Hydroformylation of olefins by Au/Co3O4 catalysts
Hydroformylation of olefins by Au/Co3O4 catalysts
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DOI：
10.1016/j.apcatb.2009.08.021
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发表时间：
2009-11
影响因子：
22.1
通讯作者：
Xiaohao Liu;Baoshan Hu;K. Fujimoto;M. Haruta;M. Tokunaga
中科院分区：
文献类型：
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作者：
Xiaohao Liu;Baoshan Hu;K. Fujimoto;M. Haruta;M. Tokunaga
在温和条件下（100-140℃，3-5MPa）研究了负载型金催化剂上烯烃的氢甲酰化反应。在Au/AC（活性炭）、Au/PVP（聚乙烯吡啶酮）、Au/Al2O3、Au/TiO2、Au/Fe2O3、Au/ZnO、Au/ ceo2和Co3O4反应中，1-烯烃基本保持不变，主要产物为异构化烯烃或氢化石蜡。相比之下，沉积在co3o4上的金纳米颗粒在氢甲酰化反应中具有非常高的催化活性，对所需醛的选择性超过85%。烯烃的氢甲酰化反应在140℃以下优先进行，在140℃以上烯烃的反应逐渐向异构化和加氢转变。氢甲酰化反应的活性和选择性很大程度上取决于烯烃的分子结构，这可能是由于空间约束的原因，因为内部烯烃相对不适合通过插入CO形成烷基和随后的酰基。Au/ co3o4催化剂可以通过简单的倒装回收，催化活性略有下降，但循环次数增加，这比均相催化剂有很大的优势。金纳米粒子的作用是在温和的反应条件下将氢分子解离成原子，将co3o4还原为金属钴。
The hydroformylation of olefins over supported gold catalysts in an autoclave reactor under mild conditions (100–140°C, 3–5MPa) has been studied. Over Au/AC (activated carbon), Au/PVP (polyvinylpyrrolidone), Au/Al2O3, Au/TiO2, Au/Fe2O3, Au/ZnO, Au/CeO2and Co3O4, 1-olefin mainly remained unchanged and the major products were isomerized olefins or hydrogenated paraffin. In contrast, Au nanoparticles deposited on Co3O4led to remarkably high catalytic activities in hydroformylation reaction with selectivities above 85% to desired aldehydes. The hydroformylation of olefins proceeds preferentially at temperatures below 140°C, above which the reactions of olefins gradually shifted to isomerization and then to hydrogenation. It appeared that the activity and selectivity of hydroformylation reaction strongly depend on the molecular structure of olefins, which could be ascribed to steric constraints as internal olefins are relatively inappropriate to form alkyl group and subsequent acyl group by insertion of CO. The Au/Co3O4catalyst can be recycled by simple decantation with slight decrease in catalytic activity along with an increase in recycle times, which is a great advantage over homogeneous catalysts. The role of gold nanoparticles can be assumed to dissociate hydrogen molecule into atomic species which reduce Co3O4to Co metal under mild reaction conditions.