The Research On Preparation Of Terepthalic Acid Via Aerobic Oxidation Of P-Xylene Catalyzed By (T_p-ClPPFe)₂O/Co(OAc)₂

The liquid-phase catalytic oxidation of p-xylene by molecular oxygen is an important reaction for the production of commodity chemicals.The terephathlic acid(TA), one of the oxidate product of p-xylene, is an important polyester raw materials.TA has extensive industrial application, such as Polyester resin, polyester fibers, films, insulating paint, engineering plastics, plasticizers, fuel intermediates, polyester chip, poultry feed additive. TA is an important industrial chemicals. In recent years, with polyester bottles and film demand growth.The demond of TA greatly promoted the production of TA.At present, the traditional p-xylene catalytic oxidation for preparing the p-TA and the TA, confined by the environment and energy crisis , badly in need of reform. The requirements of developing green oxidant catalyst system replace the existing production process is increasingly urgent.To investigate the selective aerobic oxidation of p-xylene to terephthalic acid, the simple metalloporphyrins/cobalt acetate complex catalyst are introduced to catalyze p-xylene under various conditions in the absence of any solvent, by using orthogonal designation method, we obtained the optimized condition of aerobic oxidation of p-xylene.The contents of this paper are presented as follows:1. Under the condition of no-solvent, metalloporphyrins/cobalt acetate as the complex catalyst, we studied the aerobic oxidation of p-xylene system.Inspected the rule of catalyst composition, metalloporphyrin concentration, cobalt salt concentration, as well as tempreture and pressure affect on the oxidation of p-xylene.2. Base on the technic parameter single-factor analysis, we confirmed the optimized conditions: metalloporphyrin concentration,the rate of metalloporphyrins/cobalt acetate, air pressure, tempreture, time, air flow rate.And achieve the reasonable technic parameter scale .3. By using the orthogonal designation method, the oxidation system was optimized, and analysized the results using the range analysis.We achieve the optimized condition: metalloporphyrin concentration is 4 ppm, the rate of metalloporphyrins/cobalt acetate is 60, the air pressure is 0.8 MPa, the tempreture is 180℃, the reaction time is 4.5h, air flow rate is 200 L·h-1.4. Certification test:under the optimized conditions we achieved, we gained the optimized result: the conversion of p-xylene is about 65%, the selectivity of TA is about 13%.It's higher than the results in the orthogonal table.The cetification test proved that the optimized condition we achieved is correctly.5. A new method of preparing tetraphthalic acid was brought forward., avoid the traditional method of high-corrosive acetic acid solvent.