活性炭负载铑基催化剂的制备条件研究

Preparation conditions of activated carbon-supported rhodium-based catalyst

为研制高碳醛合成用易分离催化剂,文中以RhCl3为前体,以活性炭为载体,采用等体积浸渍法制备了负载铑基催化剂。使用N2吸附-脱附和Boehm滴定对不同载体进行了表征,考察了载体预处理和制备条件对催化剂活性的影响。结果表明,经过高温热处理的活性炭载体比表面积和孔容略有降低,中孔分布变窄,表面含氧基团大大增加,从而使催化剂氢甲酰化性能得到提高。合适的铑负载质量分数为0.6%—1.0%,磷酸负载质量数为5.0%。焙烧温度低于400℃时,对催化剂性能影响不大。

Aimed at based catalyst was p developing an easily-separated catalyst to synthesize higher aldehydes, a supported rhodium- repared by incipient impregnation with RhCl3 as precursor and activated carbon as support. N2 adsorption - desorption and Boehm titration were used to characterize the different supports. The effects of support pretreatment and preparation conditions on catalytic activity were studied. The results show that the specific surface area and pore volume of activated carbons decrease slightly, the mesopore size distribution becomes narrow, and the surface oxygen-containing groups increase markedly after heat treatment at high temperature. These changes cause an increase in the catalytic performance for hydroformylation. The suitable loading （ mass fraction） of rhodium and phosphoric acid are 0.6% -1.0% and 5.0%, respectively. Calcination temperature has little effect on properties of catalyst below 400℃.