Pd–Pt promoted HPMo/UiO-66 acid catalyst for n-hexane hydroisomerization for higher quality and cleaner fuel production: Catalytic activity and kinetic modeling

Abstract

The preparation of catalysts with adequate stability for the n-hexane hydroisomerization reaction is always a challenge in refineries. Therefore, in this work, the metal-organic framework UiO-66, heteropoly phosphomolybdic acid (HPMo), and bifunctional (Pd + Pt)/HPMo/UiO-66 samples were synthesized, characterized by experimental techniques, and tested in the n-hexane hydroisomerization reaction. As a result, the microporous (0.2%Pd+0.3%Pt)/30%HPMo/UiO-66 bifunctional catalyst exhibited an iso-hexane selectivity of 86% and n-hexane conversion of 72.1% after 36 h of reaction time. In addition, the Langmuir-Hinshelwood model was used to examine the kinetics of this reaction due to the inhibitory effect of hydrogen. The results provided an acceptable fit to the experimental data and allowed the determination of the kinetic parameters. Accordingly, the apparent activation energy of this bifunctional catalyst and the adsorption heats of hydrogen and n-hexane were calculated at 26.27, −16.12, and −7.82 kJ mol−1, respectively.