Influence of organic acid on the thermal behavior of dimethyl sulfoxide

Abstract

Dimethyl sulfoxide (DMSO) has been extensively used as a solvent because of its high-performance characteristics. However, there have been accidents when DMSO has been used in some chemical processes (Lam et al. in J Therm Anal Calorim 85:25-30, 2006; http:// riscad.db.aist.go.jp/PHP_EN/index.php). Although the decomposition mechanism of DMSO under acidic conditions is known (Santosusso et al. in Tetrahedron Lett 48:4255-4258, 1974), the number of studies about thermal behavior of DMSO under acidic condition is not large. The purpose of this investigation is to understand the decomposition thermal behavior of DMSO under acidic conditions. Thermal analysis using an accelerating rate calorimeter (ARC) was carried out with acids chosen for their acid dissociation degree constant (pKa), which is a typical parameter of acid strength. ARC data show that the self-heat rate increased and the exothermic onset temperature decreased with decreasing pKa. Additionally, the exothermic onset temperature and pKa had good linear correlation. To verify the initial exothermic reaction, differential scanning calorimetry (DSC) analysis was carried out. DSC results showed that the exothermic onset temperature was due to decomposition of DMSO. The activation energy of the decomposition reaction was calculated from the ARC results (self-heat rate). Our data indicate that the activation energy of the decomposition reaction decreased with decreasing pKa. Therefore, thermal hazards of DMSO increase with the decrease in pKa, with good linear correlation.

Rh‐Catalyzed Hydrogenation of CO2 to Formic Acid in DMSO‐based Reaction Media: Solved and Unsolved Challenges for Process Development

“…The decomposition of DMSO has been topic of previous investigations and several pathways lead to the observed decomposition products . While highly pure DMSO can be heated to its boiling point of 189 °C with only minor decomposition, small impurities can lead to an increased decomposition . In the present case, the acidic conditions strongly facilitate the decomposition of DMSO (Scheme ).…”

Potential Explosion Hazards Associated with the Autocatalytic Thermal Decomposition of Dimethyl Sulfoxide and Its Mixtures

“…The respective total energy releases (> −739 J/g and > −792 J/g) were also larger than their reported value for pure DMSO (−668 J/g) (Table ). Babasaki et al reported DSC and ARC evaluations of the thermal stability of DMSO in the presence of organic acids such as phenol, acetic acid, benzoic acid, and 2,2,5-trimethyl-1,3-dioxane-4,6-dione (methyl Meldrum’s acid) . In all cases, the presence of acid reduced the onset temperature of DMSO decomposition and increased the total energy release (Table ).…”

“…Babasaki et al reported DSC and ARC evaluations of the thermal stability of DMSO in the presence of organic acids such as phenol, acetic acid, benzoic acid, and 2,2,5-trimethyl-1,3-dioxane-4,6-dione (methyl Meldrum's acid). 32 In all cases, the presence of acid reduced the onset temperature of DMSO decomposition and increased the total energy release (Table 3). DSC evaluation of a mixture containing 11.3% aqueous hydrochloric acid (HCl, 37 wt %) and 88.7% DMSO performed in our laboratory revealed two exothermic events.…”

Thermal and kinetic analyses on Michael addition reaction of acrylic acid

“…Generally, the thermal kinetic parameters (e.g., activation energy and reaction order) can be obtained from thermal analysis, which is conducted under non-isothermal conditions [19] or adiabatic conditions [20]. However, the thermal behavior of MAR is thought to be too slow and mild to detect.…”