钯催化膜上对硝基苯酚加氢本征动力学  

Intrinsic Kinetics of Hydrogenation of p-nitrophenol over Palladium Catalytic Membrane

作　　者：李汉阳[1,2] 孙晓旭[1,2] 姜红[1,2] 陈日志[1,2] 

机构地区：[1]南京工业大学材料化学工程国家重点实验室,江苏南京210009 [2]南京工业大学江苏省工业节水减排重点实验室,江苏南京210009

出　　处：《化学反应工程与工艺》2013年第6期535-541,共7页Chemical Reaction Engineering and Technology

基　　金：国家自然科学基金(21106061);国家科技支撑计划(2011BAEO7B05)

摘　　要：采用强制对流方法将纳米钯颗粒负载于陶瓷膜上制备钯催化膜,研究了钯催化膜上对硝基苯酚加氢本征动力学。考察了蠕动泵转速、对硝基苯酚浓度、硼氢化钠浓度和反应温度等因素对对硝基苯酚初始反应速率的影响,并采用幂函数方程对实验数据进行拟合。结果表明:当蠕动泵转速大于50 r/min时,外扩散影响基本消除,催化膜中钯颗粒的粒径约为5 nm,其内扩散影响可以忽略,反应进入动力学控制区;反应对于对硝基苯酚、硼氢化钠的反应级数分别为0和0.75,反应活化能为8.45 kJ/mol,反应指前因子为4.25 mmol0.25/(L0.25·min)。依据上述结果建立了反应本征动力学方程,并对模型进行验证,结果显示对硝基苯酚初始反应速率的模型计算与实验值吻合较好,其平均相对偏差约为5%。The palladium catalytic membrane was prepared by the flow-through method with the palladium nanoparticles immobilized on the ceramic membrane. The intrinsic kinetics of catalytic hydrogenation of p-nitrophenol over the palladium catalytic membrane was studied. The effects of rotation rate of peristaltic pump, p-nitrophenol concentration, sodium borohydride concentration and temperature on the initial reaction rate ofp-nitrophenol were investigated, and a power function equation was used to fit the data. When the rotation rate was over 50 r/min, the effect of external diffusion could be ignored. The particle size of palladium in the as-prepared palladium catalytic membrane was about 5 nm and the effect of internal diffusion could be ignored. As a result, the reaction was controlled by the kinetics. The orders of the reaction were found to be 0 for p-nitrophenol and 0.75 for sodium borohydride, respectively. The reaction activation energy was 8.45 kJ/mol and the pre-exponential factor was 4.24 mmol^0.25/（L^0.25·min）. According to the above works, the intrinsic kinetic model was established. The calculated initial reaction rates ofp-nitrophenol were in good agreement with the experimental results, and the average relative error was 5 %. This study would provide the fundamental data for development of palladium catalytic membrane and membrane reactor.

关 键 词：钯 陶瓷膜 催化膜 对硝基苯酚 本征动力学 

分 类 号：O643.12[理学—物理化学] TQ032.4[理学—化学]