In Situ FTIR Spectroscopy as a Kinetic Study Tool for Potassium Butyl Xanthate Industrial Production

Abstract In situ FTIR spectroscopy was used for the first time to study the kinetics of the potassium butyl xanthate synthesis from butanol, carbon disulfide, and potassium hydroxide under conditions as close as possible to the industrial method. This method allowed us to obtain kinetic curves for the first time at high conversions of the starting reagents, determine the boundaries of the process kinetic region, and develop a kinetic model that takes into account not only the main reaction but also the side processes. The main reaction kinetic equation confirms the two-stage mechanism of the xanthation reaction as proposed in the literature. In the first stage, the alcoholate anion forms rapidly in equilibrium, and it adds to carbon disulfide in the second rate-limiting stage. Due to the specific mechanism of the studied process, the main reaction kinetic equation includes the concentration ratio of BuOH and H2O. The rate of potassium butyl xanthate formation directly depends on the concentrations of BuOH, CS2, and KOH and inversely depends on the concentration of H2O since the concentration of H2O reduces the butylate anion concentration. The key parameters influencing process selectivity (temperature and the BuOH:H2O molar ratio) were determined. The kinetic model demonstrates good agreement with the experimental data. The obtained results can be used to optimize the potassium butyl xanthate industrial production conditions.