Thesis (M.Eng.)--Chulalongkorn University, 2006

This research has studied the catalytic activity of titanium silicalite-1 (TS-1) catalysts modified by Fe Al Co and V were synthesized, characterized and tested in the hydroxylation of benzene by hydrogen peroxide and the effects of pretreatment with nitric acid aqueous solution on the catalytic activity of catalysts. The results of the reaction show that the Fe Al Co and V incorporated in TS-1 framework promoted the catalytic activity higher than TS-1. Especially, the Co-TS-1 catalyst has the highest catalytic activity. After the catalysts were pretreated by nitric acid aqueous solution, the framework structure of catalyst is not destroyed and titanium in the framework is not removed. But, the extra-framework can be removed partly. As a result, the activity of the pretreated catalysts is improved. The catalytic activity of the investigated catalyst is in the following order Co-TS-1 > V-TS-1 > Fe-TS-1 > A1-TS-1 > TS-1. Co-TS-1 is found to be the best one due to it cause the lowest H[subscript2]O[subscript2] decomposition and has the least phenol product deposite on the surface.