(67b) Case Study - Characterizing and Averting Risk of Catastrophic Vessel Failure for a Reaction in Dimethyl Sulfoxide (DMSO)

Case Study - Characterizing and averting risk of catastrophic vessel failure for a reaction in dimethyl sulfoxide (DMSO)

Author: Megan Roth, Merck & Co., Inc., Kenilworth, NJ, USA

The Environmental & Process Safety Engineering (EPSE) group at Merck & Co., Inc., Kenilworth, NJ, USA has the responsibility to characterize the desired and undesired process chemistry for synthesis of pharmaceutical candidates in order to mitigate low/moderate risks and avoid high risk processes.

Process safety testing performed on a batch process for making a pharmaceutical intermediate revealed that one process stream, a reaction in dimethyl sulfoxide (DMSO), had a significant undesired reaction that could lead to catastrophic vessel failure as a result of a single process deviation. Comprehensive testing identified the worst-case process stream with the lowest exotherm initiation temperature (EIT) and most severe pressure consequences, for which corrective actions must be taken. With this information in hand, hazard assessments were performed to support processing; to determine the appropriate safeguards needed to mitigate the consequences and reduce the likelihood of reaching this activity to an acceptable level.

This case highlights stream composition impact on the initiation and extent of exotherms, autocatalytic decomposition, the benefit of a solvent barrier to dissipate an exotherm, and the consequences of using a reactive solvent.