Can Solvent Choices Enhance Both Process Safety and Efficiency?

Recent work has demonstrated that the decomposition characteristics of individual chemicals are often substantially different from those of the same chemical when combined with a solvent. Further, different solvents alter the decomposition in significantly different ways, shifting the observed Differential Scanning Calorimeter (DSC) onset and peak temperatures and maximum rates to lower as well as higher values. Often the magnitude of these effects cannot be explained as the result of simple dilution. This prior work with energetic materials in solvents emphasizes the importance to process safety of systematically testing reaction mixtures, in addition to testing individual chemicals. The primary focus of such testing is to ensure the hazards of the process are well understood so that the process can be modified, or additional necessary preventative and protective systems can be implemented to minimize process upsets. However, it is demonstrated here that this knowledge can also be leveraged to modify processes to substantially increase process efficiency while maintaining or enhancing safety. For example, the batch size of an existing process had been very restricted because of the potential severity of a thermal runaway. Research on chemistry/solvent-specific decomposition data was utilized to select candidate replacement solvents for process optimization. A cooperative effort by safety engineers and development chemists ensued, resulting in a final process that entirely eliminated the batch size restrictions while simultaneously reducing reaction time and improving product quality.