Cu/Sn-β Catalyst Enabling the One-Step Synthesis of Methyl Acetate from Methanol Alone via Dehydrogenation Coupling

Abstract

Methyl acetate (MA) can be directly synthesized via a methanol dehydrocoupling reaction, which is attractive but urgently calls for a groundbreaking catalyst. Herein, we report a Cu/Sn-β system with Sn−Cu synergistic catalysis, enabling the one-step MA synthesis from methanol alone. Over the 3Cu/Sn-β-30 (Si/Sn molar ratio of 33, Cu loading of 3 wt %), a maximum MA space−time yield of 1.4 mol MA kg cat −1 h −1 is obtained with 4.1% methanol conversion and 56.4% MA selectivity at 220 °C. Electron transfer from Cu species to framework-confined Sn occurs and thus increases and stabilizes Cu + sites. Lewis-acidic Sn(framework)/Cu + pairs, with the assistance of Cu 0 dehydrogenation, can transform a methanol molecule into bridged-adsorbed CH 2 O*. The C−C coupling of CH 2 O* with CH 3 O* on another Sn site proceeds to form CH 3 CHO* by leaving H on Cu + and O (C−O bond cleavage of CH 3 O*) on that Sn site. The CH 3 CHO* subsequently condenses with CH 3 O* adsorbed on the Cu 0 site to form MA.