Fabrication of heterogeneous tannic acid-zirconium mesoporous material and the catalytic performance on cycloaddition of CO2 with epoxide
The cycloaddition of CO2 with epoxide is an effective and sustainable strategy for the chemical conversion of CO2,and its product,cyclic carbonate,is applied widely in the fields of lithium-ion batteries and polymer materials.For the cycloaddition of CO2 with epoxide,it is crucial to construct catalysts with efficient epoxide adsorption activation sites since the ring-opening of the epoxide is deemed to be the key step.In this paper,TA-Zr-2,a non-homogeneous tannic acid-zirconium mesoporous material containing both Lewis acid site of zirconium metal center and hydrogen-bonding site of phenolic hydroxyl,was prepared via the coordination of tannic acid and zirconium ions.XPS and epichlorohydrin TPD-MS results showed that the zirconium metal center of TA-Zr-2 had stronger Lewis acidity and adsorption activation to epoxypropane compared to UiO-66 which was also a zirconium-based porous material.The TA-Zr-2-FD catalyst was obtained by freeze-drying treatment on basis of TA-Zr-2,and the catalytic performance was improved 1 times to TA-Zr-2 with 97.6%yield of butylene carbonate due to the larger specific surface area and suitable pore volume.In summary,a tannic acid-zirconium mesoporous material with large specific surface area was constructed by using a simple and green preparation method.The synergy of zirconium Lewis acid site and phenol hydroxyl hydrogen-bonding was beneficial to the adsorption and activation of epoxide,thus facilitating the epoxide ring-opening and enabling the catalyst to exhibit good catalytic performance for cycloaddition of CO2 with epoxide at 25℃.
CO2 conversioncycloaddition reactioncyclic carbonatemesoporous material
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