Some difficulties on the application of the UNIFAC model for the prediction of liquid-liquid equilibrium compositions

UNIFAC group parameters for the interaction between CH2 and CF2 (c) and CH2 and CF3 were obtained using experimental liquid-liquid equilibrium data for hydrocarbon - perfluorodecaline (PFD) and hydrocarbon - perfluoromethylcyclohexane (PFMCH) systems. Some difficulties were experienced on the use of the UNIFAC method with those particular systems, namely the group parameters dependence on the length of the hydrocarbon chain. Attempts were made to correlate UNIFAC parameters with the number of carbon atoms and temperature and the results compared with those obtained with NRTL equations

Liquid-liquid equilibria of systems containing perfluoromethylcyclohexane

Liquidliquid equilibria for the quaternary system perfluoromethylcyclohexane (PFMCH)1-heptenen-heptanen-hexane at 288.15 K and for the ternary systems PFMCH1-heptenen-heptane, PFMCH1-heptenen-hexane and PFMCHn-heptanen-hexane at 279.15 K and 288.15 K are reported. The experimental results are compared with predicted values calculated using the NRTL and the UNIQUAC models

Perfluorodecalin/hydrocarbon systems prediction and correlation of liquid-liquid equilibrium data

Experimental binary, ternary and quaternary liquid-liquid equilibrium data for systems containing perfluorodecaline (PFD) and some hydrocarbons were determined. Binary NRTL, UNIQUAC and UNIFAC parameters were obtained, from the binary, the ternary and the quaternary experimental data: for the calculation of parameters from binary data a Newton-Raphson technique was used and the parameters so obtainedfor each temperature (T)-were linearly correlated with T and 1/T. Predicted binary, ternary and quaternary data were then compared with the experimental results; a Nelder-Mead method was used for the calculation of the binary parameters from ternary tie-line data. UNIFAC group parameters for the interaction CH2/CF2 and CH=CH2/CF2 were obtained. Attempts were made, and are discussed, to: correlate UNIFAC parameters with the number of carbon atoms and temperature; obtain a set of NRTL and UNIQUAC parameters yielding the overall best fit for the systems under consideration

Liquid-liquid equilibria for the system perfluorodecalin/1-heptene/n-heptane/n-hexane

Liquid-liquid equilibria for the quaternary system perfluorodecalln (PFD)/l-hepteneln-heptaneln-hexane at 288.15 K (type 111) and 298.15 K (type 11) and for the ternary systems PFDII-hepteneln-heptane, PFDII-hepteneln-hexane, and PFD/n -heptane/n-hexane at the same temperatures are reported. The experimental results are compared with values predicted by using the NRTL, the UNIQUAC, and the UNIFAC models

Mutual binary solubilities: perfluorodecalin/hydrocarbons

Mutual solublllty data for perfluorodecalln + n-hexane, + n-heptane, + noctane, + n-nonane, + 1-hexene, and + 1-heptene are reported. The NRTL and UNIOUAC equatlons were used to correlate the data. UNIFAC group parameters for the lnteractlons CH2/CF,( c) and CH=CHJCF,(c) can also be obtained

Mutual binary solubilities: perfluoromethylcyclohexane-hydrocarbons

Mutual binary solubility data for perfluoromethylcyclohexane+n-hexane, n-heptane, n-octane, n-nonane, 1-hexene and 1-heptene are reported. NRTL and UNIQUAC parameters, for each experimental temperature, were obtained using a NewtonRaphson technique and the parameters so obtained were linearly correlated with T and T1. UNIFAC group parameters for the interaction CH2/CF3 and CH=CH2/CF3 were obtained from mutual solubility data using the same technique. UNIFAC parameters were correlated with the number of carbon atoms and temperature

Vapor - liquid equilibrium of systems containing perfluoromethyl-cyclohexane and hydrocarbons

Vapor - liquid equilibrium data for the binary systems: Perfluoromethylcyclohexane + n-Hexane and Perfluoromethylcyclohexane + 1-Hexene were determined at 93.3 KPa and 328.15 K. The vapor pressure for the pure components were also measured to calculate the Antoine constants. The data were correlated by using the Van-Laar, Margules, Wilson, NRTL and UNIQUAC equations. UNIFAC group-contribution parameters between CH, and CF,, and CH,=CH and CF, were also calculated

El uso de fluidos supercríticos en la industria de aceites alimentarios

Residual olive oil extraction experiments were made with carbon dioxide under pressures of 12 and 15 MPa and 308.15, 313.15 and 318.15 K of temperature. We may conclude through the experiments, that under these pressures and temperature of 313.15 K there is no selected extraction of fatty acids, and higher recovery rates can be obtained in a short period of time.Se han realizado experiencias de extracción de aceite de orujo con dióxido de carbono a presiones de 12 y 15 MPa y a las temperaturas de 308.15, 313.15 y 318.15 K. Las pruebas efectuadas permiten concluir que en esta gama de presiones y a la temperatura de 313.15 K no existe extracción selectiva de los ácidos grasos y que se obtienen rendimientos elevados en relativamente poco tiempo

El uso de fluidos supercríticos en la industria de aceites alimentarios

Residual olive oil extraction experiments were made with carbon dioxide under pressures of 12 and 15 MPa and 308.15, 313.15 and 318.15 K of temperature.
 We may conclude through the experiments, that under these pressures and temperature of 313.15 K there is no selected extraction of fatty acids, and higher recovery rates can be obtained in a short period of time.<br><br>Se han realizado experiencias de extracción de aceite de orujo con dióxido de carbono a presiones de 12 y 15 MPa y a las temperaturas de 308.15, 313.15 y 318.15 K.
 Las pruebas efectuadas permiten concluir que en esta gama de presiones y a la temperatura de 313.15 K no existe extracción selectiva de los ácidos grasos y que se obtienen rendimientos elevados en relativamente poco tiempo

Extraction of value-added compounds from spent coffee grounds using supercritical fluid

In this work, supercritical fluid extraction (SFE) using carbon dioxide (CO2) as solvent was used for the recovery of antioxidant phenolic compounds and proteins from spent coffee grounds (SCG). Extraction assays were carried out under different conditions of temperature and pressure. The highest contents of flavonoids (164.57 mg QE/g extract), protein (160.97 mg BSA/g extract), and antioxidant activity (FRAP = 0.5843 mM Fe (II)/g extract; and total antioxidant capacity = 272.26 mg α-tocopherol/g extract) were obtained when using 250 bar and 333.15k. On the other hand, SFE at 200 bar and 313.15k was the best condition to recover phenolic compounds from SCG (33.63 mg GAE/g extract)