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The experimental data of vapor–liquid equilibrium for the binary systems methyl acetate + 1–propanol, methyl acetate + 1–butanol and ethyl acetate + 1–propanol at 1.5 MPa has been obtained, using an ebulliometer made of stainless steel. This equipment works through the Cottrell pump effect, so that the liquid and vapor phases are recirculated. The isobaric data T–x–y are informed and analyzed with respect to the literature data. The evolution of the azeotropic point with the pressure in the binary system of ethyl acetate + 1–propanol is included. The thermodynamic consistency of the systems was verified by employing the Peng–Robinson equation of state in different forms and using the φ–φ approach.

Highlights • Carbon dioxide + propane mixtures are studied through accurate measurements of speeds of sound and phase equilibria. • Heat capacities and virial coefficients are obtained from speeds of sound. • Retrograde condensation zone is found for the (0.60 CO2 + 0.40 C3H8) mixture. • Results are compared with reference equations of state such as GERG-2008 and AGA8-DC92. This work presents phase envelope and speed of sound data for the (0.60 CO2 + 0.40 C3H8) and (0.80 CO2 + 0.20 C3H8) binary mixtures. Phase equilibria was measured using a cylindrical resonator working in the microwave band whereas an acoustic resonator was used for speed of sound measurements. The experimental results were compared with GERG-2008 equation of state, obtaining average absolute deviations by 0.24% in pressure for phase equilibria data and 0.025% for speed of sound data. Speed of sound values were used to derive perfect-gas heat capacities, acoustic virial coefficients, and second density virial coefficients. In addition, AGA8-DC92 equation of state performance was checked for the results derived from speeds of sound.

The vapor–liquid equilibrium of binary mixtures of propyl acetate, butyl acetate and isobutyl acetate with methanol has been determined at a constant pressure of 0.6 MPa. Results have been modeled with the Peng–Robinson equation, a traditional cubic equation of state widely employed in chemical industries, as well as with the perturbed-chain statistical associating fluid PC-SAFT theory of Gross–Sadowski. By correlation of the binary interaction parameters of these equations, the measured vapor–liquid equilibrium data can be accurately predicted. Thus, this work shows that these models are able to represent the experimental data for systems with associating compounds via hydrogen bonding.

We report viscosities of liquid hexadecane measured at temperatures between 323 K and 673 K and at pressures up to 4.0 MPa. This study significantly extends the temperature range over which viscosity data for hexadecane are available. The experiments were carried out using a dual-capillary viscometer that measures the ratio of the viscosity at the temperature in question to that at a reference temperature, 298.15 K in this work, at which the viscosity is well known. Absolute viscosities were then obtained with an estimated expanded relative uncertainty of about 3% at 95% confidence. An empirical function was developed to correlate the viscosity ratio with the density ratio and this fitted the experimental data within about 1%. The results were found to agree well with the existing literature data.

Producción Científica, The development of a novel technique based on a cylindrical microwave resonator for high pressure phase equilibrium determination is described. Electric permittivity or dielectric constant is a physical property that depends on temperature and pressure ε(p,T). Based on this property, a measuring technique consisting of a cylindrical resonant cavity that works in the microwave spectrum has been developed. Equilibrium data of fluid mixtures are measured at high pressure using a synthetic method, where phase transition is determined under isothermal conditions due to the change of the dielectric constant. This technique may be a more accurate alternative to conventional visual synthetic methods. The technique was validated measuring pure CO2, and phase behaviour was then determined for two binary mixtures [CO2 (0.6) + CH4 (0.4)] and [CO2 (0.4) + CH4 (0.6)], results for which are presented. These systems are interesting for the study of biogas–like mixtures. In addition, data were compared with the equation of state used for natural gas GERG-2008, and also, they were modelled using Peng-Robinson equation of state and Wong- Sandler mixing rules, which are widely employed in chemical industries and which give good results., Trabajo financiado por el Ministerio de Industria, Economía y Competitividad (ENENE2013-47812-R y ENE2017-88474-R) y la Junta de Castilla y León (VA035U16 y VA280P18)

Vapor–liquid equilibrium data for the binary systems methyl acetate + 2-butanol and ethyl acetate+2-butanol, have been determined at 1.5 MPa employing a metal ebulliometer with recirculation of both phases. The thermodynamic consistency of experimental data has been verified with the Van Ness point-to-point test, using the routine in Fortran proposed by Fredenslund et al. in which the second and third virial coefficients were calculated using the Tsonopoulos method and the Orbey and Vera procedure, respectively. Different group contribution models were employed for prediction of high pressure data. The UNIFAC–Lyngby model returned good overall predictions. The ϕ–ϕ approach was applied using the perturbed-chain statistical associating fluid theory model. This equation of state produces an acceptable agreement between experimental and calculated data in both systems.