回流操作条件下植物甾醇与过量乙酸酯化反应动力学  

Study on the Esterification Kinetics of Phytosterols with Excess Acetic Acid under Reflux Conditions

作　　者：许文林[1] 黄一波[1] 沙鸥[1] 王雅琼[1] 张小兴[1] 

机构地区：[1]扬州大学化学化工学院,江苏扬州225002

出　　处：《高校化学工程学报》2005年第3期379-383,共5页Journal of Chemical Engineering of Chinese Universities

基　　金：国家自然科学基金(20176047);江苏省教育厅自然科学基金资助项目(99kjb150007);江苏高校高新技术产业发展面上项目(JHB04-033)

摘　　要：以豆甾醇、β-谷甾醇、菜油甾醇和菜籽甾醇与乙酸的酯化反应为研究体系,测定了回流操作条件下甾醇与过量乙酸的酯化反应动力学,研究了强酸性苯乙烯型阳离子交换树脂作为催化剂对酯化反应速率的影响以及系统中水的含量对反应速率和酯化反应转化率的影响.实验结果表明,豆甾醇、β-谷甾醇、菜油甾醇和菜籽甾醇与乙酸在回流条件下反应动力学方程均为: r =(0.278±0.002)×CSL·mol·L-1·h-1),加入0.5%～5.0%的催化剂量对反应速率常数的影响在5%以内,乙酸中含3.0%～15.0%的水时,反应转化率明显降低.此外还对精制混合甾醇与乙酸反应分离制备甾醇乙酸酯的工艺进行了研究以及对甾醇乙酸酯产物的热力学性质进行了分析测定,为应用化学反应和结晶法结合分离精制单组分植物甾醇提供了一定的理论依据和基础数据.Esterification kinetics of stigmasterol, β-sitosterol, brassicasterol and campesterol in excess acetic acid solution were determined under reflux condition. The effects of strongly acidic styrene cation exchange resin as catalyst and the content of water in the acetic acid on the reaction kinetics and esterification results were also studied. The experimental results show that rate equation of esterification for each kind of four sterols with acetic acid under reflux condition is nearly the same and could be expressed as r=(0.278±0.002) × CSL (mol&middotL-1&middoth-1. When the amount of catalyst added varies in the range of 0.5%-5.0% (by mass), the influence of its amount used on the rate constant is below 5%, and when content of water in the acetic acid varies from 3.0% to 15.0% (by volume), the esterification conversion decreases greatly. In addition, the melting points and the solubilities of esterified products in different kinds of organic solvents were also determined. The experimental results provide a theoretic base for separating and purifying phytosterols by using a combining chemical reaction and crystallization method.

关 键 词：植物甾醇 酯化反应 动力学 乙酸 

分 类 号：TQ654.98[化学工程—精细化工]