Carbonylation of ethanol using homogeneous rhodium complex catalysts is an essential route for the manufacture of propionic acid, as carbonylation of methanol to acetic acid is a large‐scale commercial process that could provide critical insights for the ethanol carbonylation process. The reaction mechanism of ethanol has not been well understood yet, and the high cost of downstream separation due to high water content is still worrying. Consequently, propionic acid was used as solvent to reduce water content in the kinetic experiments carried out in a semibatch autoclave reactor. Homogeneous rhodium was used as complex catalyst with HI as a promoter and propionic acid as solvent. The effects of ethanol, hydroiodic acid, rhodium, and the pressure of carbon monoxide on reaction rate and selectivity of propionic acid were investigated. The reaction mechanism was determined through these batches in the meantime. A kinetic model for ethanol carbonylation was deduced based upon the observations and reaction mechanism. The parameters of the model were regressed and verified with the experimental data. The activation energy was found to be 75.6 kJ·mol⁻¹. Residual error distribution and a statistical test showed that the kinetic model is reasonable and acceptable.

中文翻译：

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均相Rh络合物催化剂催化乙醇羰基化反应的动力学研究。

使用均相铑配合物催化剂将乙醇羰基化是制造丙酸的必经之路，因为甲醇羰基化为乙酸是大规模的商业流程，可为乙醇羰基化过程提供重要见解。乙醇的反应机理尚未被很好地理解，并且由于高水含量而导致的下游分离的高成本仍然令人担忧。因此，在半间歇式高压釜反应器中进行的动力学实验中，丙酸用作溶剂以减少水含量。均相铑用作配合物催化剂，HI为促进剂，丙酸为溶剂。研究了乙醇，氢碘酸，铑和一氧化碳的压力对丙酸反应速率和选择性的影响。同时通过这些批次确定了反应机理。根据观察结果和反应机理，推导了乙醇羰基化反应动力学模型。对模型参数进行回归，并与实验数据进行验证。发现活化能为75.6 kJ·mol^-1。残差分布和统计检验表明该动力学模型是合理且可以接受的。