Abstract:

In order to explore the feasibility of one-pot preparation of methyl levulinate (MLA)from biomass catalyzed by dilute sulfuric acid in near-critical methanol, the kinetics of MLA production were investigated at initial glucose concentration of 10—30 mg·ml^-1, temperature range from 160 ℃ to 190 ℃, and sulfuric acid concentration between 0.01—0.06 mol·L^-1.The results show that reaction temperature has a significant effect on the selectivity of MLA and higher yield of MLA is obtained at higher temperature.With the first-order kinetic equations, the activation energies evaluated are 107.5 kJ·mol^-1 and 68.4kJ·mol^-1, and the reaction orders to H⁺ concentration are 0.981 and 0.953 for main and side alcoholysis reactions of glucose, respectively.The paper demonstrates that the one-pot process is promising for MLA production catalyzed by dilute sulfuric acid in near-critical methanol.

Key words:

葡萄糖, 乙酰丙酸甲酯, 近临界甲醇, 醇解, 动力学

摘要： 为了探索近临界甲醇中稀硫酸催化下生物质醇解一步法制备乙酰丙酸甲酯方法的可行性，本文以葡萄糖为模型物质，系统地测定了葡萄糖初始浓度10～30 mg·mL-1、温度160～190 ℃、硫酸浓度0.01～0.06 mol·L^-1范围内葡萄糖醇解反应中乙酰丙酸甲酯产物生成反应动力学数据。实验结果表明，反应温度对葡萄糖的醇解选择性影响比较显著，提高温度有利于提高乙酰丙酸甲酯的产率。采用一级反应动力学模型对数据进行了拟合，得到主、副反应的活化能分别为107.5 kJ·mol^-1和68.4 kJ·mol^-1；葡萄糖醇解的主、副反应对[H⁺]分别为0.981级、0.953级。研究结果表明近临界甲醇中稀硫酸催化醇解生物质一步法制备乙酰丙酸甲酯是一条很有发展前景的工艺路线。

关键词:

葡萄糖, 乙酰丙酸甲酯, 近临界甲醇, 醇解, 动力学