Preparation and characterization of thiourea-silica hybrid as heterogeneous catalyst

Abstract

Sodium silicate was prepared from rice husk ash (RHA), which then functionalized with 3-(chloropropyl)triethoxysilane via simple sol-gel technique to form RHACCl. The chloro group in RHACCl was replaced in iodo group to form RHACI. Thiourea was immobilized on RHACI to synthesize nanoheterogeneous catalyst labeled as RHATU-SO4H. The FT-IR analysis clearly indicated the presence of primary amine –NH2 and C-N absorption band. BET surface area measurement also showed that the surface area is 357 m2/g of catalyst with pore size distribution (2-20 nm) which falls within the mesoporous region. The elemental analysis has also proved the existence of nitrogen and sulfur in the structure of the catalyst. Upon application of RHATU-SO4H as a catalyst, the degradation of cellulose to glucose yields 81 % at 140 °C for 16 h. The synthesized catalyst is easy to synthesize, highly stable throughout hydrolysis of cellulose as well as reusability without loss of catalyst activity.