The phase equilibria of four subsystems related to the gamma-valerolactone (GVL) based biorefinery concept were measured. The liquid liquid equilibrium (LLE) is important in separating GVL from aqueous solution with the aid of carbon dioxide. LLE of dense carbon dioxide, GVL, and water at 7.5 MPa was measured in a high pressure equilibrium cell equipped with a pneumatic capillary sampler. The solubility of GLV was from 2 to 10 times higher in the dense CO2 phase than in the aqueous phase indicating CO2 is a good solvent for this separation. The vapor liquid equilibrium of furfural and GVL is important in the separation of traces of furfural from GVL in solvent recycling. It was found that furfural and GVL is a very ideal binary system at subatmospheric pressure. The predictive SRK (PSRK) equation of state and UNIQUAC activity coefficient model were used to model the binary and ternary systems measured in this work.