Abstract:
Aromatic compounds, distinguished by their unique physicochemical properties, play crucial roles in the chemical, pharmaceutical, and material industries. However, traditional synthetic methods are associated with high costs and complex procedures. New possibilities for the preparation of aromatic compounds are offered by China’s abundant coal resources. Costs are effectively reduced and synthesis processes are simplified by extracting aromatic compounds from coal. Although the coal structure is complex, with diverse covalent bonds and great dissociation difficulty, a solution is provided by radicals, which weaken chemical bonds and promote the cleavage of chemical bonds in coal, thereby facilitating the extraction of aromatic compounds Utilizing demineralized Linfen fat coal as the raw material, extraction techniques combined with pyridine solvent and initiators that lower bond energies effectively depolymerized coal structures, significantly improving extraction efficiency and aromatic compound yield. A full comparison of the composition of detectable components in the extraction products with and without initiators, the distribution of fractions and the differences in the structure of extracted coal showed that the extraction rate of Linfen coal increased after the addition of different initiators, and the highest extraction rate reached 35%; The detectable fraction of the extraction product contains a high number of large aromatic compounds, higher heavy fraction content, and alterations in residual coal properties, including longer methylene chains, increased branches on aromatic clusters, reduced graphitization, elevated surface oxygen functional groups, and enhanced weight loss rates around 460 ℃. It is thus verified that under mild conditions, certain oxidative and depolymerization effects on the coal structure are exerted by the initiators, depolymerized coal structures are produced, and the extraction yield is raised. A theoretical basis is expected to be provided for the directional depolymerization of coal to produce high-value aromatic compounds.