ZSM-5分子筛转化乙醇为乙醚的研究

用原位红外技术、程序升温热脱附和X射线光电子能谱研究了乙醇和乙醚在HZSM-5和PZSM-5上的吸附及表面状态, 并与催化乙醇为乙醚的活性和选择性相关联. 结果表明, 乙醇与质子酸中心作用形成吸附态乙醇, 该吸附态乙醇与气相乙醇反应生成吸附态乙醚, 然后从表面脱附. 磷的掺入能有效抑制积炭发生.

Studies on the conversion of ethanol to diethyl ether on ZSM-5 type zeolites

HZSM-5 and phosphorus-modified ZSM-5 zeolites have been studied by means of in situ IR spectroscopy, temperature- desorption and XPS for adsorption behavior and surface state, by flow method for measuring catalytic activity and selectivity of conversion of ethanol to di-Et ether. On ZSM-5 type zeolites having Broensted acid centers, the mechanism of the formation of di-Et ether may be supposed as follows: ethanol mol. is adsorbed on the hydroxyl group of Al-OH to form adsorbed species which then reacts with another mol. of ethanol in the gas phase to form an adsorbed di-Et ether mol., desorption of the latter from the catalyst surface furnished the final product in free state. The addition of phosphoric acid prevents coke deposit.