Issue 20, 2022

Hydroxylation and dimerization of para-dihydroxylated aromatic compounds mediated by cold atmospheric-pressure plasma in comparison with chemically catalyzed reactions

Abstract

The synthesis of valuable organic compounds is a novel possibility for the application of physical plasma. As model reactants 2,5-dihydroxybenzoic acid derivatives were used and the resulting reactions investigated in detail. The formation of methoxylated and hydroxylated products as well as dimers (biaryls) was mediated by physical plasma in aqueous solution at atmospheric pressure and room temperature. Additionally, nitrated or nitrosated products were assumed. The direct (reactant is part of the liquid which is plasma-treated) and indirect (liquid is treated by plasma and afterwards reactant is added) plasma treatment resulted in a partly different product pattern, but both reaction concepts are suitable for the synthesis of organic compounds. The influence of operating parameters such as duration of plasma treatment, volume of the liquid, or concentration of reactants was varied to study the reaction course in order to increase product yields. Nitrite, nitrate, hydrogen peroxide, a decreased pH-value and an increased temperature was determined for the plasma-treated liquid. Consequently, the reactions with the 2,5-dihydroxybenzoic acid derivatives were pursued in the presence of these compounds at acidic pH-value and 50 °C. As result, nitrite, a low pH-value (pH = 2.2) and an elevated temperature were at least in part responsible for the formation of the products. The advantages of plasma-mediated synthesis are discussed in detail. The environmentally friendly reaction conditions without the need for catalysts or buffer components recommend physical plasma as novel mean in green chemistry.

Graphical abstract: Hydroxylation and dimerization of para-dihydroxylated aromatic compounds mediated by cold atmospheric-pressure plasma in comparison with chemically catalyzed reactions

Supplementary files

Article information

Article type
Paper
Submitted
30 اپریل 2022
Accepted
02 اگست 2022
First published
10 اگست 2022

Green Chem., 2022,24, 7951-7967

Hydroxylation and dimerization of para-dihydroxylated aromatic compounds mediated by cold atmospheric-pressure plasma in comparison with chemically catalyzed reactions

V. Hahn, A. Mikolasch, M. Schmidt, J. E. Neuburger, J. von Langermann, M. Lalk, K. Weltmann, T. von Woedtke and J. Kolb, Green Chem., 2022, 24, 7951 DOI: 10.1039/D2GC01624A

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements