微波辅助ZrO_2-SO_4^(2-)/SBA-15催化合成棕榈酸甲酯

Catalytic synthesis of methyl palmitate over ZrO_2-SO_4^(2-)/SBA-15 catalyst under microwave irradiation

以三嵌段醚共聚物P123作为模板剂、正硅酸乙酯为硅源,合成介孔分子筛SBA-15。以SBA-15为载体,利用尿素水解法制备ZrO2-SO24-改性的固体酸催化剂,对其进行表征。实验结果表明,合成的固体酸催化剂具有典型的介孔结构特征。将催化剂应用于微波法催化合成棕榈酸甲酯,考察反应时间、反应温度、辐射功率、酸醇物质的量比和催化剂用量对酯化率的影响,结果表明,在n(十六酸)∶n(甲醇)=1∶15、SZ/SBA-15催化剂用量0.8 g、反应时间20 min、反应温度40℃和微波辐射功率400 W条件下,酯化率可达87.70%,微波反应时间较传统合成方法大大缩短。

SBA-15 mesoporous molecular sieves were prepared by hydrothermal method using triblock copolymer Pluronic P123 （EO20POToEO20） as the template agent and tetraethoxysilane（TEOS） as silicon source. Using the as-prepared mesopsrous SBA-15 as the support and Zr（ NO3 ）4 · 5H20 as zirconium source ,ZrO2/SBA-15 was prepared by homogeneous urea hydrolysis method. ZrO2-SO^2-4/SBA-15 catalyst was prepared by using H2SO4 as the impregnating solution and impregnation method,and characterized by means of XRD and low temperature nitrogen adsorption-desorption. The catalyst was used for microwave- assisted synthesis of methyl palmitate. The influence of reaction time, reaction temperature, microwave power, molar ratio of palmitic acid to methanol and catalyst dosage on esterification rate was investigated. The results showed that the as-prepared catalyst possessed typical characteristics of mesopsrous structure ; the conversion rate of palmitic acid of 87.70% was attained under the reaction condition as follows： n （palmitic acid ）： n （ CH3 OH） = 1： 15, catalyst temperature 40 ℃ and microwave power 400 microwave reaction time was reduced greatly. dosage O. 8 g, microwave irradiation W. Compared with the traditional time 20 min, reaction synthesis method, the