Thesis (M.Eng.)--Chulalongkorn University, 2009

In this study, gamma-Al₂O₃ and amorphous AlPO₄ were synthesized and tested in methanol dehydration reaction. Both gamma-Al₂O₃ and AlPO₄ catalysts showed increasing of activity when temperature direction during reaction test changed from step-up (150›200›250›300) to step-down (300›250›200›150). The effect of the presence of water product was studied by pretreatment of AlPO₄ catalyst with water various conditions. FT-IR and FT-Raman results indicated formation of P-OH group on the pretreated catalysts, which was one of intermediate for methanol dehydration. Amine titration also showed increasing of both strength and amount of acid sites on surface of the treated catalysts. The appropriate temperature on AlPO₄ catalyst was determined to be 200-250 degrees celsius for 10% mol of water in 5,300 h[superscript -1] GHSV for 15 minutes. On the other hand, the presence of water at 100 degrees celsius pretreatment became AlPO₄ poison which indicated by TGA and FT-Raman that physisorbed water could block the adsorption of methanol on catalyst active sites instead.