Effect of preoxidation treatment with H2O2 on ruthenium ion-catalyzed oxidation of Yima long flame coal

• Published in: Fuel (Guildford) 2022-06, Vol.318, p.123526, Article 123526
• Main Authors: Lv, Jing-Hui, Wang, Ya, Zhang, Yang-Yang, Wei, Xian-Yong, Zhang, Yu-Long, Ma, Ming-Jie, Zong, Zhi-Min, Bai, Hong-Cun
• Format: Article
• Language: English
• Subjects: Acids; Benzenecarboxylic acids; Bonding; Carbon; Carbon dioxide; Carbon dioxide emissions; Carboxylic acids; Coal; Decomposition reactions; Hydrogen peroxide; Intermediates; Macromolecules; Organic matter; Oxidation; Peroxidation; Peroxidation with H2O2; Radicals; Ruthenium; Ruthenium-ion-catalyzed oxidation; Yield increase
• ISSN: 0016-2361; 1873-7153
• DOI: 10.1016/j.fuel.2022.123526

[Display omitted] •PO increases the yields of BCAs, ADAs, and AAs sharply.•PO is more effective to afford BCAs with more carboxylic groups.•PO provides more active sites to significantly raise the yield of AAs and ADAs.•PO promotes the formation of –COOH from other oxygen-containing groups or bonds.•The formation of –COOH is the critical to increase the yield of oxidation products. Environmental concerns have led researches to investigate carbon neutral and sustainable strategies to satisfy well-being of present and future generations, in which coal oxidation becomes a promising approach to achieve this goal. In this study, Yima long flame coal (YLFC) was subjected to ruthenium-ion-catalyzed oxidation (RICO) after peroxidation with H2O2 (PO). The results indicate that the organic matter in YLFC is mainly oxidized into benzenecarboxylic acids, accounting for 70.36% of all the oxidation products, and the yields of the valuable resulting carboxylic acids are significantly elevated by PO from 12.99 wt% to 35.06 wt%, leading to a higher utilization of carbon and lower CO2 emission. Moreover, PO can enhance remarkably the reactivity of the macromolecular precursors of coals, especially highly condensed aromatic species to produce benzenepentacarboxylic acid and mellitic acid more efficiently with a 20-fold increase and 200-fold increase, which is ascribed to the formation of carboxyl groups from other oxygen-containing groups or bonds in coals via PO. The reactive intermediates OH and OOH generated from H2O2 decomposition can attack the carbon atom of alkyl side chains, ether bonds, C=O bonds, and the bridged linkages to undergo a preliminary degradation of macromolecular networks in coals and produce more active sites for the subsequent RICO, leading to the yield and species number increase of carboxylic acids via PO.