Dimethyl Sulfoxide (DMSO)

DMSO is the classic polar aprotic solvent. It's used in lots of known reactions. Why should I worry?

DMSO decomposes with heating, and the decomposition products catalyze further decomposition, resulting in a runaway reaction that has caused explosions resulting in injuries and deaths. A wide range of other reagents (oxidizers, reducers, bases, and especially acids) can accelerate the decomposition, or cause the decomposition to occur at much lower temperatures (some as low as 20°C), thus increasing the hazard whenever DMSO is used as a solvent.

In situations where a safer solvent cannot be substituted for DMSO, evaluate the usage conditions within the context of the following papers and review:

https://pubs.acs.org/doi/pdf/10.1021/acs.oprd.0c00113

https://pubs.acs.org/doi/pdf/10.1021/acs.oprd.0c00159

If the reaction conditions have any potential to initiate DMSO decomposition, your lab must develop a written Standard Operating Procedure (SOP) that specifies safeguards, such as limitations on reaction scale and the use of a blast shield, and send the SOP to your lab manager and FSE Safety for review (see the new/changed chemical approval process for details).