Oxidation mechanism of diethyl ether: a complex process for a simple molecule

Abstract

A large number of organic compounds, such as ethers, spontaneously form unstable peroxides through a self-propagating process of autoxidation (peroxidation). Although the hazards of organic peroxides are well known, the oxidation mechanisms of peroxidizable compounds like ethers reported in the literature are vague and often based on old experiments, carried out in very different conditions (e.g. atmospheric, combustion). With the aim to (partially) fill the lack of information, in this paper we present an extensive Density Functional Theory (DFT) study of autoxidation reaction of diethyl ether (DEE), a chemical that is largely used as solvent in laboratories, and which is considered to be responsible for various accidents. The aim of the work is to investigate the most probable reaction paths involved in the autoxidation process and to identify all potential hazardous intermediates, such as peroxides. Beyond the determination of a complex oxidation mechanism for such a simple molecule, our results suggest that the two main reaction channels open in solution are the direct decomposition (β-scission) of DEE radical issued of the initiation step and the isomerization of the peroxy radical formed upon oxygen attack (DEEOO˙). A simple kinetic evaluation of these two competing reaction channels hints that radical isomerization may play an unexpectedly important role in the global DEE oxidation process. Finally industrial hazards could be related to the hydroperoxide formation and accumulation during the chain propagation step. The resulting information may contribute to the understanding of the accidental risks associated with the use of diethyl ether.

Theoretical and Experimental Study of the Reaction between Ammonium Nitrate and Sodium Salts

“…20,[27][28] In particular, a complete Density Functional Theory (DFT) study performed on pure AN, pure SDIC and on the system of AN-SDIC identified all the structures of the intermediates and products involved in the decomposition reactions and clarified the incompatibility between these substances. It evidenced the catalytic role of water in promoting the decomposition of AN when in contact with SDIC through a significant decrease of the activation energy of the rate-determining step of the reaction mechanism.…”

Comment on “Crystallographic Snapshot of an Arrested Intermediate in the Biomimetic Activation of CO2”

“…Additionally, adventitious oxygen in diethyl ether could have initiated the formation of peroxides whose decomposition pathway includes acetic acid or one of its esters. [8] Under the reported preparative conditions, these species could certainly be hydrolyzed and deprotonated to form acetate. In all of these scenarios, a small amount of the acetate salt could be present in the bulk powder and crystallize out from the ether solution.…”

Experimental and Numerical Investigation of Ethanol/Diethyl Ether Mixtures in a CI Engine

“…The rate constants for the scission of CO bonds in ethanol and its radicals were adopted from the theoretical calculations of Al Rashidi et al [41]. Finally, reactions between ethyl peroxy radicals and DEE were added, as these were cited as important in the DEE low temperature oxidation chemistry study by Di Tommaso et al [42]. All simulations were performed with commercial software using the constant volume homogenous batch reactor model [43].…”