In this work, two Turkish coals were extracted with N-methyl-2-pyrrolidone (NMP) and NMP containing a small
amount of ionic liquids (ILs) under reflux conditions at atmospheric pressure. The effects of coal type, ionic
liquid type, ionic liquid-to-coal ratio, and ultrasonic interactions on extraction yield were investigated. The ILs
used were: 1-butyl-3-methylimidazolium chloride ([Bmim]Cl), 1-buty-4- methylpyridinium chloride ([Bmp]Cl),
1-ethyl-3-methylimidazolium chloride ([Emim]Cl), and 1-butyl-2,3-dimethylimidazolium chloride ([Bdmim]Cl).
It was found that the extraction yield of coals using NMP/ILs varied with coal type, IL type and amount of IL. ILs
were effective on the extraction of Afsin-Elbistan (AE) lignite, but not on the extraction of Üzülmez (UZ) coal. A
significant increase in extraction yield for AE lignite was observed when a small amount of IL was added into
NMP. It was determined that [Bmim]Cl was the most efficient IL used for the extraction of lignite compared to
the others ILs used, and the extraction efficiency was found to increase by increasing the amount of ionic liquid
added into NMP.