The Acidic Property and Catalytic Activity of MoO3-SiO2-Al2O3

Article abstract of DOI:10.1246/bcsj.64.1926

The ternary oxide system MoO3-SiO2-Al2O3 was prepared by coprecipitation method.The pH of coprecipitation has been varied from pH = 2 to pH = 8 and its effect on the acidic properties of the ternary oxide acidic system was studied by butylamine titration.The MoO3-SiO2-Al2O3 prepared from highly acidic solution has low acid strength.The total acid amount of the ternary oxide decreased considerably at higher pH (>6) of coprecipitation.It was found that the total acid amount of MoO3-SiO2-Al2O3 containing 9.7 percent (by weight) of MoO3 and silica to alumina molar ratio 16.6 is very high compared with that of SiO2-Al2O3 of the same silica to alumina molar ratio.The acid strength of SiO2-Al2O3 is reduced by the incorporation of MoO3.Increase in calcination temperature increased the acid strength.The catalytic activity of MoO3-SiO2-Al2O3 was found to be very high for the alkylation of toluene with 2-propanol.The products are found to be o-cymene, p-cymene, and three isomers of diisopropyltoluenes.Reaction temperature >200 deg C, higher liquid hourly space velocity, and higher alcohol content in the feed decreased the total conversion of 2-propanol to isopropyltoluenes.The acidic property and catalytic activity of MoO3-SiO2-Al2O3 are not considerably reduced up to four successive regeneration cycles.