(60bq) Explosion Hazards of Sodium Hydride with Polar Aprotic Solvents

The explosion hazards associated with the thermal decompositon of chemically incompatibility between sodium hydride (NaH) and polar aprotic solvents are known, with reports from the 1960’s detailing the inherent instability of NaH/N,N-dimethylformamide (DMF), NaH/N,N-dimethylacetamide (DMAc), and NaH/dimethyl sulfoxide (DMSO) mixtures. These hazards, however, remain underappreciated and under-communicated, likely as a consequence of their widespread use in synthetic chemistry. Four major organic chemistry titles publish over 120 papers a year with these reagent combinations in the experimental sections and severe explosions have been reported for over fifty years. This study report detailed investigations into the thermal stability of these mixtures with DSC and ARC. A loading of 4.5 grams of a mixture of 84% DMSO and 9.7% NaH made a detonation around 90C during the ARC test. The formation of gaseous products from thermal decompositions was also studied with EGA Micro-GC analysis and Headspace GC/MS. The authors expect this study to promote awareness of these hazards within the wider scientific community, encourage scientists to identify and pursue safer alternatives, and most importantly, help to prevent incidents associated with these reactive mixtures.