Epoxidation of ethylene with peracetic acid using heterogeneous catalyst
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Date
2018
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UMT, Lhr
Abstract
Ethylene Oxide (EO) is a generally utilized modern natural intermediate with an overall production of more than 22 million tons in recent years. It is one of the most important raw materials utilized in vast scale chemical productions and also an excellent disinfectant, sterilizing agent, and fumigant. Various processes were utilized for the commercial synthesis of EO but had not proved to be appropriate for a few reasons, including low proficiency and lower yield or selectivity of ethylene oxide per unit of ethylene feed consumed. So the idea for homogeneous liquid phase epoxidation of ethylene to produce EO using developed heterogeneous catalysts has been practically executed which yields high selectivity under gentle conditions. This was the first attempt to produce EO by homogeneous liquid phase epoxidation of ethylene using heterogeneous catalysts with peracetic acid (PAA), a strong oxidizing agent. Au/TiO2 catalyst was prepared in which Au was supported on TiO2 by the deposition-precipitation (DP) method, and its catalytic activity for ethylene epoxidation was tested. The results showed that Au/TiO2 have excellent performance for the selective oxidation of alcohols. The analyses of X-ray diffraction (XRD) and Brunauer-Emmett-Teller (BET) surface area, transmission electron microscopy (TEM), scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS) further showed that the presence of Au@TiO2 not only increased its surface area and restrained the growth of TiO2 crystallites, but could also enhance the microstrain of TiO2. All catalysts displayed far better catalytic activity for EO formation, however maximum EO selectivity (94.53 %), EO yield (42.69%) and maximum ethylene conversion per pass (45 %) were obtained utilizing AuTiO2-4 at 6h reactivity time, 50 bar and 60 oC by using PAA as oxidant.