A Review on the Extraction of Phenols from Coal Tar: Composition Distribution and Analysis, Methods and Mechanism, Process and Industrialization Prospect

Coal tar is a valuable chemical raw material derived from coal coking/pyrolysis. It is rich in important chemicals and intermediates that cannot be produced by the petrochemical industry and plays a crucial role in the world's chemical supply. Coal tar is rich in phenols, which are crucial chemical raw materials for synthetic fibers, engineering plastics, pesticides, medicine, preservatives, plasticizers, spices, and dye intermediates. In this paper, based on the basic properties of coal tar and the distribution of phenols, the research progress on the composition, structure, and extraction technology of phenols in coal tar was analyzed, and the mechanisms of existing coal tar extraction technologies (acid–base extraction, solvent dissolution, complexation extraction, adsorption separation, liquid–liquid extraction, etc.) were discussed. The advantages and disadvantages of relevant technologies and their practical applications are also compared to analogies. Based on the summary and research experience of our research team, the development of new technologies for extracting phenols from coal tar is under investigation.