Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
42219 | Applied Catalysis A: General | 2010 | 5 Pages |
An amorphous AlPO4 catalyst prepared by precipitation method was subjected to pretreatment with 10 mol% water vapor at 100–300 °C for 15 min prior to activity tests in the dehydration of methanol to dimethyl ether (DME). The catalysts pretreated at 200–300 °C exhibited higher methanol conversion than the non-treated catalyst while the one treated at a lower temperature of 100 °C showed lower activity. As revealed by FT-IR and FT-Raman results, there was an increase of lattice hydroxyls on the hydrothermally treated catalysts in the form of P-OH group (weak Brønsted acid sites). Amine titration using Hammett indicators confirmed the increase of both strength and number of acid sites on these catalysts. However, hydrothermal pretreatment at 100 °C may result in catalyst poisoning by weakly bonded water molecules instead so that lower catalyst activity was obtained. More than 99% selectivity to DME was achieved on both non-treated and hydrothermally treated AlPO4 catalysts in this study.
Graphical abstractHydrothermal treatment with 10 mol% water vapor at 200–300 °C for 15 min resulted in an increase of both acid strength and number of acid sites on the AlPO4 catalysts. As a consequence, their catalytic activities in dehydration of methanol to dimethyl ether (DME) were enhanced with no change in the product selectivities (>99% DME).Figure optionsDownload full-size imageDownload high-quality image (93 K)Download as PowerPoint slide