(17a) A Mechanistic and Experimental Study of the Diethyl Ether Oxidation

A large number of organic compounds, such as ethers, spontaneously form unstable peroxides through a self-propagating process of autoxidation (peroxidation) based on free radical reactions if stored under poor conditions or for over-long period in contact with air. However, few works are focused on the mechanistic study of their oxidation. This work presents a theoretical study of autoxidation process of diethyl ether (DEE), a chemical largely used as solvent in laboratories and considered to be responsible for various accidents.

Based on Density Functional Theory (DFT) calculations, the aim was to identify all the most probable reaction paths involved in the DEE oxidation process (at ambient temperature and under conditions that reflect normal storage conditions) and to characterize products and potential hazardous intermediates, such as peroxides. Results indicate that industrial hazards could be related to hydroperoxide formation and accumulation during the chain propagation step. A detailed kinetic model of the oxidation process of DEE was then developed from energetic and kinetic parameters collected in this mechanistic study. Outputs of the kinetic model, in terms of evolution of concentrations of products, have been compared with the experimentally measured ones (notably hydroperoxides) issued from tests on DEE oxidation conducted under accelerated conditions with autoclaves.