Chain reaction mechanism study of active groups in coal

This study investigates the chain reaction mechanisms of active groups during low-temperature coal oxidation using FTIR spectroscopy and Materials Studio simulations. Hydroxyl, methyl , carbonyl, and carboxyl groups were identified as key reactive species. FTIR analysis revealed that -OH oxidizes to form H 2 O between 30-90°C, while oxygen-containing groups remained stable initially and increased significantly in later stages. Aliphatic hydrocarbon side chains were oxidized to generate -CH 3 /-CH 2 , which were further consumed to produce hydrocarbon gases. Aromatic hydrocarbons showed minimal reactivity at low temperatures. Reactivity analysis demonstrated distinct trends: individual groups followed -CHO> -COOH> -CH 3 , whereas within the coal molecular structure, the order shifted to -COOH > -CH3 > -CHO. Simulations of oxidation pathways identified the key intermediates and energy barriers for CO/CO 2 formation. Results indicated that functional group reactivity depends on nucleophilic reaction sites rather than energy gap values, with temperature predominantly enhancing product formation over transition state activation.The chain reaction of reactive groups in coal provides theoretical support for understanding the coal-oxygen interaction mechanism and guides efforts to curb spontaneous coal combustion.