A single-step catalytic process for the production of high-octane molecules from normal paraffins using zeolite supported bi-functional catalysts

Stringent fuel specifications qualify no single refinery stream to work alone as gasoline fuel and reformulated gasoline blends various refinery streams appropriately to meet the desired fuel specifications. Branched paraffins, generally called isomerate, along with toluene and xylenes belonging to aromatics, are the desired components in gasoline. Benzene minimization is desired due to carcinogenicity considerations. Through existing conventional processes, the formation of these various components is thermodynamically favored under different sets of reaction conditions (lower reaction temperature favors branched paraffin while higher reaction temperature favors aromatics). Here we report a single-step process that works on a single catalyst system to produce low-benzene, toluene-and-xylene-rich, branched paraffin (isomerate)-rich and high-octane gasoline product from n-heptane. Several ZSM-5 zeolites varying in framework Si/Al ratio have been studied to select the proper acidity, followed by metal functionalization with Pt and, or Co to facilitate the branching and dehydrocyclization reactions of n-heptane in a vapor-phase continuous-flow operation in the presence of N2 as carrier gas. Detailed reaction studies indicated exciting findings related to co-formation of iso-heptanes and aromatics through a common cyclic intermediate in a single step process; thus, provides a path from linear alkanes to a promising gasoline stock for fuel applications.