Excess Enthalpies of Alkyl Formates + (n-Alkanes or 1-Chloroalkanes). Experimental Data and their Analysis in Terms of the UNIFAC Model

1989 ◽  
Vol 93 (6) ◽  
pp. 730-735 ◽  
Author(s):  
Juan Ortega
Keyword(s):  
Experimental Data ◽  
Excess Enthalpies ◽  
Unifac Model

Experimental data and modeling for excess enthalpies of 2-Pentanol with n-alkanes (C7–C9) at T = (293.15, 298.15 and 303.15) K

2020 ◽  
Vol 28 (6) ◽  
pp. 1661-1669
Author(s):  
Dongwei Wei ◽  
Mengying Li ◽  
Jing Ma ◽  
Baohe Wang
Keyword(s):  
Experimental Data ◽  
Excess Enthalpies

scholarly journals Optimizing Interaction Parameters of Various Thermodynamics Models using MATLAB to Estimate Activity Coefficients of Azeotropic Mixtures

2019 ◽  
Vol 9 (1) ◽  
pp. 379-384
Keyword(s):  
Experimental Data ◽  
Activity Coefficients ◽  
Interaction Parameters ◽  
General Interest ◽  
Equilibrium Conditions ◽  
Unifac Model ◽  
Azeotropic Mixtures ◽  
Conventional Models ◽  
Irregular Behavior ◽  
Vapor Phase Equilibrium

The calculation of the liquid-vapor phase equilibrium conditions in multicomponent mixtures is a subject of general interest for engineering. So in this article, interaction parameters of various thermodynamics models are optimized using MATLAB and the vapor-liquid equilibrium conditions are estimated through the application of the modified Raoult’s equation. Activity coefficients of azeotropic mixtures are also estimated. The application of conventional models is restricted for those systems that exhibit irregular behavior, that is, they form azeotropic. In these cases, the validity of these models is limited since the experimental data is not satisfactorily explained. The UNIFAC model completely explains the experimental data of non-ideal systems quite well.

scholarly journals Predictions of the vapor-liquid equilibrium data for low-GWP Hydrofluorocarbons + polyethylene-glycol dimethylether solvents by modified UNIFAC model

2021 ◽  
Vol 267 ◽  
pp. 02052
Author(s):  
Xiao Zhang ◽  
Liang Cai ◽  
Jingyi Qiao
Keyword(s):  
Experimental Data ◽  
Polyethylene Glycol ◽  
Large Deviations ◽  
Absorption Refrigeration ◽  
Refrigeration System ◽  
Liquid Equilibrium ◽  
Unifac Model ◽  
Equilibrium Data ◽  
Vle Data ◽  
Absorption Refrigeration System

The working fluids are crucial for developing the absorption refrigeration system. Our previous work has proposed three novel working pairs, which uses the low-GWP HFCs (R32, R152a and R161) as the refrigerants and the polyethylene-glycol dimethylether solvent DMETEG as the absorbent. To explore the VLE behaviors of HFCs in other longer chain structures of polyethylene-glycol dimethylether solvents, the modified UNIFAC (Dortmund) model was applied for prediction. The previous binary parameters showed large deviations from the experimental data. Then the new binary parameters were obtained by regression. For R32+DMEDEG and R152a/R161+DMETrEG, the prediction ARAD results were reduced from 17.13%, 24.06% and 12.48% to 3.71%, 2.61% and 6.86%, respectively. Finally, the VLE data of R161 + PGDE at the temperatures of 293.15-343.15K were predicted.

Measurements and Analysis of Excess Enthalpies of Ester + n-Alkane Using the UNIFAC Model

1991 ◽  
Vol 95 (2) ◽  
pp. 128-135 ◽  
Author(s):  
J. Ortega ◽  
J. L. Legido ◽  
J. Fernández ◽  
L. Pías ◽  
M. I. Paz Andrade
Keyword(s):  
Excess Enthalpies ◽  
Unifac Model

Excess enthalpies of aqueous solutions of biuret at 25 °C. Interaction with urea

1981 ◽  
Vol 59 (8) ◽  
pp. 1257-1260 ◽  
Author(s):  
Guido Barone ◽  
Pasquale Cacace ◽  
Giuseppina Castronuovo ◽  
Vittorio Elia
Keyword(s):  
Experimental Data ◽  
Aqueous Solutions ◽  
Empirical Relation ◽  
Interaction Coefficient ◽  
Excess Enthalpies ◽  
Flow Microcalorimetry ◽  
Heats Of Mixing ◽  
Heats Of Dilution ◽  
The Cross ◽  
First Time

The heats of dilution in water of biuret and the heats of mixing of biuret with urea have been determined by flow microcalorimetry at 25 °C. The excess enthalpies obtained from the experimental data can be expressed as virial expansions of the molalities.The value of the cross interaction coefficient hUB is compared to that calculated through the empirical relation hUB2 = (hUUhBB). The agreement between the two values outlines the strict analogy in the behaviour of these two solutes. The cited combining rule, verified up to now for pairs of solutes having both hii, hjj > 0, is here applied for the first time to a pair having hii, hjj < 0.

Correlation and prediction of excess enthalpies of ester + n-alkane systems using the UNIFAC model

1994 ◽  
Vol 240 ◽  
pp. 207-213 ◽  
Author(s):  
E. Siimer ◽  
L. Kudryavtseva
Keyword(s):  
Excess Enthalpies ◽  
Unifac Model
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