Preparation of Synthetic Catalysts

Silica/alumina catalysts were carefully prepared by precipitating alumina from an aluminum salt at pH 7 onto a freshly prepared silica hydrogel. The precipitate 

Early silica/alumina catalysts contained 10-13% AI2O3, which, at the time, appeared to be optimum. Increased alnmina content had httle effect on activity and produced gasoline with a lower octane nnmber, while forming more coke. Powdered silica/alumina catalysts were used until spray-dried microspheroidal particles were introduced in 1948. 

---