Free radical in coal is one of the primary factors to induce coal spontaneous combustion of, and the essence of effectively preventing spontaneous combustion of coal is to inhibit the promotion of oxidation reactions by reactive free radicals in coal. The reactions of reactive radicals in coal(oxygen-containing radicals and aliphatic hydrocarbon radicals) in the process of coal spontaneous combustion were systematically summarized, and the inadequacies of the current research on coal spontaneous combustion mechanism were pointed out, such as the single type of coal molecular models which only considered the reaction process of oxygen-containing radicals in coal, but not consider the reactions in the presence of oxygen-containing radicals, defects and heteroatoms in coal at the same time. The research mostly focused on the pathways of CO₂, H₂O and CO generation, without a proper explanation of the toxic gases such as SO₂ and H₂S produced by coal spontaneous combustion.Secondly, from the perspective of reactive free radicals in coal, the application research of prepared antioxidants was analyzed in a targeted manner, which will be an effective path to prepare green and efficient flame retardants in the future. It was proposed that the molecular structure of the maceral of coal can be studied in terms of their different physicochemical properties, so it was crucial to identify the maceral in different coals, especially the types of their internal reactive radicals.

coal spontaneous combustion  /  aliphatic side chains  /  oxygen-containing functional groups  /  quantum chemistry  /  flame retardants