Modification of acid properties and catalytic properties of AlPO4 by hydrothermal pretreatment for methanol dehydration to dimethyl ether

摘要: Abstract An amorphous AlPO 4 catalyst prepared by precipitation method was subjected to pretreatment with 10 mol% water vapor at 100–300 °C for 15 min prior activity tests in the dehydration of methanol dimethyl ether (DME). The catalysts pretreated 200–300 °C exhibited higher conversion than non-treated while one treated a lower temperature 100 °C showed activity. As revealed FT-IR and FT-Raman results, there an increase lattice hydroxyls on hydrothermally form P-OH group (weak Bronsted acid sites). Amine titration using Hammett indicators confirmed both strength number sites these catalysts. However, hydrothermal may result poisoning weakly bonded molecules instead so that obtained. More 99% selectivity DME achieved this study.