四苯基锌卟啉催化氧气氧化对硝基乙苯的表观动力学研究

本文在研究氧气氧化对硝基乙苯反应时，发现双-(α-甲基-4-硝基苄基)过氧化物为关键中间产物，对硝基苯乙酮为主产物，在此基础上建立了四苯基锌卟啉（TPPZn）催化氧气氧化对硝基乙苯的反应模型和速率方程，对其表观动力学行为进行了深入的研究。同时，根据110-150℃范围内所测得的实验数据，计算出了相应的反应速率常数，确立了对硝基乙苯氧化生成双-(α-甲基-4-硝基苄基)过氧化物的第一步为零级反应，表观活化能为39.5kJ/mol；双-(α-甲基-4-硝基苄基)过氧化物分解生成对硝基苯乙酮的第二步反应为1/2级反应，表观活化能为44.6kJ/mol。对比同一温度下的反应速率常数k1和k2，发现低温时k2和k1基本相等，而高温时k2大于k1。通过比较两步反应的表观活化能和反应速率常数，发现升高反应温度有利于对硝基苯乙酮的生成，且可以提高其生成速率。

Apparent Kinetics Study on the Oxidation of p-Nitroethylbenzene Catalyzed by Zinc Tetraphenylporphyrin

In the aerobic oxidation of p-nitroethylbenzene,it is found that bis(α-methyl-4-nitrobenzyl) peroxide as the key intermediate and p-nitroacetophenone as the main products.So the apparent kinetics was investigated in depth though the establishment of reaction model and rate equation of the oxidation of p-nitroethylbenzene catalyzed by zinc tetraphenylporphyrin(TPPZn) that base on the above compounds.Meanwhile,the apparent rate constants of two reactions were calculated according to the experimental data in the temperature range(110—150)℃.The results showed that the first step of oxidation of p-nitroethylbenzene to bis(α-methyl-4-nitrobenzyl) peroxide was a zero-order reaction with the apparent activation energy of 39.5 kJ/mol,and the second step of decomposition of bis(α-methyl-4-nitrobenzyl) peroxide to p-nitroacetophenone was a half-order reaction with the apparent activation energy of 44.6 kJ/mol.Comparing with the apparent rate constants k1 and k2 under same temperature,it was found that the k2 approximate equal to k1 at low temperatures,and the k2 greater then k1 at high temperatures.So,increasing temperature was favorable for the formation of p-nitroacetophenone and with a faster reaction rate by comparing apparent activation energies and reaction rate constants of two step reactions.