Effect of Phosphorus Impregnation on γ-Al₂O₃ for Methanol Dehydration to Dimethyl Ether

Dimethyl ether has gained great attention by Indonesian Government since it will be used for the substitution for liquid petroleum gas. This work was aimed to study the effect of phosphorus addition on γ-Al₂O₃ catalyst for methanol dehydration to DME synthesis. The catalysts were prepared using sonication-assisted impregnation. The modified catalysts were characterized (XRD, BET, and NH₃-TPR analysis), and their activity was tested in bench scale reactor. The results showed that the 5%P/γ-Al₂O₃ catalyst had medium acidity which was good for dehydration of methanol to DME. The surface area, pore volume, and pore diameter were measured as 132 m²/g, 0.42 mL/g, and 127 Å, respectively. The activity test was carried out at 240–280 °C, atmospheric pressure, and GHSV 2,142 h⁻¹. The 5%P/γ-Al₂O₃ catalyst exhibited good performances at a temperature of 240 °C with 42% of methanol conversion, 18% of yield of DME, and 75% of selectivity of DME. Methanol dehydration using modified 5% P/γ-Al₂O₃ did not produce H₂ by-products and other compounds which were produced during methanol dehydration with unmodified γ-Al₂O₃.