The gas-liquid phase equilibrium experimental system based on the isochoric saturation method in the laboratory was improved. The visual equilibrium cell

thermostatic system and magnetic stirring system were modified. In order to check the reliability and accuracy of the new system

the phase equilibrium of carbon dioxide and pentaerythritol tetrahexanoate was measured at 303.15 K

the absolute average deviation was 0.95% and the maximum deviation was 2.01% compared with the reference data. The expanded uncertainties of temperature

pressure and mole fraction are 0.03 K

2.0 kPa

and 3.0%

respectively. Phase equilibria behavior of trans-1

3

3

3-tetrafluoropropene and squalane was determined at temperature range from 283.15 K to 348.15 K. The experimental data were correlated with Peng-Robinson equation of state and van der Waals mixing rule using two interaction parameters. The absolute average deviation between experimental data and calculated values for pressure was 0.88%

and the maximum deviation was 3.80%. In addition

the immiscibility phenomenon for trans-1

3

3

3-tetrafluoropropene and squalane mixtures was found in the temperature range from 283.15 K to 333.15 K.