A reaction density functional theory study of solvent effects on keto-enol tautomerism and isomerization in pyruvic acid

It is important to study the solvent effect on keto-enol tautomerism that has applications in many areas of chemical engineering. In this work, we use a multiscale reaction density functional theory (RxDFT) to study the keto-enol tautomerism and isomerization of pyruvic acid. The results show that both effects of solvation and water assistance could reduce the reaction barriers. The water molecule participates the reaction as a catalyst to accept/give the protons with forming a hexagonal ring in the transition state. As a result of this temporary and intermediate hexagonal ring, the solute configuration undergoes a small variation during the reaction, giving a diminished contribution to the intrinsic reaction free energy. The solvent distribution shows a local ordering behavior near the solute that also reduces the contribution of solvation effect to the reaction barrier. Water assistance plays a major role in both pre-reaction and post-reaction process. In terms of the driving force for the reaction, the effects of both solvation and water assistance are important. (C) 2020 The Chemical Industry and Engineering Society of China, and Chemical Industry Press Co., Ltd. All rights reserved.

Automated summary

This study investigated the mechanism of keto-enol tautomerism and isomerization using multiscale reaction density functional theory. The results showed that solvent and water assistance effects reduce the reaction barriers, with water molecule acting as a catalyst by forming a hexagonal ring in the transition state.