Ultrasonic-Assisted Technique as a Novel Method for Removal of Naphthenic Acid from Model Oil Using Piperidinium-Based Ionic Liquids.

In this study, piperidinium-based ionic liquids (IL) containing trifluoromethanesulfonate, phenolate, and dicyanamide anions were synthesized. Using the ILs, extraction of naphthenic acid from highly acidic oil with a total acid number (TAN) of 1.44 was studied.