Search results for "Thermodynamics"
showing 10 items of 2774 documents
Phase equilibria in the systems 3-methylpentane + methylcyclohexane, diisopropyl ether + methylcyclohexane and 3-methylpentane + diisopropyl ether + …
2002
Abstract Consistent vapor–liquid equilibria (VLE) at 101.3 kPa has been determined for the ternary system 3-methylpentane+diisopropyl ether (DIPE)+methylcyclohexane and the binary subsystems 3-methylpentane+methylcyclohexane and DIPE+methylcyclohexane in the temperature range from 336 to 374 K. According to the experimental results, the systems exhibit slight positive deviation from ideal behavior and no azeotrope is present. The VLE data have been correlated with the composition using the Wilson, UNIQUAC and NRTL relations. These models allow good prediction of the VLE properties of the ternary system from those of the pertinent binary subsystems.
Vapor–liquid equilibria in the ternary system isobutyl alcohol+isobutyl acetate+butyl propionate and the binary systems isobutyl alcohol+butyl propio…
2005
Abstract Consistent vapor–liquid equilibrium (VLE) data at 101.3 kPa have been determined for the ternary system isobutyl alcohol (IBA) + isobutyl acetate (IBAc) + butyl propionate (BUP) and two constituent binary systems: IBA + BUP and IBAc + BUP. The IBA + BUP system show lightly positive deviation from Raoult's law and IBAc + BUP system exhibits no deviation from ideal behaviour. The activity coefficients of the solutions were correlated with its composition by the Wilson, NRTL, UNIQUAC models. The ternary system is very well predicted from binary interaction parameters. BUP eliminates the IBA–IBAc binary azeotrope. The change of phase equilibria behaviour is significant therefore this s…
Vapor−Liquid Equilibria for the Binary Systems tert-Butyl Alcohol + Toluene, + Isooctane, and + Methylcyclohexane at 101.3 kPa
1998
Vapor-liquid equilibria were measured for binary systems of tert-butyl alcohol with toluene, isooctane, and methylcyclohexane at 101.3 kPa using a recirculating still. Experimental values of the vapor pressure of non-oxygenated pure components have been obtained. The accuracy of experimental measurements was ±0.01 K in temperature, ±0.01 kPa in pressure, and ±0.001 in mole fractions. The results are thermodynamically consistent according to the point-to-point consistency test. The data were correlated with five liquid-phase activity coefficients models (Margules, Van Laar, Wilson, NRTL, UNIQUAC).
Thermodynamic properties and conductivities of some dodecylsurfactants in water
1988
Densities, heat capacities, enthalpies of dilution, osmotic coefficients and conductivities are reported for dodecylamine hydrochloride, dodecyldimethylammonium and dodecyltrimethylammonium chloride in water over a wide range of concentration. The last two properties were also measured for dodecyltrimethylammonium bromide. From the thermodynamic data partial molar volumes, heat capacities and relative enthalpies and nonideal free energies and entropies were derived as a function of the surfactant concentration. The cmc's and degree of counterion dissociation were also calculated from the transport properties. It is shown that the trends of volumes, enthalpies, free energies and entropies ar…
Isobaric Vapor−Liquid Equilibria of Trichloroethylene with 1-Butanol and 2-Butanol at 20 and 100 kPa
1996
Vapor−liquid equilibria for trichloroethylene + 1-butanol, and + 2-butanol are reported at 20 and 100 kPa. The two systems satisfy the point-to-point thermodynamic consistency test. Both systems show a positive deviation from ideality.
Phase Equilibria Involved in Extractive Distillation of Dipropyl Ether + 1-Propyl Alcohol Using N,N-Dimethylformamide as Entrainer
2007
Consistent vapor−liquid equilibrium data for the binary and ternary systems dipropyl ether (1) + 1-propyl alcohol (2) + N,N-dimethylformamide (3) are reported at 101.3 kPa. The results indicate that dipropyl ether (1) + N,N-dimethylformamide (3) system exhibits a positive deviation from ideal behavior and that 1-propyl alcohol (2) + N,N-dimethylformamide (3) system deviates negatively from ideality. The activity coefficients of the solutions were correlated by the Wilson, NRTL, and UNIQUAC models. It is shown that these models allow a very good prediction of the phase equilibrium of the ternary system using the pertinent parameters of the binary systems. In addition, the Wisniak−Tamir relat…
Vapor−Liquid Equilibria for the Binary Systems Isobutanol with m-Xylene, o-Xylene and p-Xylene at 101.3 kPa
1999
Vapor−liquid equilibria were measured for binary systems of isobutanol with m-xylene, o-xylene, and p-xylene at 101.3 kPa using a recirculating still. The accuracy of experimental measurements was ±0.1 K in temperature, ±0.01 kPa in pressure, and ±0.001 in mole fraction. The results were determined to be thermodynamically consistent according to the point-to-point consistency and Wisniak tests. All the systems show moderate positive deviations from ideality. The data were correlated with five liquid-phase activity coefficient models (Margules, Van Laar, Wilson, NRTL, UNIQUAC).
Coordination properties of adenosine-5'-monophosphate and related ligands towards Me2Sn(IV)2+ in aqueous solution.
2002
Abstract The coordination of Me 2 Sn(IV) 2+ to adenosine-5′-monophosphate (AMP) and the related compounds d -ribose-5-phosphate (R5P), d -glucose-1-phosphate (G1P) and d -glucose-6-phosphate (G6P) in aqueous solution was investigated by means of potentiometric titration, and 1 H-, 31 P-NMR and Mossbauer spectroscopic methods in the pH range 2–11 ( I =0.1 M NaClO 4 , 298 K). The complex of AMP and Me 2 Sn(IV) 2+ precipitated at low pH was characterised by elemental analysis, FT-IR and Mossbauer spectroscopic methods. From a comparison of the p K values obtained in the presence and absence of metal ion and the stability constants for the different systems, the coordination of {N} is excluded,…
Inorganic Polyphosphates As Storage for and Generator of Metabolic Energy in the Extracellular Matrix.
2019
Inorganic polyphosphates (polyP) consist of linear chains of orthophosphate residues, linked by high-energy phosphoanhydride bonds. They are evolutionarily old biopolymers that are present from bacteria to man. No other molecule concentrates as much (bio)chemically usable energy as polyP. However, the function and metabolism of this long-neglected polymer are scarcely known, especially in higher eukaryotes. In recent years, interest in polyP experienced a renaissance, beginning with the discovery of polyP as phosphate source in bone mineralization. Later, two discoveries placed polyP into the focus of regenerative medicine applications. First, polyP shows morphogenetic activity, i.e., induc…
General application of Jäntti's method for the fast calculation of sorption equilibrium
2004
On the basis of a molecular model for adsorption kinetics Jantti introduced a method to calculate equilibriums shortly after a change of the pressure of the sorptive gas. In the present paper we show that this method is useful in many more situations than those intended originally.