Highly selective catalysis for hydroisomerization of isobutane to n-butane at elevated temperature: Thermodynamic feasibility analysis

To address insufficient n -butane from conventional separation methods, this study investigates the hydroisomerization of isobutane through experiments and thermodynamic analysis, focusing on suppressing isobutene formation to below the industrial threshold of 0.1 %. The Pt/ZSM-22 catalyst exhibited excellent selectivity within the temperature range of 375–485 °C in a 16-channel fixed-bed reactor. Thermodynamic analysis (50–650 °C) confirmed the endothermic nature of the primary reaction and accurately predicted the temperature-dependent variation of isobutene concentration, showing strong agreement with experimental results. The derived optimal conditions (250–450 °C, 3.0 MPa, H 2 /hydrocarbon = 0.5–1.0) ensured the mass fraction of isobutene in products remained less than 0.1 %, providing valuable guidance for industrial process optimization. • Currently, isobutane isomerization reaction is usually catalyzed by Pt supported catalyst with strong acid cite as carriers such as chlorinated alumina (Al 2 O 3 -Cl) or sulphated zirconia (SO 4 2− /ZrO 2 ). But the catalysts can only be used at the temperature lower than 250 °C, which is thermodynamically unfavorable for isobutane isomerization. The development of highly efficient and selective catalysts for isobutane isomerization reaction at high temperature is a challenge in catalysis. • In this communication, we report the hydroisomerization of isobutane to n -butane at the temperature as high as 435 °C over a ‌Pt/ZSM-22 zeolite catalyst, with selectivity to n -butane of 87.91 % at a 45.76 % conversion of isobutane. • Moreover, thermodynamic analysis‌, ‌using simplified reaction schemes‌, ‌enables to optimize the reaction conditions of isobutane isomerization reaction and quantify‌ the concentration of the ‌byproduct isobutene accurately.