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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13CNMR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.
TEMPO (2,2,6,6-tetramethylpiperidine oxide free radical) -NaClO-NaBr is a highly selective primary oxidation of the oxidation reaction system, the system of galactomannan poly Sugar and its derivatives oxidation process, through the oxidation of NaOH consumption in the timely follow-up determination to determine the oxidation reaction process and the end of the oxidation reaction, the use of FTIR and 13CNMR structure of the oxidation products were characterized to further confirm the TEMPO Oxidation system can be highly selective C-6 primary hydroxyl oxidation to carboxylic acid.For the first time the TEMPO oxidation method for hydroxypropylated galactomannan C-6 degree of substitution determination, the use of oxidation of NaOH The degree of substitution of C-6 primary hydroxyl groups of hydroxypropyl galactomannan with different molar substitution was calculated.On the basis of this, the hydroxypropylation reaction mechanism of galactomannan was preliminarily discussed, It was further verified experimentally that galactomannan hydroxypropyl substitution preferentially occurs at the C-6 primary hydroxyl group.