Progresses in study of solid acid catalysts for dimethyl ether synthesis through methanol dehydration

Study of solid acid catalysts used in the processes of methanol to dimethyl ether (MTD), especially mono-metal oxides, composite metal oxides and zeolites, was reviewed. In the present MTD processes, active aluminas and zeolites were usually employed. The active alumina, γ-Al₂O₃, mainly with weak or medium-strong acidic sites, showed excellent initial activity, but its reaction temperature was high and water resistance stability was low, which could be improved by addition of phosphate or silica to the catalyst. Zeolites with strong acidic sites exhibited outstanding low-temperature activity, but the selectivity to dimethyl ether was dependent on reaction temperature, which could be improved by selective poisoning with sodium ions. Furthermore, the status, problems and trends in research of the solid acid catalysts for MTD were discussed to provide a reference for design and preparation of high efficient and stable catalysts for industrial MTD process.