Fe-ZSM-5分子筛催化剂上N_2O一步氧化苯制苯酚的积炭动力学

Kinetics of Coke Formation on a Fe-ZSM-5 Zeolite Catalyst in the One-Step Oxidation of Benzene to Phenol with N_2O

采用等温固定床反应器和热重分析相结合的方法研究了Fe-ZSM-5分子筛上N2O一步氧化苯制苯酚的积炭行为,考察了反应时间、温度和原料配比对积炭量的影响.依据实验现象和积炭物组分分布的气相色谱-质谱分析结果,提出了Fe-ZSM-5分子筛上N2O一步氧化苯制苯酚的积炭机理.结果表明,Fe-ZSM-5分子筛上的积炭物种主要来源于氧化产物苯酚的深度氧化,属连串失活.基于所提出的积炭机理和实验结果,建立了Fe-ZSM-5分子筛催化剂的积炭动力学模型,统计检验和残差分布检验表明,所建模型与实验结果相容,可靠性强.

The coking behavior of the Fe-ZSM-5 zeolite catalyst during the oxidation of benzene to phenol with N2O was studied in an isothermal fixed-bed reactor using thermogravimetry.The effect of reaction time and temperature as well as the molar ratio of reactants on coking was investigated.Based on the information obtained from experiments and gas chromatography-mass spectrometry analysis of the coke on the catalyst,we suggested a mechanism for coke formation.The results showed that the formed coke mainly from the further oxidation of phenol,revealing that sequential deactivation occurred in the main reaction.Based on the suggested mechanism,a kinetic model for coke formation that describes coke deposition on the Fe-ZSM-5 zeolite catalyst was developed.A statistical test and a residual distribution analysis showed that the kinetic model established here was in good agreement with the experimental data and was acceptable and reliable.