摘要
The highly selective catalytic transfer hydrogenation(CTH)of furfural(FF)to furfuryl alcohol(FOL)is a significant route of biomass valorization.Herein,a series microporous Zr-metal organic framework(ZrMOF)functionalized by sulfonic groups are prepared.Based on the comprehensive structural characterizations by means of X-ray diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM),N2 physisorption,Thermogravimetric(TG)and Fourier transformed infrared spectroscopy(FTIR),we find that sulfonic acid(–SO_(3)H)functional groups are tethered on the UIO-66 without affecting the structure of the framework.Systematic characterizations(NH_(3)-TPD,CO_(2)-TPD,and in-situ FTIR)demonstrate that modifying of sulfonic groups on UIO-66 results in the formation of stronger Lewis acidic-basic and Brnsted acidis sites.The cooperative role of the versatile Lewis acidic-basic and Brnsted acidic sites in 60%mol fraction of sulfonic acid-containing UIO-66(UIO-S_(0.6))retain high surface area and exhibit excellent catalytic performance of 94.7%FOL yield and 16.9 h^(-1).turnover number(TOF)under mild conditions.Kinetic experiments reveal that the activation energy of the CTH of furfural(FF)over UIO-S_(0.6) catalyst is as low as 50.8 k J mol^(-1).Besides,the hydrogen transfer mechanism is investigated through isotope labeling experiments,exhibiting that theβ-H in isopropanol is transferred to the a-C of FF by forming six-membered intermediates on the Lewis acidic-basic and Brnsted acidic sites of the UIO-S_(0.6),which is the rate-determining step in the formation of FOL.
基金
supported by the National Key R&D Program of China(2020YFA0710000)
the National Natural Science Foundation of China(22122901,21902047)
the Provincial Natural Science Foundation of Hunan(2020JJ5045,2021JJ20024,2021RC3054)
the Shenzhen Science and Technology Program(JCYJ20210324140610028)。
