We report the role of hydrogen spillover in n-hexane isomerisation over carbon nanotubes or SiC mixed with hierarchical zeolite beta. Here we infer that: (1) hydrogen spillover is a necessary step; (2) spilled-over H hydrogenates isomerised olefin at Brønsted acid sites only; and (3) closeness between acid and metal sites at the nanoscale enhances the rate of reaction, though this is not a requirement for this reaction to proceed. The economic advantage of the spillover phenomenon (necessitating less Pt on the catalyst) has been highlighted.

The present work deals with isomerization of straight chain paraffin, n-hexane with an aim to make up loss in gasoline quantity as well as octane. This is due to its reduced benzene content warranted by its carcinogenic nature. Performance of impregnation of alkaline earth metals (Mg, Ca, Sr, and Ba) on Pt/desilicated (and dealuminated) zeolites Beta was studied and found that isomer selectivity as high as 99% with stable catalytic performance is achievable. Furthermore, replacing part of hydrogen (15%) with carbon dioxide in hydrogen as carrier gas improves hexane conversion. Hexane conversion increased as Mg-< Ba-< Ca-< Sr-Pt/deSi Beta. Observed performance parameters have been explained on the basis of reported variation in acidity due to both alkaline earth metals and CO 2 .