Pd-AlCl_3-凹土催化剂催化苯酚选择性加氢制环己酮

On Pd-AlCl_3-Palygorskite Composite Catalyst Catalyzing Selective Hydrogenation of Phenol to Make Cyclohexanone

以凹凸棒石黏土为载体,采用浸渍还原和回流吸附负载Pd和AlCl3制备Pd-AlCl3-PAL加氢催化剂,并用于苯酚选择性加氢制环己酮。采用XRD、EDX、TEM对催化剂进行了表征,考察AlCl3、Pd含量以及反应时间和温度对苯酚加氢制环己酮的影响。结果表明:AlCl3的引入和Pd含量的增加可增加催化剂的活性,提高产物环己酮选择性。反应温度的提高可能导致溶剂挥发带走苯酚,其苯酚转化率下降。反应时间的延长并没有显著提高苯酚转化率,反而产生环己醇使环己酮选择性下降。适宜的反应条件为Pd含量5%,反应温度50℃,反应时间1.5h,此时催化剂活性最好,苯酚转化率为98.45%,环己酮选择性可达到94.77%。

Pd - AlCl3 - PAL composite hydrogenation catalyst was prepared by impregnation - reduction and reflux adsorption using palygorskite as supporter which was used for hydrogenation of phenol to make cyclohexane. The catalyst was characterized by X - ray diffraction, energy dispersive X - ray spectroscopy, and transmission electron microscopy, respectively. The effects of AlCl3 ,Pd content, reaction temperature and time on the catalytic properties of the catalyst were also investigated. The results indicated that the introduction of AlCl3 and increase of Pd content could increase the catalytic activity of catalyst and selectivity for cyclohexanone. The increase of reaction temperature reduced the phenol conversion for the decrease of phenol with evaporation of solvent. The prolong reaction time could not significantly increase phenol conversion which Instead decreases the selectivity of cyclohexanone and produces cyclohexanol. The appropriate reaction condition is： the Pd content of 5%, the reaction temperature of 50℃, and the reaction time of 1.5h, the conversion of phenol of 98.45%, and the selectivity of cyclohexanone reaching 94.77%.