Sulphated mesoporous La2O3–ZrO2 composite oxide as an efficient and reusable solid acid catalyst for alkenylation of aromatics with phenylacetylene

• SO42−/meso-La2O3–ZrO2 is an efficient solid acid catalyst for direct alkenylation.
• Developed catalyst shows high selectivity and easily regeneration behavior.
• La incorporation into ZrO2 significantly improves catalytic performance.
• Catalytic property strongly depends on catalyst nature affected by La addition.
• This work presents a robust catalyst for producing α-arylstyrenes via alkenylation.

Sulphated mesoporous La2O3–ZrO2 composite oxides (SO42−/meso-La2O3–ZrO2) were firstly prepared by a surfactant-assisted co-precipitation/hydrothermal crystallization with subsequent impregnation method (SACPHC-IM). The prepared SO42−/meso-La2O3–ZrO2 catalyst was employed as solid acid to catalyze direct alkenylation of p-xylene with phenylacetylene for clean production of α-arylstyrene. Various characterization techniques such as N2 adsorption–desorption, X-ray diffraction (XRD), FT-IR, NH3 temperature-programmed desorption (NH3-TPD), and pyridine-IR were employed to reveal the relationship between catalyst nature and catalytic performance. The as-prepared SO42−/meso-La2O3–ZrO2 catalyst shows much superior catalytic activity and similar selectivity to SO42−/meso-ZrO2, ascribed to increasing acid properties, enlarging specific surface area and increasing pore volume, reducing average crystalline size resulting from the promoting effect of adding La into ZrO2 matrix. Furthermore, the SO42−/meso-La2O3–ZrO2 catalysts were optimized by varying the atomic ratio of La/(La + Zr) from 0.05 to 0.2. The SO42−/meso-La2O3–ZrO2 catalyst with the 0.1 of optimum La/(La + Zr) atomic ratio exhibited excellent catalytic performance, ascribed to the increase in amount acid sites and pore size. The results for stability test demonstrated that close to 100% of maximum conversion can be achieved, and more than 80% of conversion can be maintained with the time on stream up to 780 min. Through simple calcination treatment, the spent catalyst can be almost complete recovered. The developed SO42−/meso-La2O3–ZrO2 catalyst could be a potential candidate for α-arylstyrene production via acid catalyzed direct alkenylation of aromatics with phenylacetylene.

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