Recent use of rice husk ash silica as an efficient solid catalyst: a review

This review is mainly focused on the recent development of rice husk utilization for the efficient immobilization of organic molecules. It was pointed out that sodium silicate precursor was prepared in large amounts from rice husk ash. Moreover, a new route was designed for the extracted sodium silicate through a purely homogenous method in-situ reaction of 3-(chloropropyl)triethoxysilane (CPTES) with silica. The product was solid silica with chloride end groups. The silica-chloride end groups are the cornerstone for the design of heterogeneous catalyses with the specific functional groups for different purposes. These functionalized silica catalysts have attracted widespread attention due to their good physical and catalytic properties in a large variety of chemical reactions.