Calorimetric Study of the Exothermic Decomposition of Dimethyl Sulfoxide

Dimethyl sulfoxide (DMSO) is a widely-used solvent often employed for a variety of organic syntheses. It is stable at room temperature, can dissolve many types of organic materials, and is miscible in water.  However, upon heating in a closed system under conditions typically achievable in a commercial chemical plant, DMSO undergoes significantly exothermic and hazardous decomposition which could realistically lead to a pressure vessel explosion unless an adequate pressure relief system were installed. This study provides calorimetry data from several apparatus and methods to characterize the decomposition. The results are described, and a simplified kinetic model is presented to correlate the data, useful for relief system design.