Effective Catalyst for Removing Trace Olefins from Reforming Aromatics: Sulfated Zirconia with High Sulfur Content Synthesized by Sulfonation with Chlorosulfonic Acid

Sulfated zirconia was synthesized adopting chlorosulfonic acid as a novel sulfonating reagent, with significantly improved sulfur content and less sulfur leaching than conventional sulfated zirconia. The optimized sulfonation process, guided by the incipient-wetness impregnation method, reduced the waste of energy and environmental pollution caused by the excess acid solution to a certain extent. The catalysts were characterized using EA, TGA, FTIR, XPS, XRD, FE-SEM, HR-TEM, N2adsorption-desorption isotherms, and pyridine-adsorbed Fourier transform infrared spectroscopy (Py-FTIR) techniques to investigate the effect of synthesis variables on the physicochemical properties of the catalysts in detail. Further, the catalytic performance of these catalysts in alkylation for removing trace olefins from aromatics was systematically evaluated using a continuous-flow fixed-bed tubular microreactor. It was evident from the results that the synthesis variables, such as the concentration of chlorosulfonic acid, sulfonation time, and calcination temperature, were significant factors affecting the surface sulfur species and structural, textural, acidic properties as well as catalytic properties of the as-synthesized catalysts. The CSZ650-(0.75, 5) catalyst, synthesized by sulfonation with 0.75 M chlorosulfonic acid for 5 min and by air calcination at 650 °C, exhibited more outstanding catalytic performance than various other typical heterogeneous catalysts, such as sulfated zirconia synthesized by sulfuric acid, zeolites, and acid clay. The negligible decrease in catalytic activity over four catalytic runs revealed the excellent reusability of the CSZ650-(0.75, 5) catalyst, making the catalyst promising for industrial applications. © 2022 American Chemical Society. All rights reserved.