甲醇气相脱水制二甲醚催化剂研究进展

Development in the catalysts for vapor-phase dehydration of methanol to dimethyl ether

甲醇气相脱水制二甲醚反应为固体酸催化反应,常用的固体酸催化剂有γ-Al2O3和分子筛类。γ-Al2O3表面存在弱酸中心或中等强度酸中心,催化剂有较好的初始催化活性,但活化所需的反应温度较高,耐水稳定性差;分子筛类催化剂表面有许多强酸性位,低温下催化活性较高,但在高温反应条件下易产生烃类副产物和积炭,热稳定性差。为改善这两类催化剂的催化性能,对催化剂进行了各种改性研究,改性后催化剂的活性、选择性和稳定性均有一定程度提高。综述了近年来在γ-Al2O3和分子筛催化剂上进行的改性研究,总结并展望了甲醇脱水催化剂的发展方向。

Dimethyl ether can be synthesized by vapor-phase dehydration of methanol over solid acid catalysts. Y-A12O3 and zeolites are employed as the catalysts.Y-A12O3 with weak or medium-strong acidic sites on its surface possesses good initial activity, high reaction temperature and low water-resistance stability. Zeolite catalysts with many strong acidic sites on their surface exhibit excellent low-temperature activity,but easily form hydrocarbons and coke at higher temperatures and show poor heat-resistance stability. In order to improve their catalytic performance, the modification research on Y-A12O3 and zeolite catalysts were carried out. The catalytic activity, selectivity and stability of the catalysts after modification were enhanced to a certain extent. The recent research progress in modification of Y-A12O3 and zeolite catalysts was reviewed in this paper, and the development trends of the catalysts for methanol dehydration were outlined.