响应面法优化甘蔗糖蜜酸催化水解制备乙酰丙酸

Application of Response Surface Methodology to Optimize Production of Levulinic Acid by Acid Catalytic Hydrolysis of Cane Molasses

摘要:

在甘蔗糖蜜酸催化水解制备乙酰丙酸的过程中，以乙酰丙酸（levulinic acid, LA）产率为考察对象，在单因素实验基础上，考察了反应时间、糖蜜浓度、催化剂浓度比、反应温度的作用。采用Box-Benhnken中心组合试验原理和响应面分析法（RSM）对乙酰丙酸制备条件进行优化。结果表明，建立的二次多项式模型回归性显著而失拟项不显著，模型拟合性良好。各因素对LA产率有显著性影响，依次为：催化剂浓度比>反应温度>反应时间>糖蜜浓度。实验最终确定乙酰丙酸最佳制备条件为：反应时间5 h、糖蜜浓度40 wt%、催化剂浓度比23.40:1、反应温度151℃。该条件下进行三次重复试验，乙酰丙酸的实际平均产率为30.11 wt%，与预测值30.96 wt%相对偏差0.85 wt%，模拟可靠。

Abstract:

In the process of production of levulinic acid by acid catalytic hydrolysis of cane molasses,taking the yield of levulinic acid as the main indicator, single factor and combined effects of reaction time, the concentration of molasses, molasses-catalyst mass ratio , temperature were evaluated based on single-factor experiments. Box-Benhnken center combination experimental principle and response surface methodology(RSM) were adopted to optimize the preparation conditions of levulinic acid. A quadratic polynomial regression model was established to predict the LA yield. The results showed that the regression of this model was significant while the lack of fit was not significant, which indicated the model fitted well with experimental data. Each factor alone could significantly influence the yield of LA, and the order was molasses-catalyst mass ratio > temperature >effects of reaction time>the concentration of molasses. The highest LA yield was obtained under the optimal condition of 40 wt % molasses, 23.40:1 molasses - H2SO4 mass ratio at 151℃ for 5 h. The average yield of LA reached 30.11 wt% under the optimum conditions for three times. Compared with the predicted value of 30.96 wt%, the relative deviation was only 0.85 wt% , which proved the model was reasonable and feasible.