DNAc含量为77%的N-乙酰化壳聚糖的C2-氨基含量较高，导致降解，而不是C6羟基的选择性氧化。制得的壳质酸在水中粘度低，可被土壤微生物降解。(C)2004爱思唯尔有限公司。保留所有权利。
A commercial chitin, regenerated chitin prepared from chitin solutions in 6.8% NaOH and N-acetylated chitosans with degrees of N-acetylation (DNAc) of 77-93% were subjected to oxidization in water with NaClO and catalytic amounts of 2,2,6,6-tetramethylpiperidinyloxy radical (TEMPO) and NaBr. When regenerated chitin with DNAc of 87% and N-acetylated chitosan with DNAc of 93% were used as starting materials, water-soluble beta-1,4-linked poly-N-acetylglucosaminuronic acid (chitouronic acid) Na salts with degrees of polymerization of ca. 300 were obtained quantitatively within 70 min. On the other hand, the original chitin and N-acetylated chitosan with DNAc of 77% did not give water-soluble products, owing to incomplete oxidation. The high crystallinity of the original chitin brought about low reactivity, and the high C2-amino group content of the N-acetylated chitosan with DNAc of 77% led to degradations rather than the selective oxidation at the C6 hydroxyls. The obtained chitouronic acid had low viscosities in water, and clear biodegradability by soil microorganisms. (C) 2004 Elsevier Ltd. All rights reserved.