A facile ethanol fuel synthesis from dimethyl ether and syngas over tandem combination of Cu-doped HZSM35 with Cu-Zn-Al catalyst

Abstract

Ethanol (EtOH) is a significantly useful fuel and fuel additive, besides as one of important basic chemicals. To date, EtOH is mainly produced by ethylene hydration method and biomass fermention method. In this report, we realized a facile ethanol synthesis route with dimethyl ether (DME) and syngas (CO+H2) as feedstocks in a dual-catalyst bed reactor over the tandem ferrierite (HZSM35) and Cux-Zny-Alz catalysts. The HZSM35 and Cux-Zny-Alz were prepared by using hydrothermal synthesis method and co-precipitation method, respectively. Firstly, methyl acetate (MA) was produced by DME carbonylation with CO on HZSM35 catalyst. Thereafter, the formed MA was hydrogenated to EtOH and methanol (MeOH) on Cux-Zny-Alz catalyst. By investigating reaction temperature in detail, the DME carbonylation reaction at 220°C realized the highest MA productivity of 638.4mmolkg−1h−1. To further improve DME carbonylation performance, Cu-doped HZSM35 (Cu/HZSM35) catalyst with varied Cu loading amount was prepared by ion exchange method. The Cu0.55/HZSM35 with 0.55wt% loading amount exhibited higher DME conversion (26.5%) than pure HZSM35 (20.4%). Ethanol synthesis was facilely realized in a dual-catalyst bed reactor over tandem HZSM35 and Cu-based catalysts. By using the optimized catalysts combination consisting of Cu0.55/HZSM35 catalyst and Cu1-Zn1-Al0.1 catalyst, we got higher DME conversion of 27.1% and EtOH productivity of 829.5mmolkg−1h−1.