... PF 6 , or [buPy]BF 4 which provides a simple and efficient method for the synthesis of the ... The ionic liquids [bmim][BF 4 ], [bmim]PF 6 and [buPy]BF 4 were synthesized according to reported ... KOH (0.336 g, 6 mmol) and heterocycle (3 mmol) were added to ionic liquid (2 mL), and ...