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化学学报
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化学学报 ›› 2009, Vol. 67 ›› Issue (12): 1383-1388. 上一篇    下一篇

研究论文

2,2,6,6-四甲基哌啶氧化物自由基选择性氧化反应用于羟丙基化半乳甘露聚糖C-6位取代度的表征研究

丁 彬a 叶应庆a 尹 强a 崔俊杰b
王 克a 罗健辉c 江 波*,a

  

  1. (a四川大学绿色化学与技术教育部重点实验室 四川大学化学学院 成都 610064)
    (b京昆油田化学科技开发公司 江苏 昆山 215300)
    (c中国石油勘探开发研究院 北京 100083)

  • 投稿日期:2008-09-28 修回日期:2008-11-14 发布日期:2009-06-28
  • 通讯作者: 江波

Determination of the Degree of Substitution at C-6 by 2,2,6,6- Tetramethyl-1-piperidinyloxy Radical-mediated Selective Oxidation of Substituted Galactomannan

Ding, Bin a Ye, Yingqing a Yin, Qiang a Cui, Junjie b Wang, Ke a Luo, Jianhui c Jiang Bo *,a   

  1. (a Education Ministry, Key Laboratory of Green Chemistry & Technology of Sichuan University, Chengdu 610064)
    (b Jingkun Oil Field of Petrochina Ltd, Kunshan 215300)
    (c Research Institute of Petroleum Exploration and Development of Petrochina Ltd, Beijing 100083)
  • Received:2008-09-28 Revised:2008-11-14 Published:2009-06-28
  • Contact: Jiang Bo

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被引次数

2 | 1

TEMPO (2,2,6,6-四甲基哌啶氧化物自由基)-NaClO-NaBr是一种对伯羟基具有很高选择性的氧化反应体系, 系统研究了该体系对半乳甘露聚糖及其衍生物的氧化反应过程, 通过对氧化反应中NaOH消耗量的适时跟踪测定, 确定了氧化反应进程以及氧化反应终点, 利用FTIR和13C NMR对氧化产物的结构进行了表征, 进一步确证了TEMPO氧化体系可高选择性地将C-6位伯羟基完全氧化为羧酸. 首次将TEMPO氧化法用于羟丙基化半乳甘露聚糖C-6位取代度的测定, 利用氧化反应NaOH的消耗量计算出不同摩尔取代度的羟丙基半乳甘露聚糖C-6位伯羟基的取代度. 以此为依据, 对半乳甘露聚糖的羟丙基化反应机理进行了初步探讨, 从实验上进一步验证了半乳甘露聚糖羟丙基取代反应优先发生在C-6位伯羟基上.

关键词: 半乳甘露聚糖, 取代度, 羟丙基化, TEMPO, 选择性氧化

TEMPO (2,2,6,6-Tetramethyl-1-piperidinyloxy radical)-mediated oxidation of primary alcohol groups of galactomannan was studied at pH 10.2 and temperature of 0 ℃ with NaOCl as the primary oxidant. The high selectivity of reaction could be proved by using the FTIR and 13C NMR spectra and the end-point of oxidation process could be determined by the NaOH consumption. The oxidation process was investigated for a series of hydroxypropyl galactomannan with different molar degrees of substitution. It was shown that this oxidation could be used for the determination of the degree of substitution at C-6 position of the substituted galactomannan by comparing the difference of oxidation yields between substituted and natural samples. The formula for determination of the degree of substitution at C-6 position was established according to the consumption of NaOH during the oxidation process. Moreover, the hydroxypropyl reaction mechanism of galactomannan was investigated on the basis of determination of the degree of substitution at C-6 position.

Key words: galactomannan, degree of substitution, hydroxypropyl, TEMPO, selective oxidation