Method for separation of phenols and bases from coal tar oils by extraction

摘要

Coal tar oil is separated quantitatively into neutral oil, phenols and bases by a two stage extraction with overcritical gases. Carbon dioxide is employed as an overcritical extraction agent, and propane or butane are preferably added as entrainers. The neutral oil is obtained in the first stage. Tar bases can be employed as an additional entrainer for improving the selectivity. The bases are extracted in the second stage. The method is associated with the advantage that it saves energy and that no byproducts are generated.