Phase Diagram,Non-ideal Mixing Properties And Thermodynamic Analysis Of The Association System Of Acetic Acid-cyclohexane

Cyclohexane oxidation of cyclohexanol and cyclohexanone is the key to the production of nylon in the industry.It has been found that the conversion of cyclohexane can be greatly improved by the use of acetic acid as the solvent in the oxidation of cyclohexane.Therefore,the non-ideal mixing properties and phase equilibrium data of acetic acid-cyclohexane are critical to the design and operation of this process.1 Measured at atmospheric pressure acetic acid-cyclohexane Binary of pure components and mixture density in the whole concentration range 293.15-313.15 K temperature,calculating the volume of the mixing system Vm^E molar excess to give acetic acid-cyclohexane.The system V_m^E is positive.The relationship between V_m^E and the mole fractions of the study system at different temperatures was correlated with the Redlich-Kister equation.The interaction between polar organic solvents and other organic compounds was discussed.2The partially miscible phenomenon of acetic acid-cyclohexane was observed for the first time and the LLE data were systemically measured by the static equilibrium method.It was found liquid-liquid equilibrium of the system was present in the temperature range 280 to 300 K and at the acetic acid mole fraction from 0.275 to 0.875.The two-phase region gradually diminished with an increase of temperature and when it was above 300 K,only one single liquid phase was observed.3 The solid-liquid equilibrium data of the pure component of acetic acid-cyclohexane binary mixture system and the whole concentration range of the mixed solution at 270.15-290.15 K were measured by using the new online real-time measuring homemade equipment.When the molar fraction of acetic acid is less than 0.1151,the mixed solution and cyclohexane solid are obtained.When the mole fraction of acetic acid is more than 0.1151,the mixed solution and acetic acid solid are obtained.When the temperature is below 272.45 K,only the solid is obtained.4The liquid-liquid,solid-liquid equilibrium data and the vpour-liquid equilibrium data in the previous literature was used.The thermodynamic model was correlated by NRTL and UNIQUAC equations.By fitting the NRTL equation and the UNIQUAC equation.The binary-interaction parameters of NRTL and UNIQUAC model were obtained for the measured vpour-liquid,liquid-liquid and solid-liquid equilibrium data.The results show that the NRTL and UNIQUAC models can be used for the vpour-liquid,liquid-liquid and solid-liquid equilibrium data of acetic acid-cyclohexane.The binary interaction parameters of NRTL and UNIQUAC models can also be used to simulate and calculate the vpour-liquid,liquid-liquid and solid-liquid equilibrium processes of acetic acid-cyclohexane system.The vapor-liquid,liquid-liquid and solid-liquid equilibrium phase diagrams of the acetic acid-cyclohexane binary system under atmospheric pressure were established for the first time through the construction of the model.