钾掺杂的锐钛矿TiO_(2)催化丙酸酮基化反应

Ketonization of propionic acid on potassium-doped anatase TiO_(2) catalysts

酮基化反应是转化生物质衍生羧酸的有效途径之一。为了提高酮基化反应活性和选择性,使用等体积浸渍法制备了不同钾(K)掺杂量的TiO_(2)催化剂,并探究其催化丙酸酮基化反应性能。通过X-射线粉末衍射、透射电子显微镜和X-射线光电子能谱等方法对催化剂的物化性质进行表征。结果表明,TiO_(2)、0.05K(掺杂K的质量分数为5%)催化剂的本征反应速率分别为549.2μmol·g^(-1)·min^(-1)、2 686.2μmol·g^(-1)·min^(-1),K的掺杂显著提高了反应活性,并且在丙酸完全转化时,0.05K催化剂的3-戊酮选择性(99.9%)高于TiO_(2)催化剂(96.2%)。根据X射线光电子能谱的表征,TiO_(2)和钾氧化物之间存在明显的相互作用,促进了表面氧空位的生成从而提高反应活性。

Ketonization reaction is one of the effective approaches for converting biomass derived carboxylic acids.To improve the activity and selectivity of ketonization,TiO_(2) catalysts with different K doping amounts were prepared using an incipient wetness impregnation method and their catalytic performance for ketonization of propionic acid was studied.The physicochemical properties of the catalysts were characterized by X-ray powder diffraction(XRD),transmission electron microscopy(TEM)and X-ray photoemission spectroscopy(XPS).The results showed that the intrinsic ketonization reaction rates of TiO_(2) and 0.05K(with 5%K doping on TiO_(2))catalysts were 549.2 and 2686.2μmol·g^(-1)·min^(-1),respectively,indicating that doping K significantly improved the activity of TiO_(2).Moreover,the selectivity of 3-pentanone on the 0.05K catalyst(99.9%)was higher than that on TiO_(2)(96.2%)when propionic acid was completely converted.Based on XPS results,there is a significant interaction between TiO_(2) and potassium oxide,which promotes the formation of surface oxygen vacancies and thus enhances the activity.