Synthesis and properties of a novel room-temperature ionic liquid hexaalkylguanidium salts

The synthesis and properties of a novel room-temperature ionic liquid hexaalkylguanidium salts 4 and 5 were reported. The reaction of 1, 3-dimethyl-2-imidazolidinon with POCl3 and n-BuNH2 afforded to pentaalkyl-guanidine(2), which reacted with CH3I generated hexaalkylguanidium(3). The hexaalkylguanidium salts 4 and 5 were synthesized by the reaction of hexaalkylguanidium(3) with KPF6, AgBF4 respectively. The results showed that both compounds 4 and 5 were room-temperature ionic liquids. The structures of these compounds were determined by H-1 NMR, C-13 NMR, IR and MS spectra data. Compounds 4 and 5 were found to have better solublities in organic solvents and better thermal stabilities.