High-Pressure Densities and Derived Thermodynamic Properties of Imidazolium-Based Ionic Liquids Gardas, R.L.; Freire, M.G.; Carvalho, P.J.; Marrucho, I.M.; Fonseca, I.M.A.; Ferreira, A.G.M.; Coutinho, J.A.P.; Journal of Chemical & Engineering Data 2007, 52, 80-88