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Equation of state and structure in non-electrolyte liquids and their mixturesCostas Basin, Miguel Antonio January 1985 (has links)
No description available.
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The thermal conductivity of aqueous electrolyte solutions and polar liquidsBleazard, Joseph Gibson 12 1900 (has links)
No description available.
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Film boiling of binary mixtures.Yue, Po-lock. January 1971 (has links)
No description available.
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Thermodynamics of liquid mixtures : experimental and theoretical studies on the thermochemical and volumetric behaviour of some liquids and liquid mixtures.Govender, Ursula Penelope. January 1996 (has links)
The excess molar volumes VEm and the excess molar enthalpies HEm have been determined for several binary systems at 298.15 K using an Anton Paar Digital Densitometer and a 2277
Thermal Activity Monitor, respectively. VEm and HEm have been determined over the whole composition range for three types of binary mixtures involving hydrogen bonded interactions.
The three types are: (i) a short chain alkanol (methanol, ethanol, 1-propanol, 2-propanol) or (ii) a symmetrical secondary amine (di-n-ethylamine, di-n-propylamine) or (iii) 1-alkyne (l-hexyne, 1-heptyne, l-octyne) with a branched chain ether (diisopropyl ether, 1,1-dimethylethyl methyl ether, 1,1dimethylpropyl methyl ether) and a cyclic ether (tetrahydrofuran, tetrahydropyran, 1,4dioxane). For mixtures of (an alkanol + a branched chain ether or a cyclic ether) the results are explained in terms of the strong self association exhibited by the alkanol and the cross
association of the OH:::::O specific interaction. In particular for mixtures of (an alkanol + a cyclic ether) the results show trends relating to the size of the cycloether ring and the number
of carbon atoms in the alkanol molecule. For mixtures of a secondary amine + a branched chain ether or a cyclic ether the
experimental results have been explained on the basis of the strong molecular interactions (NH·····O) between the weakly self associating secondary amine and the ether oxygen. For binary mixtures of 1-alkyne + a branched chain ether the results indicate a dominance of the π....π interaction over either the dissociation effects of the 1-alkyne (π..... π interactions) or the breakdown of the branched chain ether molecules self association. Thermophysical property data, density p, cubic expansion coefficient ex and isothermal compressibility KT have also been determined for several aliphatic ethers from 288.15 K to
328.15 K at pressures ranging from 0.1 to 8 MPa. The molar volumes derived from the densities have been fitted to a polynomial as a function of temperature and pressure and the
second order thermodynamic functions, the cubic expansion coefficient ex and the isothermal compressibility KT determined. For all the ethers, the cubic expansion coefficients decrease
with an increase in temperature or pressure while the isothermal compressibilities increase with an increase in temperature or pressure over the temperature and pressure ranges investigated.
This work was carried out in the Thermodynamics laboratory of the Indian Institute of Technology in India. This data was required so that the experimental VEm and HEm data could be analyzed using modern theories of liquid mixtures. The VEm and HEm data presented here has been subjected to the following theoretical analysis: (i)The Extended Real Associated Solution (ERAS) model, (ii)The Modified Universal Functional Activity Coefficient (UNIFAC) group contribution model and (iii) The simple Flory and the Prigogine Flory Patterson theory (PFP). All the theories exhibited partial success when applied to the systems investigated here. Excess molar volumes and excess molar enthalpies, VEm and HEm have also been determined over the whole composition range for binary mixtures involving symmetrical (a straight chain ether or ketone + a pseudo straight chain ether or a pseudo straight chain ketone) to test the applicability of the congruency theory. Not all of the mixtures satisfied the null test of the congruency principle. / Thesis (Ph.D.)-University of Natal, 1996.
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Equation of state and structure in non-electrolyte liquids and their mixturesCostas Basin, Miguel Antonio January 1985 (has links)
Structural effects in hydrogen and non-hydrogen bonded liquids and their mixtures have been studied using several experimental techniques and theoretical approaches. Apparent heat capacities and volumes of linear alcohols in hydrocarbons were determined at very low alcohol concentrations and their self-association in solution discussed in terms of the Treszczanowicz-Kehiaian theory. An extension of this theory was used to describe cholesterol self-association and its interactions with tripalmitin and lecithin. Heat capacities of water-organic mixtures are reported. It is found that water behaves as a lower alcohol at the organic-rich concentration range. At the water-rich end, Shinoda's views on water structuring around hydrophobes are supported. Thermal pressure coefficients of cyclohexane + normal and branched alkanes are consistent with the presence of orientational order in the long pure n-alkanes. Excess volumes for mixtures of alkanes with liquids of different internal pressures are predicted using Flory theory. The anomalous thermodynamic behaviour of cyclopentane mixed with cyclic and branched alkanes has been studied through the measurement of cyclopentane spin-lattice relaxation times in these mixtures. An extension of Sanchez-Lacombe theory for pure liquids is described and the molecular parameters obtained for sixty common substances. An equation of state for pure n-alkanes with correlations of molecular orientations is presented.
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Film boiling of binary mixtures.Yue, Po-lock. January 1971 (has links)
No description available.
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Thermodynamics of liquid mixtures containing carboxylic acids.Redhi, Gyanasivan Govindsamy. January 2003 (has links)
The thesis involves a study of the thermodynamics of ternary liquid mixtures involving
carboxylic acids with nitriles, hydrocarbons including cycloalkanes, and water. Carboxylic
acids are an important class of compounds with a great number of industrial uses and
applications. In many parts ofthe world the separation of carboxylic acids (in particular acetic
and propanoic acid) is an important and desirable task. In South Africa, these carboxylic acids
together with many other oxygenates and hydrocarbons are produced by SASOL using the
Fischer - Tropsch process. The separation of these acids from hydrocarbons and from water
is a commercially lucrative consideration, and is the raison d' etre for this study. The work
focussed on the use of nitriles in effecting separation by solvent extraction and not by the
more common method of distillation. The nitrile compounds were chosen because of their
high polarity. The carboxylic acids used in this study always refer to: acetic acid, propanoic
acid, butanoic acid, 2-methylpropanoic acid, pentanoic acid and 3-methylbutanoic acid.
The first part of the experimental programme is devoted to the determination of excess molar
volumes of mixtures of (a carboxylic acid + nitrile compound), where the nitrile refers to
acetonitrile, butanenitrile or benzonitrile, respectively. Densimetry was used to determine the
excess molar volumes. The work was done in order to get some idea of the interactions
involved between a carboxylic acid and a nitrile.
The second part of the experimental study is concerned with the determination of excess
molar enthalpies of mixtures of( a carboxylic acid + nitrile compound), where the nitrile refers
to acetonitrile, butanenitrile or benzonitrile, respectively. The excess molar enthalpies were
determined using flow microcalorimetry Again, this work was done in order to gain some
insight into the interactions involved between a carboxylic acid and a nitrile.
The third part of the experimental work consists ofternary liquid-liquid equilibria of mixtures
of (acetonitrile + a carboxylic acid + heptane or cyclohexane), (benzonitrile + a carboxylic
acid + water); and (butanenitrile + a carboxylic acid + water), at 298.15 K. The purpose was
to investigate the use of nitriles as solvent extractors in separating carboxylic acids from
hydrocarbons and also carboxylic acids from water. Ternary liquid-liquid equilibrium data are essential for the design and selection of solvents used in the liquid-liquid extraction process.
The final section deals with the fitting of models of liquid mixtures to the experimental data
collected in this work. The NRTL (Non-random, two liquid), UNIQUAC (Universal quasichemical),
and FBT (Flory-Benson-Treszczanowicz) models were used. The modelling work
served three purposes:
• to summarise the experimental data
• to test theories of liquid mixtures
• prediction of related thermodynamic properties / Thesis (Ph.D.)-University of Natal,Durban, 2003.
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The critical properties and near-critical phase behavior of dilute mixturesGude, Michael Thomas 08 1900 (has links)
No description available.
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Thermodynamic investigations of some aqueous solutions through calorimetry and densimetryMarriott, Robert A., University of Lethbridge. Faculty of Arts and Science January 1999 (has links)
Relative densities and heat capacity ratios have been measured for selected aqueous systems. These measurements have been used to calculate apparent molar volumes and heat capacities. Densities of aqueous sodium bromide have been measured from 374 to 522 K and 10.00 to 30.00 MPa using a recently developed high temperature and pressure vibrating tube densimeter. These data have been used to test the utility of an automated high temperature and pressure densimetric data analysis program. Apparent molar volumes and heat capacities of several aqueous rare earth sulphate systems at 298.15 K and 0.10 MPa have been reported, and discussed in terms of ionic contributions. Single ion partial molar volumes and heat capacities for aqueous trivalent rare earth species have been estimated in a review of apparent molar data from the literature and through the use of semi-empirical Debye-Huckel equation. These singles ion properties have subsequently
been used to estimate the single ion properties of the monosulphate and disulphate rare earth complex species. Rigorous relaxation calculations are presented in a discussion of apparent molar heat capacities,
where relaxation contributions are shown to be negative. Apparent molar volumes and densities for aqueous L-histidine, L-phenylalanine, L-tyrosine, L-tryptophan, and L-dopa have been used to estimate reported
partial molar properties have been added to several reported properites for other amino acids and peptides to construct an additivity scheme that utilises the revised Helgeson, Kirkham, and Flowers (HKF) equations of state for neutral organic species. A volumetric study of aqueous glycine, L-serine, and glyclylglycine has been conducted at temperatures from 298 K to 423 K and pressures from 0.10 to 30.00 MPa. These data have been used to evaluate HKF coefficients in a discussion of peptide stability at elevated temperatures and pressures. / xvii, 220 leaves : ill. ; 28 cm.
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The thermodynamics of liquids in solution at 298 K and 1 atm.Naidoo, Rolandra D. January 2003 (has links)
For many years the problem of separating aliphatic and aromatic compounds has been at the
forefront of the petroleum and oil refining industries. This separation is often effected using
liquid-liquid extraction or extractive distillation. Both of these processes require the addition of a
solvent to bring about separation.
The aims of this work were to investigate the use of "mixed" solvents, such as those used in the
Arosolvan process, for their application in liquid-liquid extraction and extractive distillation as
well as to provide related thelmodynamic data for systems containing mixed solvents. In the last
part of this work, a computer program was developed to theoretically predict the effectiveness of
a number of solvents on a user-defined separation.
The solvents used for liquid-liquid extraction were chosen based on their similarities to those in
the Arosolvan process and were of the form, {N-methyl-2-pyrollidone (NMP) + glycerol, a glycol
or water} where the glycol was either monoethylene glycol (MEG), diethylene glycol (DEG) or
triethylene glycol (TEG). The additives were combined in various mixing ratios to NMP to
determine a mixing ratio for which the effect of the solvent is possibly optimized (a list of all
solvents and mixing ratios used are presented in this work).
Solvent selectivity and the range of compositions over which separation could occur determined
the effectiveness of the solvents. This work dealt with the separation of n-hexane and toluene. In
order to determine the selectivity and range of compositions, the liquid-liquid equilibria (LLE) of
systems containing n-hexane + toluene + solvent had to be determined. LLE was measured using
a simple equilibrium cell at 298 K and 1 atm. The phase separation boundaries (binodal curves)
were determined using a titration method.
The results obtained in this work showed an increase in the range of compositions over which the
mixture of n-hexane and toluene could be separated (i.e a larger range of mixing ratios over which
these components could be separated from each other) from the pure NMP solvent to the mixed
solvent cases. This implies that there is a The range of compositions over which separation could
be affected is given (for the solvents) in descending order:
NMP + 50% glycerol> NMP + 10% water > NMP + 30% MEG > NMP + 5% water > NMP +
30% glycerol> NMP + 10% glycerol > NMP + 10% MEG > NMP + 10% DEG > NMP + 10%
TEG > NMP + 5% DEG > 100% NMP.
The selectivities of the solvents showed a remarkable increase from the pure NMP case to the
mixed solvent cases. The maximum selectivity obtained for the NMP + 10% DEG system was
over 1200 compared to a maximum selectivity of just 6 for the pure NMP system. The maximum
selectivities obtained in descending order were as follows:
NMP + 10% DEG > NMP + 10% TEG > NMP + 10% glycerol > NMP + 10% MEG > NMP +
30% MEG > NMP + 50% glycerol > NMP + 10% water > NMP + 5% water > NMP + 30%
glycerol > NMP + 5% DEG > 100% NMP.
The binodal curves were modelled using the Hlavaty, ,8-density and log-y functions. The
maximum standard deviations obtained were 0.075, 0.078 and 0.05 for each of the functions
respectively. The equilibrium data was modelled using the UNIQUAC and NRTL
thermodynamic models and showed excellent agreement. This work showed better agreement to
the NRTL functions due to the fact that the non-randomness parameter, a ij , may be chosen
arbitrarily.
The results obtained in this work indicate that the use of mixed solvents greatly increases the
effectiveness ofNMP used for the separation of n-hexane and toluene. It is suggested that further
studies be performed on a wider range of aliphatic and aromatic compounds in order to determine
whether this is a generic behaviour or just true for n-hexane and toluene.
The effectiveness of each solvent for extractive distillation was determined by its separation
factor. In order to determine separation factors, the activity coefficients at infinite dilution
(IDACs) had to be measured. This was done using a gas-liquid chromatography technique. The
solvents employed in this study were NMP, Glycerol, MEG, TEG, NMP + 10% glycerol, NMP +
10% MEG, NMP + 10% DEG, NMP + 10% TEG. The solutes used were: pentane, heptane,
hexane, toluene and benzene.
The separation factors were determined for each alkane/aromatic pair per solvent. The pure
solvent cases were then compared to the mixed solvent cases. The mixed solvents did not show
results as promising for extractive distillation applications as they did for liquid-liquid extraction.
TEG displayed the best selectivities for each of the alkane/aromatic separations except for the
heptane/benzene pair, for which NMP + 10% glycerol proved to be the most effective solvent.
When compared to the results obtained from the original UNIF AC model, the IDACs obtained in
this work showed up to a 99% deviation. This is due to the fact that the model does not work well
for all types of molecules and does not predict the equilibrium of "unlike" molecules adequately.
It is suggested that other mixing ratios and different solvents be used to further investigate the
effectiveness of mixed solvents for extractive distillation applications. It is further recommended
that a computer aided data logging system be developed to determine residence times. This
would not only provide more accurate results, but also provide a database for future reference.
The computer program that was developed using the original UNIF AC method contains a
database of 28 commonly used industrial solvents. This program enables the user to compare
graphically the effectiveness of each of the solvents on the desired separation. Due to the
limitations of the original UNIF AC method, the program does not work well for all types of
molecules. However, the model can be changed without altering the prografnming structure to
include a modified version of the UNIFAC model depending on the users needs. The program
although written from an extractive distillation standpoint can be extended to include liquid-liquid
equilibrium predictions. The main benefit of such a program is to eliminate time-consuming
experimental work required to narrow down a long list of solvents required for a particular
separation by theoretically predicting the best solvents for the job. The solvent database can also
be expanded when new solvents become available or the user needs change / Thesis (M.Sc. Eng)-University of Natal, Durban, 2003.
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