Synthesis TS-1 nanozelites via L-lysine assisted route for hydroxylation of Benzene

Abstract

L-lysine is used as a crystallization regulator, and a two-step synthesis method is adopted in a concentrated gel system, which provides a new route to synthesize of nano-sized TS-1 zeolite. The new synthesis strategy was used to successfully synthesize TS-1 zeolite with a particle size less than 100 nm. The rate of crystal nucleation is faster than the crystal growth at the low temperature in the first step. Introduction of L-lysine can prevent crystal growth to form nano-sized TS-1 zeolite at the high temperature in the second step. Meanwhile, L-lysine decrease the pH value of the gel system, which is favorable for Ti atoms to incorporate the TS-1 framework. TS-1 nanozeolite can effectively reduce the diffusion resistance, and nanozeolite has a large specific surface area and high stability. Therefore, TS-1 nanozeolite exhibits the excellent catalytic performance during the hydroxylation of benzene. The conversion of benzene has been greatly improved and the types of by-products are effectively reduced. The conversion of benzene reached 50.2%, and the yield of phenol was 30.8% without by-product benzoquinone. TS-1 nano-zeolite as a catalyst for benzene hydroxylation shows great potential in industrial application.