微波辅助半干法合成阳离子瓜尔胶工艺条件的优化

Optimization of process conditions for synthesis of cationic guar gum by microwave-assisted semi-dry method

以瓜尔胶为原料,2,3-环氧丙基三甲基氯化铵为醚化剂,氧氧化钠为催化剂,利用微波辅助半干法合成了阳离子瓜尔胶,并进行了红外和核磁表征。结果表明,在瓜尔胶醚化过程中使用微波辅助,反应时间是传统阳离子瓜尔胶合成方法的1/5,大大提高了反应效率。较佳反应条件为:微波功率640W,微波辐射反应时间45min,碱液与瓜尔胶的质量比为0.08∶1,微波温度60℃,在此条件下制备的阳离子瓜尔胶含氮量为1.23%。黏度实验表明:微波法合成的阳离子瓜尔胶水溶性好,黏度可达7000mpa·s。

Cationic guar gum(CGG) was synthesized with guar gum(GG) as raw materials,2,3-epoxypropyltrimethylammonium chloride(GTA) as cationic etherifying agent and sodium hydroxide as catalyst by microwave-assisted semi-dry method,and characterized by IR and NMR.The results show that microwaveassisted etherification of guar gum shortens the reaction time to 1/5 of that in the traditional cationic guar gum synthesis method,which greatly improves the reaction efficiency.The optimum synthesis conditions were as follows:microwave power 640 W,microwave irradiation reaction time 45 min,mass ratio of alkali liquor to guar gum 0.08∶1,microwave temperature 60 ℃.Under these optimized conditions,the nitrogen content of cationic guar gum is 1.23%.Viscosity experiment shows that the cationic guar gum synthesized by microwave-assisted semi-dry method has good water solubility and its viscosity can reach up to 7 000 mpa·s.