载体预处理对苯酚加氢制环己酮用催化剂的影响

Effect of Support Pretreatment on Catalyst for Hydrogenation of Phenol to Cyclohexanone

采用不同试剂改性活性炭,制备苯酚加氢制环己酮用催化剂。对改性后活性炭的比表面积、孔容、孔径物理性质和钯炭催化剂进行表征,探究不同试剂预处理对活性炭及钯炭催化剂的影响。结果表明:氧化预处理使活性炭的比表面积和孔容下降,使钯炭催化剂上的钯粒子尺寸相对更小;碱预处理有一定的扩孔作用,使钯炭催化剂上的钯粒子尺寸更大;酸处理会增大活性炭的比表面积、孔容、孔径,同时会提高苯酚加氢反应中环己酮的选择性;HNO3处理的活性炭制备的催化剂在苯酚加氢反应中,苯酚转化率和环己酮选择性最高。

Different reagents were used to modify activated carbon to prepare catalysts for hydrogenation of phenol to cyclohexanone.The specific surface area,pore volume,pore size and physical properties of the modified activated carbon and the palladium-carbon catalyst were characterized.The results showed that the specific surface area and pore volume of the activated carbon by oxidative pretreatment decreased,and the palladium particles of Pd/C catalyst were relatively small.The alkali treatment had a certain effect of enlarging pore,and Pd/C catalyst had larger Pd particles.Acid treatment increased the specific surface area,pore volume and pore diameter of activated carbon,and improved the selectivity of cyclohexanone in phenol hydrogenation.In the hydrogenation of phenol over HNO3-treated activated carbon,the conversion of phenol and the selectivity of cyclohexanone were the highest.