植物甾醇结晶分离精制过程及酯化反应过程研究

【作者】 黄一波；

【导师】 许文林；

【作者基本信息】 扬州大学 ， 物理化学， 2004， 硕士

【摘要】 植物甾醇是一类非常重要的甾体化合物，主要来源于精炼植物油中的下脚料，特别是脱臭馏出物(又名DD油)中。植物甾醇在生物、医药和化妆品等领域有着极为广泛的应用价值。本文以单组分豆甾醇、β-谷甾醇和脱臭馏出物精制得到的混合植物甾醇为研究体系，应用溶剂结晶法分离精制单组分植物甾醇，应用反应与结晶法结合，研究植物甾醇的酯化反应过程，为实现该过程的工业化提供理论指导和技术参数。本研究主要在以下各方面开展工作： 1、溶剂结晶法分离精制植物甾醇： (1)植物甾醇在有机溶剂中的溶解特性及豆甾醇／β-谷甾醇／有机溶剂相图 测定了室温下植物甾醇在有机溶剂中的溶解度，环己酮、正丁醇和正戊醇等有机溶剂可以作为结晶分离植物甾醇的溶剂。测定了不同温度下豆甾醇和β-谷甾醇在正戊醇及环己酮中的溶解度。为了预测结晶实验中豆甾醇和β-谷甾醇的理论含量，测定了25℃和60℃下豆甾醇／β-谷甾醇／环己酮(正戊醇)三组分相图。实验结果表明：β-谷甾醇在环己酮和正戊醇溶剂中的溶解度比豆甾醇的大，且在环己酮中的溶解度随温度变化比豆甾醇大。 (2)重结晶与分步结晶法分离精制混合植物甾醇过程研究 以环己酮或正戊醇为溶剂，混合植物甾醇经过5次重结晶后，豆甾醇含量可达到92％；以环己酮为溶剂，混合植物甾醇经过三次分步结晶后，β-谷甾醇含量达到87％。研究了分离精制豆甾醇或β-谷甾醇的工艺条件，并用红外和紫外光谱法定量分析了提纯产物中豆甾醇和β-谷甾醇的含量。 2、植物甾醇的酯化反应过程研究： (1)植物甾醇与过量乙酸的反应 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扬州大学硕士学位论文速率和醋化反应结果的影响。并对混合植物幽醇与过量乙酸反应分离制备幽醇乙酸酷的工艺进行研究，对植物街醇乙酸酷产物的热力学性质进行分析测定。研究实验结果表明:豆昌醇、声谷多醇、菜油出醇和菜籽昌醇与过量乙酸在回流条件下反应动力学方程均为:厂(0 .278士0.ooZ)xc‘。(mol·L一’·h一’);加入2.5%一5.0%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%一巧.0%的水时，反应速率常数k从o.Z15h一‘下降到o.losh一’。(2)植物街醇与乙酸配的反应 研究了植物幽醇与乙酸配的反应，探讨了反应温度、反应时间、反应物的质量比对反应结果的影响，并用红外光谱和高效液相色谱对反应产物进行了表征。实验结果表明:90℃下，植物幽醇与乙酸配在质量比为1:10，反应时间为0.5h的反应条件下，转化率可达95.0%以上，植物幽醇乙酸醋的收率可达到92.0%以上。(3)植物出醇与唬拍酸配的反应 研究了介谷幽醇与墟拍酸醉的单酷化反应工艺。选择了甲苯作为溶剂，毗咙作为催化剂，在回流操作条件下的反应工艺和反应产物的分离精制工艺，并探讨了反应温度、反应时间以及催化剂的用量对醋化反应结果的影响。分别用FT一IR、HPLc、Dsc等方法对反应产物进行表征。实验结果表明:尽谷幽醇与玻拍酸配按摩尔比为1:1.6，加入1.5%的毗睫作为催化剂，回流下反应21h，反应物单醋化过程趋于完全，反应产物经处理后，尽谷街醇与玻拍酸醉反应的收率大于88%。 以尽谷出醇与唬泊酸醉的单酷化反应为研究体系，测定了甲苯作为溶剂下，毗咙作为催化剂，尽谷幽醇与唬拍酸配的酷化反应动力学。研究了催化剂浓度以及反应温度对速率常数的影响。依据不同温度下的反应速率常数，得出尽谷幽醇与琉拍酸配的单酷化反应的活化能和反应动力学方程。实验结果表明:以1.5%毗咙作为催化剂，60℃、80℃、110℃下，尽谷幽醇与唬泊酸配的单酷化反应速率常数为o.o4s5L·mol一l下’、o.1362L·mo一‘’·卜’和2.2467L·mol一’·h-l;得出反应的活化能为sl.4kJ·mol一‘，反应动力学方程为二dec/dt一2.72xlo‘’e一‘”‘RTe^eB。 本文的研究结果可以为混合植物幽醇的进一步分离和精制，提供理论指导和技术参数，也为植物出醇醋的工业化生产提供基础数据。本研究工作的创新之处黄一波:植物幽醇结晶分离精制过程及酷化反应过程研究在于利用不同幽醇在不同溶剂中的溶解性差异，应用溶剂结晶法实现复杂组分的精制和分离;首次提出反应、结晶分离相结合的研究思路，利用酷化反应增加植物街醇的物性差异;并对植物幽醇的醋化反应工艺及动力学过程进行研究。更多还原

【Abstract】 Phytosterol is ond kind of important steroids. It can be mainly obtained from waste oil of refining vegetable oil especially from deoderizer distillate (DD oil). Phytosterol is widely applied in the biochemical, pharmaceutics and cosmetic industry. The pure single phytosterol was purified and separated from phytosterol mixtures which were obtained from deoderizer distillate by the solvent crystallization method. The esterification process of stigmasterol, B-sitosterol and phytosterol mixtures were studied in order to separate and purify phytosterol mixtures by the combination of reaction and crystallization. The research results provide theorical basic and technological parameter for the industrialization of the process. The main research works were as follows:1. Purifying and separating phytosterols by crystallization method (1) The solubilities of phytosterols in organic solvents and the three-phase pharm of stigmasterol/B-sitosterol/solventThe solubilities of phytosterols in organic solvents were determined under room temperature. Cyclohexanone, n-butanol and n-pentanol all could be selected as solvents to purify and separate phytosterol mixtures by crystallization method. The solubilities of B-sitosterol and stigmasterol in cyclohexone or n-pentanol were determined respectively at different temperature further. The phase diagrams of stigmasterol /B-sitosterol/cyclohexanone (or n-pentanol) at 25C and 60C were determined in order to predict theoretical result in the experiment. The experimental results show that the solubility of B-sitosterol in cyclohexanone or n-pentanol is larger than that of stigmasterol in the same solvent at the same condition; the solubility of B-sitosterol increases much faster with temperature in cyclohexanone than that of stigmasterol.(2) The processes of purifying and separating phytosterol mixtures by recrystallization and fractional crystallization methodsThe content of stigmasterol is more than 92% after five stages crystallization in n-pentanol or cyclohexanone. And the content of B-sitosterol is more than 87% after the three fractional crystallizations in cyclohexanone. The processes of purifying stigmasterol and B-sitosterol were investigated, the content of stigmasterol and B-sitosterol were determined by FT-IR and Uv-vis spectroscopy analysis method. 2. The studies on the esterification process of phytosterol(1) The reaction between phytosterol and excess acetic acid solutionThe esterification kinetics of stigmasterol, B-sitosterol, brassicasterol and campesterol in excess acetic acid solution were determined under reflux condition. The effects of strongly acidic styrene cation exchangers as a catalyst and the content of water on the reaction kinetics and esterification results were also studied. In addition, the process of preparation for phytosterol acetate was discussed, and the thermodynamic properties of esterified products were also determined. The experimental results show that the rate equation of esterification for four sterols with acetic acid under reflux conditions are nearly same and could be expressed as r=(0.278 +0.002)xC(mol . L-1 . h-1); the effect of the catalyst in the presence of 2.5% to 5.0% (by mass) on the rate constant is below 5%; the rate constant of k decreases from 0.215h-1 to 0.105h-1 when content of water varying from 3.0% to 15.0% by volume.(2) The reaction between phytosterol and acetic anhydrideThe acetylation of phytosterol was studied and the effects of reaction temperature, reaction time, and reactant mass ratio on esterifying results were investigated. The product was characterized by FT-IR, HPLC and DSC methods. The experimental result show that the acetylization conversion of phytosterol could be more than 95.0% under the conditions of phytosterol and acetic anhydride based on the mass ratio of 1:10.0 at 90C for 0.5h; the yield of phytosterol could be above 92.0%.(3) The reaction between phytosterol and succinic anhydrideThe hemisuccination of B-sitosterol and succinic anhydride was studied. The proces更多还原