Dimethyl sulfoxide (DMSO) is widely used due to its excellent solvent properties; however, several serious incidents have been reported related to the use of DMSO. DMSO can decompose autocatalytically, but we have no consensus with respect to the chemical structure and function of the autocatalyst. Thermal decomposition of DMSO was carried out in an inert atmosphere, and analysis of the nonvolatile fraction indicated the presence of several organic and inorganic acids. DMSO was believed to act as an oxidizer as well as a reactant in the formation of these acids. The same acids were found in an isothermal heating test, and their concentrations increased over heating time. Addition of acids to DMSO before starting isothermal heating significantly shortened the induction period indicating that the acids generated in situ served as autocatalysts for the thermal decomposition of DMSO.

Self-assembling phenylalanine-based peptides have garnered interest owing to their potential for creating new functional materials. l-Phe-l-Phe-d-Phe tripeptide forms a γ-turn structure in the nanostructure.

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A simple model based on a quantum chemical approach with polarizable continuum models (PCMs) to provide reasonable translational and rotational entropies for liquid phase molecules was developed.

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Ammonium dinitramide (ADN; [NH4]+[N(NO2)2]-) is the most promising oxidizer for use with future green solid and liquid propellants for spacecraft applications. To allow the effective development and use of ADN-based propellants, it is important to understand ADN reaction mechanisms. This work presents a detailed chemical kinetics model for the liquid phase reactions of ADN based on quantum chemical calculations. The thermal corrections, entropies, and heat capacities of chemical species were calculated from the partition function using statistical machinery based on the G4 level of theory. Rate coefficients were also determined to allow the application of transition state theory and variational transition state theory to reactions identified in our previous study. The new model employed herein simulates the thermal decomposition of ADN under specific heating conditions and successfully predicts heats of reaction and the gases that result from decomposition under those conditions. The thermal behaviour predicted from the new model was an excellent match with the experimental behaviour observed from thermal analysis using differential scanning calorimetry and Raman spectroscopy. The new kinetic model reveals the mechanism for the decomposition of ADN.

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