Removal of Olefins from Reforming Aromatic Hydrocarbonsover Metal-Halide-Modified Acid-Activated Palygorskite

A series of acid-activated palygorskite (PAL)-supported metal halides catalysts were synthesized and applied to remove trace olefins from aromatic hydrocarbons. The structural properties and surface acidity of acid-activated PAL were determined by X-ray diffraction (XRD), N2 adsorption/desorption, and NH3-TPD. According to experimental results, the optimum metal halide was CoCl2, and its loading content was 7 wt % with an olefin conversion of 92.1%. Furthermore, the 10%CoCl2/PAL-B21 catalyst before and after the olefin removal reaction was characterized by XRD, FE-SEM, FTIR, N2 adsorption/desorption, NH3-TPD, and XPS. The BET surface area (SBET) of PAL-B21 decreased by 129 m2/g after modification by 10%CoCl2. It was indicated that the interaction between CoCl2 and PAL-B21, the textural properties, and the surface acid sites are all important for the adsorption and conversion of olefins from reforming aromatic hydrocarbons by an alkylation reaction. The low cost, high olefin conversion, and good stability of the CoCl2-modified PAL-B21 catalyst provide industrial application potential for olefin removal from reforming aromatic hydrocarbons.