Reaction Mechanisms of Synthesis of 3,4-Epoxybutyric Acid from 3-Hydroxy-{\gamma}-Butyrolactone by Density Functional Theory

TL;DR

This study uses density functional theory to analyze the reaction mechanisms of synthesizing 3,4-epoxybutyric acid from 3-hydroxy-{ extgamma}-butyrolactone with different activating agents, revealing differences in activation energy and potential by-products.

Contribution

It provides a theoretical comparison of reaction pathways and energy barriers for EBA synthesis using methanesulfonyl chloride and acetic acid, explaining experimental yield differences.

Findings

Activation energy with AA is 1.8 times higher than with MC.

Reaction mechanisms are nearly identical for both activating agents.

Higher activation energy with AA leads to more by-products and lower yield.

Abstract

In this paper, carried out were the investigations on the synthetic reaction mechanisms of 3,4-epoxybutyric acid (EBA) from 3-hydroxy-{\gamma}-butyrolactone (HBL) with two different activating agents, methanesulfonyl chloride (MC) or acetic acid (AA), respectively, and on the convertion of EBA to L-carnitine by density functional theory (DFT/B3LYP). The theoretical calculations showed that the two reaction mechanisms of EBA synthesis with MC or AA as an activating agent were nearly the same. If activated HBL is hydrolysed, not only ring cleavage reaction, but also reverse reaction to HBL can take place. In the case of AA as the activating agent, the activation energy ( energy barrier ) for EBA synthesis is 1.8 times larger than that with MC. It means that the synthesis of EBA with AA may make more by-products with less yield of EBA than that with MC, that can be one reason why AA gave the less yield than MC in EBA synthesis, as reported in the previous experimental study.