The Thermal Runaway of a Hydrogen-Transfer Reaction

Abstract

A thermal runaway is reported which occurred during the conversion of an unsaturated alcohol to the saturated ketone via internal hydrogen transfer. An unexpected and extremely rapid rise in temperature and pressure was observed when the reaction was run at production scale. The vessel was able to withstand the pressure generated, and no injury or damage resulted. The possible causes of this incident are considered here. It should be noted that whilst the rate of a hydrogenation reaction can generally be controlled by the rate of addition of hydrogen, this may not be the case where the possibility of internal hydrogen transfer exists, whether by design or unintentionally. Unsaturated alcohols are perhaps less obvious, although they are very good examples of molecules where such a possibility exists. Our pre-scale-up reaction hazard assessment protocol now considers this point specifically.