Synergetic effects of Sn and Ti incorporated in MWW zeolites on promoting the oxidative hydration of ethylene with H2O2 to ethylene glycol

Although the titanosilicate zeolite catalyzed one-pot oxidative hydration of ethylene with hydrogen peroxide (H2O2) to ethylene glycol (EG) takes advantages of step-saving and facile operation, both H2O2 utilization efficiency and EG yield are relatively low. In the present work, Sn-doped Ti-MWW zeolites, named Sn-Ti-MWW, were developed for this oxidative hydration, showing the much higher H2O2 utilization efficiency and EG yield, compared to Ti-MWW. The extensive characterizations of Sn-Ti-MWW zeolites, in combination with Density Functional Theory (DFT) calculations, verify that the doping of Sn into Ti-MWW leads to the higher electropositivity of the Ti species, resulting in the stronger acidity of the zeolite, which is helpful to the H2O2 utilization and EG production. In addition, although the catalyst deactivation is observed due to the deposition of the bulky byproducts onto the active sites and/or into the zeolite micropores, the simple calcination of the used catalyst readily restores its catalytic activity. Therefore, it is anticipated that the developed Sn-Ti-MWW catalyst might be applicable in the one-pot oxidative hydration of ethylene with H2O2 to EG industrially.