Carbon dioxide solubility in ionic liquids: [Guad-(6,6),(1,1),(1,1)][DCA] and [Guad-(6,6),(1,1),(1,1)][TCM] at high pressure

•Solubility of Carbon Dioxide in guanidinium-based ionic liquids was measured for the first time.•Experiments were conducted on temperatures (298.15, 313.15 and 323.15) K and pressures ranged from 0.1 MPa to 2 MPa.•The experimental data were modelled using the Peng-Robinson EoS and extended Van der Waals mixing rule.•The glass transition temperature, heat capacity change at glass transition, density and viscosity of new ILs were measured.