Measurement of relative static permittivity and solvatochromic parameters of binary and ternary CO2-expanded green solvents

•Experimental data for relative static permittivity and solvatochromic parameters.•Large range of dielectric properties obtained for one-phase CO2-expanded liquids.•Ternary green solvent mixtures with CO2 + ethanol/ethyl lactate+ glycerol/water.•Novel data for relative static permittivity of CXLs using an in-line microchip.•Relative static permittivity of up to 75 with CO2 +ethyl lactate + water.