A new method of ethanol synthesis from dimethyl ether and syngas in a sequential dual bed reactor with the modified zeolite and Cu/ZnO catalysts

Ethanol was directly synthesized from dimethyl ether (DME) and syngas (CO + H2) with the combination of Cu-modified H-Modernite (H-MOR) zeolite catalyst and metallic Cu/ZnO catalysts in a dual-catalyst bed reactor. The methyl acetate (MA) was firstly formed by DME carbonylation on the upper zeolite catalyst layer, and then was subsequently hydrogenated on the lower Cu/ZnO catalyst layer to be converted into ethanol accompanying with methanol. A copper doped H-MOR catalyst prepared by ion-exchange method exhibited better catalytic activity compared with the pure H-MOR catalyst in the single DME carbonylation reaction, and the influence of reaction temperature was investigated in detail, confirming that the optimal reaction temperature for this copper doped H-MOR catalyst was 493 K. For ethanol synthesis in the dual catalyst bed reactor, the combination of copper doped H-MOR catalyst with Cu/ZnO catalyst effectively improved the DME conversion, enhanced the ethanol selectivity in the final products remarkably, if compared with the combination of pure H-MOR catalyst with Cu/ZnO catalyst.