Zeolite-catalyzed dehydration of ethanol is an attractive economically feasible route for production of ethylene and butenes. The goal of this contribution is to monitor the intermediate species on the surface of “working” catalyst to rationalize the influence of the reaction conditions and zeolite characteristics on the dehydration pathways. With this respect the rates of diethyl ether (DEE) and ethylene formation in ethanol dehydration along with the quantification of the surface-intermediates (ethanol monomer and dimer) were simultaneously assessed under different reaction conditions in H-MFI zeolite. The reaction conditions (pressure, temperature, and ethanol conversion) control the population of surface intermediates and hence determine the dominant reaction mechanism. The results support the prevalence of dimer-assisted etherification at high ethanol pressures and enhanced contribution of ethoxide-mediated route with increasing the temperature. At high conversion, the DEE decomposition route producing ethylene was confirmed for H-MFI at 488 K along with ethoxide-mediated pathway.

沸石催化的乙醇脱水是生产乙烯和丁烯的一种有吸引力的经济上可行的途径。该贡献的目的是监测“工作”催化剂表面上的中间物质，以合理化反应条件和沸石特性对脱水途径的影响。因此，在H- MFI中，在不同的反应条件下，同时评估了乙醇脱水中乙醚（DEE）和乙烯形成的速率，以及表面中间体（乙醇单体和二聚体）的定量。沸石。反应条件（压力，温度和乙醇转化率）控制着表面中间体的数量，因此决定了主要的反应机理。这些结果支持在高乙醇压力下普遍存在二聚体辅助醚化反应，并随着温度的升高而增强了乙醇介导的途径的贡献。在高转化率下，确认了在488 K下H- MFI产生DEE的乙烯分解途径以及乙醇的介导途径。