Determination of the kinetics and mechanism of methyl formate synthesis in the presence of a homogeneous catalyst

The kinetics and mechanism of methyl formate synthesis, the key intermediate of the formic acid process was determined. Methyl formate was prepared from carbon monoxide and methanol in the presence of potassium methoxide as a homogeneous catalyst. Experimental work was carried out in a laboratory-scale semi-batch autoclave to obtain the intrinsic reaction kinetics. The experimental results were described with a plausible reaction mechanism comprising the reaction of potassium methoxide with carbon monoxide, followed by the proton transfer from methanol to the reaction intermediate to restore the catalyst. It was observed that simple first order kinetics fits the experimental data of the catalyst decomposition. A model for the gas–liquid mass transfer, coupled to the synthesis reaction was developed and the reaction of potassium methoxide was assumed to be the rate-determining step. The equilibrium, mass transfer and rate parameters included in the completely new kinetic model were determined with non-linear regression analysis. A comparison of the modelling results with the experimental data illustrated a good agreement between the model and the actual data. The kinetic and mass transfer models can be used for the scale-up of the methyl formate synthesis.

► The kinetics and mechanism of methyl formate synthesis was determined using a laboratory-scale semi-batch reactor. ► Potassium methoxide was used as a catalyst and the catalyst decomposed as the reaction progresses. ► A gas–liquid mass transfer model coupled with synthesis reaction was developed for the system. ► The completely new model was able to describe the experimental results successfully.