羟丙基瓜尔胶合成工艺的研究

SYNTHETIC PROCESS STUDY OF HYDROXYPROPYL GUAR GUM

研制出一步溶媒法工艺合成羟丙基瓜尔胶，使改性反应针对胚乳片进行，直接加工得到羟丙基瓜尔胶。研究了合成过程中乙醇溶液、氢氧化钠、环氧丙烷、反应温度、反应对阊等因素对产品表观黏度和水不溶物含量的影响。确定的合成工艺的技术条件为乙醇溶液质量分数为75％，氢氧化钠、环氧丙烷与胚乳片质量比分别为0．4：1和0．9：1，反应温度80～85℃，反应时间240～270min。合成的羟丙基瓜尔胶，水不溶物为1％～3％，表观黏度为130～140mPa·s，在表观黏度与瓜尔胶原粉保持一致的情况下，水不溶物大幅下降88％，水溶性得到明显改善。

One-step solvent media process to produce hydroxypropyl guar gum （HPG）is developed, endosperm splits are modified and directly pulverized into HPG powder. The influences of the factors, such as ethanol solution, sodium hydroxide, propylene oxide, reaction, temperature, reaction time on apparent viscosity and water insoluble substance of HPG are studied. The synthetic process technology fators are provided as follows： the mass fraction of ethanol solution is 75 %, the mass ratio of sodium hydroxide to endosperm splits is 0,4 ： 1, the mass ratio of propylene oxide to endosperm splits is 0.9 ： 1, reaction temperature is 80- 85℃, reaction time is 240- 270min. Water insoluble substance and apparent viscosity of HPG are 1% - 3 % and 130 - 140 mPa·s, respectively. On the occasion of the apparent viscosity of HPG is similar to that of guar gum （GG）, water insoluble substance is decreased by 88 %, solubility is greatly improved.