Relative roles of methanol synthesis and solid acid catalysts in the direct DME synthesis from syngas

The Cu/ZnO/Al₂O₃ catalysts with 13.0 and 30.6 m²Cu/g were designated as HM (highly active catalysts for methanol synthesis) and LM (low active catalysts for methanol synthesis), respectively. γ-Al₂O₃ and η-Al₂O₃ were designated as LD (low active catalysts for methanol dehydration) and HD (highly active catalysts for methanol dehydration), respectively. Four catalytic systems (LMLD, LMHD, HMLD, and HMHD) were prepared by admixing methanol synthesis catalysts and methanol dehydration catalysts. The syngas to dimethyl ether (DME) (STD) reaction was conducted at a GHSV of 6000 mL/g_cat/h, 42 atm, and 250 °C. The activity of LMLD was almost same as that of LMDH, indicating that the activity of solid acid catalysts did not influence the STD reaction on the admixed catalysts using LM. On the other hand, the activity of HMHD was much higher than that of HMLD, indicating that the solid acid catalysts controlled the STD reaction on the admixed catalysts using HM.