Decomposition of Pyruvic Acid on the Ground-State Potential Energy Surface

Abstract

A potential energy surface is reported for isomerization and decomposition of gas-phase pyruvic acid (CH3C(O)C(O)OH) in its ground electronic state. Consistent with previous works, the lowest energy pathway for pyruvic acid decomposition is identified as decarboxylation to produce hydroxymethylcarbene (CH3COH), with overall barrier of 43 kcal mol-1. This study discovers that pyruvic acid can also isomerize to the α-lactone form with a barrier of only 36 kcal mol-1, from which CO elimination can occur at 49 kcal mol-1 above pyruvic acid. An additional novel channel is identified for the tautomerisation of pyruvic acid to the enol form, via a double H-shift mechanism. The barrier for this proc..