Study On The Kinetics Of P-Xylene Liquid Air Oxidation

Purified terephthalic acid (PTA) is the important feedstock in production of polyester. Usually in the first step of the process, crude terephthalic acid (CTA) is obtained via catalytic oxidation of liquid p-xylene with air at high temperature in acetic acid solvent. And then CTA is purified by hydrogenation. This paper focuses attention on the research and analysis of the oxidation of p-xylene (PX).Firstly, a special and novel experimental device for PX oxidation reaction was designed and developed. And several methods were used to settle the temperature control and sampling. And the solid sample and liquid sample can be separated quickly, and the real concentration of components in the liquid and solid can be detected. The anlysis methods for compeonts in the PX oxidation procees was developed, this method is rapidly and exactly.and this method is a base for get the veracious kinetics data.Secondly, factors that influence the reaction was invesrigated and the factors included reaction temperature and initial concenreation of PX. Experiments results shown that the concentration of 4-CBA in the solid was not decreased in the reaction process. And the concentration was linearity with the initial concentration of PX. The hyperbolic kincetics model was used to fit the experiment data, and the concentration of 4-CBA in the liquid and solid was related in the model. The reaction kinetics equation and the reaction activity energy were obtsained by caluculation. On the base of kinetics data, a mathematic model of PX oxidation reactor was developed, with which the industrial reaction condition was simuliated, and calculated results were coincident with industrial prodess data.