Fluoride-treated IM-5 zeolite as a highly active catalyst for the production of jet fuels by the oligomerization of 1-hexene

Abstract

Light alkenes oligomerization, performed in the presence of solid acid catalysts, is an important alternative for the production of clean jet fuels. For 1-hexene oligomerization, the current catalyst often suffers from low activity and selectivity. The developed process is upgraded by zeolite catalyst, targeting high-concentration of jet-range hydrocarbons. An efficient and selective IM-5 zeolite-derived catalytic system has been developed for the oligomerization of 1-hexene. The treatment in an aqueous NH4F solution led to dealumination without structure degradation. The IM-5 zeolite with a unique two-dimensional IMF structure and 2.5 nm nanoslab showed rapid diffusion ability than ZSM-5 zeolite. Enhance acidities were observed in the NH4F-treated IM-5 zeolites owing to fluoride residue and the removal of Al atoms. The strong Brønsted acid sites exerted a positive effect on both the cracking and the oligomerization reactions with the increasing of the yields of dimers. The contact time and partial pressure between the 1-hexene and the IM-5 zeolites were used to analyze the competition of cracking reactions. High 1-hexene conversion (62%), optimal oligomerization to C3-C5 ratio (O/C = 32), and reasonable stability were obtained over the etched IM-5 catalyst at 240 °C, 4 MPa, and the flow rate of N2 was 50 mL/min.