锆铪催化添加剂对PX液相氧化过程的影响

Effect of Zr and Hf Additives on p-Xylene Liquid Phase Oxidation

向对二甲苯(PX)催化氧化体系加入锆铪离子可有效地加速该反应过程.对锆铪离子与Co-Mn-Br催化剂体系的协同催化机理作了简要阐述,并对添加不同浓度下锆铪离子的催化作用进行了动力学实验,考察了添加锆和铪离子对主反应和燃烧副反应的影响,获得了锆铪离子添加剂对PX氧化过程的影响规律.研究发现,在实验所考察的温度与催化剂组成条件下,添加锆铪离子对反应过程中不同阶段的加速效果各不相同,且两种离子对燃烧副反应过程也有不同程度的加速作用.

p-Xylene liquid phase oxidation would be accelerated by the addition of zirconium or hafnium ions to the Co/Mn/Br catalyst system. In this paper, the activating catalysis mechanisms of Zr and Hf promoters were presented concisely, and a series of PX oxidation experiments at different Zr and Hf concentrations were carried out. A well-known kinetic model was employed to fit the data and the rate constant for each oxidation step was obtained. The rate constant data show that the effect of Zr and Hf additives on the reaction rate of different stages of PX oxidation is various, and hafnium is more active than zirconium. In the other hand, CO_X productions data illustrate that the burning rate increase with adding Zr and Hf in a different extent.