DISQUAC characterization of the carbonyl–oxygen interactions in binary liquid organic mixtures containing linear molecules: ketones and a monoether, diether, or triether

1996 ◽  
Vol 74 (10) ◽  
pp. 1815-1823 ◽  
Author(s):  
J.A. González ◽  
J.M. Fernández Martínez ◽  
I. García de la Fuente ◽  
J.C. Cobos
Keyword(s):  
Dipole Moments ◽  
Carbonyl Oxygen ◽  
Proximity Effects ◽  
Interaction Parameters ◽  
Good Representation ◽  
Model Interaction ◽  
Excess Gibbs Energies ◽  
Group Contribution Model ◽  
Linear Molecules ◽  
Oxygen Groups

The available data in the literature on vapour–liquid equilibria, excess Gibbs energies, and excess enthalpies for linear ketones + linear mono- or poly-ether mixtures are examined in terms of the DISQUAC group contribution model. Interaction parameters are reported. The quasichemical interchange coefficients are independent of the compounds in the systems; the dispersive interchange coefficients depend on the intramolecular environment of the carbonyl and (or) oxygen groups. Proximity effects, which seem to lead to an important increase of the interaction parameters, are briefly considered in treating systems including 1-methoxy-2-propanone or dimethyl carbonate molecules. DISQUAC consistently describes the experimental data of the mixtures investigated. The rather good representation obtained for vapour–liquid equilibria at high temperatures is noteworthy. A discussion in terms of effective and reduced dipole moments of binary mixtures containing carbonyl and oxygen groups in the same or different molecules is also presented. Key words: liquids, mixtures, thermodynamics, dipole moments, group contributions.

Thermodynamics of mixtures with strongly negative deviations from Raoult's law. Part 3. Application of the DISQUAC model to mixtures of triethylamine with alkanols. Comparison with Dortmund UNIFAC and ERAS results

2000 ◽  
Vol 78 (10) ◽  
pp. 1272-1284 ◽  
Author(s):  
Juan Antonio González ◽  
Isaias Garcia de la Fuente ◽  
Jose Carlos Cobos
Keyword(s):  
Constant Pressure ◽  
Dipole Moments ◽  
Interaction Parameters ◽  
Short Discussion ◽  
Molar Excess ◽  
Gibbs Energies ◽  
Excess Gibbs Energies ◽  
Specific Parameter ◽  
Thermodynamics Of Mixtures ◽  
Vapor Liquid Equilibria

Binary mixtures of triethylamine (TEA) and alkanols have been investigated in the framework of DISQUAC. The systems are built by three contacts: aliphatic–hydroxyl, aliphatic–nitrogen, and hydroxyl–nitrogen. The corresponding interaction parameters are reported and discussed. The former are avalilable in the literature but were modified (particularly the third dispersive (DIS) and quasichemical (QUAC) interchange coefficients) for sec- and tert-alkanols + n-alkanes using recent data on excess heat capacities at constant pressure (CEP) for systems of these alkanols with n-heptane. The interaction parameters for aliphatic-nitrogen contacts are purely dispersive. The structure dependence of the DIS and QUAC interchange coefficients of the hydroxyl-nitrogen contacts in 1-alkanols + TEA systems is similar to that found in other solutions previously investigated. The QUAC interchange coefficients remain constant from ethanol and are also valid for 2-alkanols and tert-butanol. Methanol behaves differently. A short discussion in terms of effective dipole moments is also included. DISQUAC represents well the thermodynamic properties examined: vapor-liquid equilibria (VLE), molar excess Gibbs energies (GE) and molar excess enthalpies (HE). DISQUAC provides better results than the Dortmund version of UNIFAC using the published geometrical and interaction parameters. ERAS parameters for 1-alkanols + TEA systems are also reported. Interactions between unlike molecules are stronger for solutions with methanol or ethanol. DISQUAC improves ERAS results on HE, while both models give similar results for GE. However, ERAS needs an specific parameter, with unknown temperature-dependence, to describe properly GE. The main advantage of ERAS is its ability to provide information on VE. Its main limitation is that can be only applied to those systems where association is expected. DISQUAC, a purely physical model, can be applied to any type of binary mixture, as it is followed from this and previous studies.Key words: theory, liquids, associated, thermodynamics, group contributions.

Conformation and electronic structure of aromatic chloroformates

1987 ◽  
Vol 52 (4) ◽  
pp. 970-979 ◽  
Author(s):  
Otto Exner ◽  
Pavel Fiedler
Keyword(s):  
Electronic Structure ◽  
Oxygen Atom ◽  
Strong Interaction ◽  
Electron Distribution ◽  
Room Temperature ◽  
Functional Group ◽  
Dipole Moments ◽  
Carbonyl Oxygen ◽  
Nonpolar Solvents ◽  
Single Method

Aromatic chloroformates Ib-Ie were shown to exist in the ap conformation, in agreement with aliphatic chloroformates, i.e. the alkyl group is situated cis to the carbonyl oxygen atom as it is the case in all esters. While 4-nitrophenyl chloroformate (Ie) is in this conformation in crystal, in solution at most several tenths of percent of the sp conformation may be populated at room temperature and in nonpolar solvents only. A new analysis of dipole moments explained the previous puzzling results and demonstrated the impossibility to determine the conformation by this single method, in consequence of the strong interaction of adjoining bonds. If, however, the ap conformation is once proven, the dipole moments reveal some features of the electron distribution on the functional group, characterized by the enhanced polarity of the C-Cl bond and reduced polarity of the C=O bond. This is in agreement with the observed bond lengths and angles.

scholarly journals Application of COSMO-RS Method for the Prediction of Liquid-Liquid Equilibrium of Water/n-Dodecane/1-Butanol

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
S. Balasubramonian ◽  
Shekhar Kumar ◽  
D. Sivakumar ◽  
U. Kamachi Mudali
Keyword(s):  
Activity Coefficient ◽  
Mutual Solubility ◽  
Solubility Data ◽  
Interaction Parameters ◽  
Binary Interaction ◽  
Liquid Equilibrium ◽  
Model Interaction ◽  
Uniquac Model ◽  
Unifac Model ◽  
Lle Data

The liquid-liquid equilibrium (LLE) for the system water-dodecane-butanol was estimated using the UNIQUAC model. In the UNIQUAC model interaction parameters were estimated from the vapor-liquid equilibrium (VLE) and LLE data of their constituent binary pairs. The water-dodecane-butanol LLE was experimentally measured at 298.15 K. Phase stability constraints were taken into account while calculating the binary interaction parameters from the mutual solubility data. The COSMO-RS method was used to estimate the activity coefficient in the miscible binary pair. The ternary LLE composition was predicted using the experimental VLE data as well as using the COSMO-RS calculated activity coefficient data along with the experimental mutual solubility data. In the latter case the root mean square deviation (RMSD) for the distribution of butanol between aqueous and organic phase is 0.24%. The corresponding UNIFAC model prediction is 7.63%.

Evaluation of the Carbonyl/Chlorine Interaction Parameters in Pentan-3-one-Chloroalkane Mixtures Using the Disquac Group Contribution Model

2000 ◽  
Vol 65 (10) ◽  
pp. 1559-1572 ◽  
Author(s):  
Mariana Teodorescu ◽  
Ivan Wichterle
Keyword(s):  
Experimental Data ◽  
Chain Length ◽  
Group Contribution ◽  
Interaction Parameters ◽  
Liquid Equilibrium ◽  
Disquac Model ◽  
Thermodynamic Behaviour ◽  
Consistent Description ◽  
Group Contribution Model

Thermodynamic behaviour of the eight systems containing pentan-3-one and a chloroalkane, namely 1-chlorobutane, 1,2-dichloroethane, 1,3-dichloropropane, 1,4-dichlorobutane, trichloromethane, 1,1,1-trichloroethane, tetrachloromethane and 1,1,2,2-tetrachloro- ethane was interpreted in terms of the DISQUAC group contribution model. It was found that quasichemical term for the contact C=O/Cl in the pentan-3-one-α,ω-dichloroalkane and pentan-3-one-1,1,1-trichloroethane systems is not negligible. The DISQUAC dispersive interchange parameters for C=O/Cl contact in these systems were evaluated from literature data on linear ketone + 1-chloroalkane systems. It was found that the best description of experimental data for systems containing 1-chlorobutane, trichloromethane, tetrachloromethane, and 1,1,2,2-tetrachloroethane is provided using only dispersive contribution of the C=O/Cl contact. The vapour-liquid equilibrium, GE, and HE data were calculated using the DISQUAC model and compared with experimental data. The model provides a fairly consistent description. The relation between the DISQUAC interchange parameters for C=O/Cl contact and the chloroalkane chain length was established.

scholarly journals Surface properties of some carotenoids spread in monolayers at the air/water interface. Experimental and computational approach

2006 ◽  
Vol 4 (3) ◽  
pp. 489-501
Author(s):  
Ossi Horovitz ◽  
Gheorghe Tomoaia ◽  
Csaba Racz ◽  
Aurora Mocanu ◽  
Liviu-Dorel Bobos ◽  
...  
Keyword(s):  
Surface Properties ◽  
Dipole Moments ◽  
State Equation ◽  
Interaction Parameters ◽  
Water Interface ◽  
Molecular Area ◽  
Collapse Pressure ◽  
Pressure Surface ◽  
Air Water Interface ◽  
Β Carotene

AbstractThe surface pressure versus molecular area isotherms of some carotenoids: β,β-carotene-4-one (echinenone, ECH), β,β-carotene-4,4′-dione (canthaxanthin, CAN) and 4,4′-diapo-ω,ω-carotene-4,4′-dial (APO), spread at the air/water interface, are reported. A van der Waals type state equation is used to describe the high molecular area portions of the compression isotherms and interaction parameters within monolayers are derived. Quantum chemical semi-empirical SCF MO calculations (AM1 and PM3) are performed for the optimized geometries of molecules and dipole moments are calculated. Similar theoretical magnitudes are obtained by both methods. Surface properties, like collapse pressure, surface compressional modulus and interaction parameters are discussed in terms of dipole-dipole interactions, and correlations with the calculated quantities for the carotenoid molecules are analyzed. The orientation of the different carotenoid molecules in the monolayer is discussed.

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