【作者】 邵妙娟；

【导师】 杨亦文； 魏作君；

【作者基本信息】 浙江大学 ， 应用化学， 2007， 硕士

【摘要】 采用不同催化剂转酯化法从羊毛脂中获得游离胆固醇,分别研究了以甲醇钠、甲酸及强碱阴离子树脂为催化剂的工艺方法。以甲醇钠为催化剂,以甲醇为反应溶剂的转酯化工艺,考察了胆固醇的稳定性,原料含水量、甲醇用量、甲醇钠用量、反应温度和时间等因素的影响。确定最佳反应条件为:甲醇用量为原料(羊毛脂)的1倍(V/Wt),甲醇钠用量为总胆固醇质量的6.4%,反应温度60℃。在该工艺条件下反应1h,胆固醇产率为99%。在甲醇和乙醇两个近临界醇体系中以甲酸催化羊毛脂转酯化反应。在这两个体系中,含水量对产率均有显著影响。当溶剂初始pH值保持在2.5～3.5时,甲酸用量的改变对产率的影响不大。在140～200℃范围内,产率随着反应温度的升高而增加。在90%乙醇体系中,反应时间从4 h变化至8 h,产率没有增加。而在无水甲醇体系(200℃)产率随着反应时间有明显增加。得到最优条件为:无水甲醇体系,pH=3.0,甲醇/羊毛脂(V/Wt)为10/1,反应温度为200℃,12h,产率为81.7%。以强碱阴离子交换树脂催化羊毛脂转酯化反应制取胆固醇的工艺过程选择强碱5#(大孔吸附型)和强碱3#(凝胶型)两种树脂作为催化剂。首先考察了树脂在反应温度下对胆固醇的静态吸附情况,实验结果表明两种树脂对胆固醇均无吸附。在釜式反应研究结果的基础上,着重研究了影响固定床转酯化反应的各个因素如进料流量、溶剂种类及配比、反应温度、接触时间对反应的影响。羊毛脂固定床转酯化反应制取胆固醇的最佳工艺条件为:以强碱3#树脂为催化剂,反应温度60℃,羊毛脂(Wt)/甲醇(V)/石油醚(V)比例为1/2/1,流速1.5 ml/min,胆固醇产率可达63.1%。更多还原

【Abstract】 In this paper, preparation of cholesterol by transesterificatiom of lanolin with different catalysts, i.e., sodium methoxide, formic acid, and two kinds of basic anion exchange resin, was investigated.First of all, the lanolin was transesterificated to yield cholesterol, with methanol as reaction solvent and sodium methoxide as catalyst. The stability of cholesterol during the reaction, the influencing factors such as the water content in raw lanolin, the ratios of methanol and sodium methoxide to raw material, the reaction temperature and time were considered. Results showed that the optimal reaction conditions were: 1:1 of methanol to raw lanolin, 6.4% of sodium methoxide to total cholesterol, reaction temperature 60°C and reaction time 1 h. Under such operation conditions, the yield of cholesterol reached 99%.Then, the paper studied the transesterification process of lanolin with formic acid as catalyst in subcritical alcohol (methanol and ethanol). We studied the stability of cholesterol. It is stable between 150°C and 215°C in the solution of methanol or ethanol. The process of transesterification was affected by water content, type of alcohol, reaction temperature, reaction time, and amount of catalyst. The optimal conditions were: pH 2.5～3.5, methanol/lanolin (v/wt) of 10/1, temperature 200°C, time 8 h. The yield of cholesterol reached 81.7%.Finally, the preparation of cholesterol by transesterification of lanolin with methanol over basic anion exchange resin was investigated. The catalysts were 5# strong basic resin (macroporous resin) and 3# strong basic resin (gel resin). The static adsorption of cholesterol on two resins at reaction temperature were studied. The results showed that two resins did not adsorb cholesterol. The influencing factors to transesterification in fixed bed were focused on feed flow rate, type and ratio of solvent, reaction temperature and contact time. The suitable conditions were as follows: 3# strong basic resin as catalyst, reaction temperature 60℃, the ratio of lanolin (wt) / methanol (v) / petroleum ether (v) 1/2/1, flow rate 1.5 ml/min, the cholesterol yield up to 63.1%.更多还原