固体酸SO_4^(2-)/ZrO_2催化蔗糖制备乙酰丙酸乙酯

Conversion of sucrose to ethyl levulinate catalyzed by solid acid SO_4^(2-)/ZrO_2

采用沉淀-浸渍法制备了一系列不同焙烧温度的SO42-/ZrO2固体酸催化剂,考察了其催化转化蔗糖制备乙酰丙酸乙酯的反应活性。反应过程条件如催化剂用量、反应温度、反应时间以及催化剂重复使用对产物得率的影响进行了研究。结果表明合适的工艺条件为:催化剂焙烧温度600℃、催化剂添加的质量分数为2.5%、反应温度200℃和反应时间2 h。该条件下蔗糖几乎完全转化,乙酰丙酸乙酯得率(摩尔分数)最高达36.6%。回收的SO42-/ZrO2催化剂焙烧后在多次重复使用过程中仍然表现出较好的催化活性。X射线衍射仪(XRD)和NH3-程序升温脱附法(NH3-TPD)分析表明,随着重复使用次数的增加,SO42-/ZrO2的晶形结构基本保持不变,酸强度和总酸量稍微有所下降,主要酸性仍保留。本研究为生物质基化学品乙酰丙酸乙酯的制备提供了一条有效的、环境友好的途径。

A series of solid acid catalysts SO2-/ZrO2 with different calcination temperature are prepared by precipitation and impregnation method for ethyl levulinate production from sucrose in ethanol. The effects of various reaction parameters such as catalyst dosage, reaction temperature, reaction time and catalyst reuse cycle on the yield of product are studied. The results show that the sucrose is completely consumed and the yield of ethyl levulinate can reach ca. 36. 6 mol%. The optimum parameters are shown as follows：600~C of catalyst calcination temperature, 2. 5 wt% of catalyst dosage ,200℃ of reaction temperature and 2 h of reaction time. The recovered catalyst after calcination is found to remain high catalytic activity after being reused five times. XRD and NH3-TPD results indicate that, with the increase in the times of reuse, catalyst crystallization structure is preserved. The acid strength and total amounts of acid decrease slightly. But the main acidity of catalyst is still unchanged. This research provides an effective and environmental friendly way for the production of the biomass-based chemicals like ethyl levulinate.