Oxidation of propylene with oxygen, air in a barrier discharge plasma is investigated. The selectivity towards formation of propylene oxide in pure oxygen is shown to be as high as 45 wt. % and the propylene conversion ratio is found to be 12.9 wt. %. In the oxidation with air, the propylene oxide selectivity is 23 wt. %, while the conversion is 7.5 wt. %. The values of propylene conversion and selectivity towards formation of propylene oxide in a barrier discharge are consistent with those obtained by the thermocatalytic methods for production of propylene oxide.
The oxidation of cumene with oxygen in a barrier discharge under conditions of effective removal of reaction products from the reactor has been studied. The experiments were carried out on a setup with an electrochemical reactor with a barrier discharge in a flow mode. The results are presented in comparison with the previously studied oxidation of benzene and toluene. The main products of cumene oxidation are acetophenone and dimethylphenylcarbinol, the total selectivity of which reaches 78%wt. Phenol and other compounds with a hydroxyl group in the aromatic ring were not found in significant amounts. Cumene conversion in the studied temperature range varies from 1.0%wt to 1.2%wt. In the case of toluene, the main products are cresols, benzaldehyde and benzyl alcohol (in total 77%wt). The main product of the oxidation of benzene is phenol (up to 74% by weight), diatomic phenols, mainly hydroquinone, also are found. Based on the research results, a probable mechanism of oxidation of aromatic hydrocarbons by oxygen in a barrier discharge is proposed. It is shown that the general direction of oxidation of aromatic hydrocarbons is determined by the contribution of two processes of its oxidation – with the participation of atomic oxygen and along the route of autooxidation. The data obtained make it possible to reasonably predict the composition of oxygen oxidation products of various aromatic hydrocarbons under barrier discharge conditions. The revealed regularities make it possible to evolve methods for controlling the oxidation of aromatic hydrocarbons in a low-temperature plasma of a barrier discharge based on temperature control of the process. The results obtained will become the basis for the development of new environmentally friendly methods of organic synthesis involving aromatic compounds using low-temperature nonequilibrium plasma of various discharges, including barrier, in accordance with the principles of "green chemistry". For citation: Leshchik A.V., Ochered'ko A.N., Ryabov A.Yu., Kudryashov S.V. Oxidation of alkylaromatics by oxygen in the dielectric barrier discharge. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2024. V. 67. N 8. P. 15-21. DOI: 10.6060/ivkkt.20246708.16t.
