【摘要】 本文用模型小分子一缩二乙二醇的醚键断裂实验证明了可行性,羟乙基瓜尔胶上的羟乙基链段与过量对甲苯磺酸-乙酸酐在130℃下反应14hr,醚键完全断裂生成酯,并在pH=11条件下煮沸1hr使酯完全水解,转变为乙二醇。通过1H-NMR定量乙二醇,即可准确得到羟乙基瓜尔胶的羟乙基摩尔取代度。更多还原

【Abstract】 An improved chemical method for the determination of the molar substitution degree of hydroxyethyl guar gum has been described.The hydroxyethyl groups were totally cleaved from modified galactomannans at 130℃ in the presence of excess mixed p-toluenesulfonic-acetic anhydride for 14 hours,and then the products entirely hydrolyzed into ethylene glycol at pH=11 for an hour.Quantifying the mass of reaction products derived from the hydroxyethyl group,the molar substitution degree of the low-substituted hydroxyethyl guar gum can be exactly estimated.更多还原