超低酸高温催化葡萄糖醇解产物的分布规律  

Products Distribution of Glucose through Ethanolysis Reaction Catalyzed by Extremely Low Acid under High Temperature

作　　者：常俊丽[1] 白净[1,2] 常春[1,2] 赵世强[1] 李洪亮[1,2] 方书起[1,2] 

机构地区：[1]郑州大学化工与能源学院,河南郑州450001 [2]生物质炼制技术与装备河南省工程实验室,河南郑州450001

出　　处：《林产化学与工业》2015年第6期8-14,共7页Chemistry and Industry of Forest Products

基　　金：国家自然科学基金资助项目(21176227);河南省教育厅科学技术重点研究项目(14A530002)

摘　　要：以葡萄糖为原料,硫酸(≤0.1%)为催化剂,研究了在乙醇、乙醇/共溶剂体系中催化葡萄糖醇解的产物分布规律。在葡萄糖质量浓度20 g/L,反应温度200℃,硫酸质量分数0.1%的条件下反应120 min,液相主要产物为乙酰丙酸乙酯(EL),得率40.46%。比较9种乙醇/共溶剂体系对葡萄糖醇解的影响,选择正己烷作为共溶剂进一步考察了乙醇/正己烷对葡萄糖醇解过程的影响,结果表明产物分布规律与其在乙醇溶剂体系中相似,正己烷的引入不能有效提高EL的得率,但有利于中间产物5-乙氧基甲基糠醛(EMF)的积累,并减弱其进一步水合生成EL。反应温度低或高温反应时间较短时,有利于葡萄糖转化生成乙基葡萄糖苷(EG);适当提高反应温度,延长反应时间,有利于EL的生成。在整个反应过程中乙酰丙酸(LA)和5-羟甲基糠醛(HMF)的生成量较少,根据产物分布规律,提出了葡萄糖在乙醇/正己烷中超低酸催化降解的反应路径。The distribution of products from glucose catalyzed by extremely low sulfuric acid（ ≤0.1% ）in ethanol and ethanol/co- solvent medium was investigated. The results showed that ethyl levulinate （EL） was the main product in the liquid with a yield of 40.46% under the reaction conditions of glucose concentration 20 g/L, reaction temperature 200 ℃, sulfuric acid concentration 0.1% and reaction time 120 min. The influence of nine kinds of ethanol/solvent system was compared, and the effect of using n-hexane as a co-solvent was further investigated. Moreover, the effect of using n-hexane as a co-solvent was investigated, and similar results of the distribution of products were obtained compared with the results in pure ethanol system. The addition of n-hexane could not increase the yield of EL effectively, but it can improve the concentration of intermediate of 5-ethoxymethylfurfural （EMF）. It also can prevent EMF of further hydration to form EL. Ethyl glueoside（EG） was easily obtained from glucose with lower or higher reaction temperature accompanied with shorter reaction time. Increment of the reaction temperature and reaction time has positive effect on generation of EL. The byproducts, such as levulinie acid （ LA ） and 5-hydroxymethylfurfural （ HMF ） , was accounting for a minority part of the product during the reaction process. According to the distribution of products, a reaction pathway for the extremely low sulfuric acid catalyzed conversion of glucose in ethanol/n-hexane medium was proposed.

关 键 词：葡萄糖 乙酰丙酸乙酯 超低酸 共溶剂 

分 类 号：TQ35[化学工程]