Synthesis, characterization of nanostructured sulfated Zirconia@silica catalyst using green chemistry and its catalytic application in one pot isomerization of n-alkane

Abstract

Nano structured sulfated zirconium-sillicon binary oxides were synthesized in different mole-ratios of Zr^4±:Si^4±, 2:1 (SZS-1), 1:1 (SZS-2) and 1:2 (SZS-3), by a simple precipitation chemical method using green chemistry. The preparation of the catalysts from rice husk that is a waste product is highly exclusive and unique. Evaluation of these catalysts was carried out in a batch reaction system at normal temperature and pressure as well as at high temperature –flow-reactor during the isomerization of n-hexane, n-heptane and n-octane to their corresponding branched isomers. The best performing catalyst (SZS-2) was characterized by TEM, SEM, AFM, FTIR, TG-DTA, BET and small angle XRD. The super acidity of the catalyst was measured by performing ammonia-TPD. From this end, the SZS-2 contains nano particles of ~ 20 nm, presenting an amorphous nature and having no definite surface morphology.  Catalyst evaluation and characterization allowed proposing a reaction mechanism, elucidating a probable role of Bronsted and Lewis acid sites on the studied reaction-catalyst. This catalyst can be effectively used in future to enhance the efficiency of petroleum.