乙醇在杂多酸上的氧化、脱水和程序升温脱附研究

合成了两个系列具有Keggin结构的12-钒钼磷酸和钨钼磷酸,研究了它们对乙醇氧化、脱水的催化反应。借助程序升温脱附技术研究了反应物及产物乙醇、乙烯、乙醚等在样品上的程脱作用。讨论了钨、钒取代部分钼原于后对杂多酸酸性及氧化性能的影响。

OXIDATION,DEHYDRATION AND TPD STUDIES OF ETHANOL ON HETEROPOLY ACIDS

Two series of heteropoly acids with keggin structure namely H3 nPMo12_nVaO40 (n=0,1,2,3) and H3PMo12-aWO40(n = 0,3,6,9,12) were prepared by common ethyl ether extraction method and identified by IR and TG-DTA analysis.The catalytic oxidation and dehydration of ethanol and the TPD of ethanol,ethylene,ethyl ether over HPA were studied.The replacement of Mo atoms in the Keggin unit by V atoms decreases the thermal stability, dehydration activity of the sample and increases its ability of deep oxidation to form CO and CO2 ,but the formation rate of acetaldehydc of the sample does not change .In contrast, the thermal stability and the dehydration activity are greatly enhanced by the replacement of Mo with W,but the formation rate of acetaldehyde does not decrease.It is suggested that both Mo and W atoms in the Keggin unit are involved in the redox process.