Abstract:

Using tert-butanol as the reaction solvent, aqueous hydrogen peroxide was fused with other hydrophobic reaction substrates to construct a single-phase reaction system for epoxidation of α-pinene to replace the traditional organic-water “two-phase” system. Firstly, the single-phase system was optimized in shaking flask. When the concentration of α-pinene was 0.3mol/L, the optimum concentration of ethyl acetate and hydrogen peroxide was 3.5mol/L and 0.5mol/L, respectively, trisodium citrate was selected as the acid-trapping reagent, and the epoxidation conversion and yield at 40℃ for 90min were 92% and 88%, respectively. Under this process conditions, Novozym435 could still maintain 64% relative activity after being reused 6 times. Then, based on the shaking flask experiment, a continuous stirred tank reactor (CSTR) was constructed, the optimal operating conditions of the reactor were studied, and its long-term operating performance was tested. The results showed that: when the amount of Novozym435 enzyme was 2.0g, the concentration of hydrogen peroxide was 0.5mol/L and the residence time was 3h, the tank reactor had the best operating effect with a conversion of 83% and a yield of 79%. Under these conditions, the reactor could still maintain more than 70% conversion and more than 55% yield after 10 days of continuous operation.

Key words: solvents, pinene, catalysis, epoxidation, chemical reactor

摘要：

采用叔丁醇作为α-蒎烯环氧化的反应溶剂，使过氧化氢水溶液和其他疏水性反应底物形成均相，构建单相体系以代替传统有机-水“双相”系统。首先在摇瓶中对单相体系进行优化，在α-蒎烯浓度为0.3mol/L时，乙酸乙酯的最适浓度为3.5mol/L，过氧化氢的最适浓度为0.5mol/L，束酸剂为柠檬酸三钠，在40℃下，反应90min，环氧化转化率为92%，收率为88%。此工艺条件下Novozym435重复使用6次后，仍保持64%的相对活力。然后以摇瓶实验为基础，构建了一种连续搅拌釜式反应器（CSTR），探索反应器的最适运行条件，测试了其长期运行性能，结果表明：当Novozym435酶量为2.0g、过氧化氢浓度为0.5mol/L、停留时间为3h时，釜式反应器的运行效果最好，其转化率可达83%，收率可达79%，在此条件下反应器连续运行十天后依然可以保持70%以上的转化率和55%以上的收率。

关键词: 溶剂, 蒎烯, 催化, 环氧化, 化学反应器