微波固相法制备OMS-2基固体酸及其催化合成乙酸异戊酯

Preparation of OMS-2 Based Solid Acid under Microwave Irradiation and Its Application in Synthesis of Isoamyl Acetate

以乙酸和异戊醇为原料,微波固相法制备的SnCl4(FeCl3)/OMS-2为固体酸催化剂,合成乙酸异戊酯。考察了活性组分种类、负载量等因素对酯化反应的影响。采用X射线衍射、扫描电镜以及比表面积测试等技术对样品的结构和形貌进行了表征。并用红外和折光率测试对酯化产品进行了验证。结果表明,微波固相法较之常规的固相法可以使活性组分SnCl4或FeCl3在氧化锰八面体分子筛表面的分散更加均匀,催化剂具有更加纤细的外形和更大比表面积,因而具有更高的酯化活性。在酸醇摩尔比为1:1.5,催化剂用量为反应液质量的1%,甲苯作为带水剂,反应温度110～120℃条件下,酯化活性随着活性组分SnCl4或FeCl3在OMS-2表面的负载量的变化呈火山状变化,最佳负载量为每克载体负载0.005mmol活性组分。OMS-2表面负载SnCl4时,酯化活性更佳,最大酯产率为84.8%。

Isoamyl acetate was synthesized from acetic acid and isoamyl alcohol with SnCl4 （FeCl3 ）/ OMS -2 as solid acid catalyst prepared by microwave irradiation. The effects of active components and their mole loading were evaluated. The structure and surface morphology of the catalysts were characterized by XRD, SEM and the surface area analysis. The structure of the reaction product was identified by means of FTIR and refractive index analysis. The results show that, compared with the catalyst synthesized by the conventional solid-state reaction, the catalyst by the microwave irradiation has the relatively more uniform active component dispersion on the carrier, a finer needle morphology and larger surface area, thus shows a better activity. Under the conditions of a mole ratio of acetic acid to iso-amyl alcohol 1：1.5,catalyst addition ：1% mass of the raw materials, toluene as water-entrainer, reaction temperature 110 - 125 ℃, the esterification activity shows a volcano plot with the loading of SnCl4 or FeCl3 on OMS -2. The best loading is 0. 005 mmol in every gram of carrier. The best esterification activity was found on SnCl4/OMS - 2 with an isoamyl acetate yield of 84. 8%.