Abstract

Three reaction-diffusion kinetic models were developed to explain the kinetics and the mass transfer of the esterification of acetic acid with isopropanol, over niobium pentoxide. The kinetic equations were defined by the pseudo-homogeneous, Eley-Rideal and Langmuir-Hinshelwood-Hougen-Watson models. Firstly, the effect of Nb₂O₅ calcination temperature was evaluated. Later, the effects of reaction temperature, stirring speed and catalyst loading on the reaction conversion were also evaluated. Method of lines was applied to solve the partial differential equations of the models. The kinetic parameters were estimated using a hybrid combination of particle swarm optimization and non-linear least squares algorithm. The performance of the models was evaluated by statistical metrics and Fisher’s test. Reaction tests showed that conversion increased at higher temperature and catalyst loading, however, it remained constant with increasing stirring speed. The conversion increased by around six times when the temperature was raised from 60 to 90 °C. An increase of 7.27% in the conversion was seen when increasing the catalyst loading from 5 to 6 g. Despite the very good models’ prediction, the reaction-diffusion model with LHHW kinetics was the more accurate to predict the heterogeneous esterification of acetic acid with isopropanol over niobium pentoxide according to the statistical analysis.

摘要

开发了三个反应扩散动力学模型来解释乙酸与异丙醇在五氧化二铌上的酯化反应的动力学和传质。动力学方程由伪均质、Eley-Rideal 和 Langmuir-Hinshelwood-Hougen-Watson 模型定义。一、Nb ₂ O _5的作用评估煅烧温度。随后，还评估了反应温度、搅拌速度和催化剂负载量对反应转化率的影响。应用直线法求解模型的偏微分方程。使用粒子群优化和非线性最小二乘算法的混合组合来估计动力学参数。模型的性能通过统计指标和 Fisher 检验进行评估。反应测试表明，转化率在较高温度和催化剂负载量下增加，然而，随着搅拌速度的增加，转化率保持不变。当温度从 60 °C 升高到 90 °C 时，转化率增加了大约六倍。当催化剂负载量从 5 克增加到 6 克时，转化率增加了 7.27%。