Solubility, enthalpy, and heat capacity of solution of tris(2,4-pentanedionato)cobalt(III) in aqueous mixed solvents of 2-butoxyethanol and 2-ethoxyethanol

1989 ◽  
Vol 67 (12) ◽  
pp. 2108-2115 ◽  
Author(s):  
Yasuki Yoshimura
Keyword(s):  
Heat Capacity ◽  
Linear Correlation ◽  
Composition Dependence ◽  
Enthalpy Of Solution ◽  
Excess Enthalpy ◽  
Mixed Solvents ◽  
The Other ◽  
Aqueous Mixtures ◽  
Heat Capacity Of Solution ◽  
Excess Internal Pressure

The solubility in mole fraction Xs of tris(2,4-pentanedionato)cobalt(III) (Co(acac)3) in aqueous mixtures of 2-butoxyethanol (BE) and 2-ethoxyethanol (EE) has been determined over the temperature range 5–50 °C. From these data, the enthalpy [Formula: see text] and heat capacity of solution [Formula: see text] of Co(acac)3 are estimated by using the Clarke and Glew procedure. For the water–BE system, an approximately linear correlation is found between the excess enthalpy of solution [Formula: see text] of Co(acac)3 and the excess internal pressure δPi of the mixtures at 25 °C. This finding suggests that the composition dependence of [Formula: see text] in this system is mostly governed by the composition dependence of Pi. On the other hand, [Formula: see text] in these mixtures exhibits a characteristic composition dependence and its composition dependence in the water–BE mixtures may be qualitatively explained by considering an effect of the microphase transition which has been shown to occur in the mixture. The composition dependence of both [Formula: see text] and [Formula: see text] in the water–BE mixture is analogous to that in the water–BE mixture and this finding suggests that a microphase formation may also occur in the former mixture. Keywords: tris(2,4-pentanedionato)cobalt(III), temperature dependence of solubility, enthalpy and heat capacity of solution, aqueous mixtures of 2-butoxyethanol and 2-ethoxyethanol, microphase transition.

Enthalpy of solution of tris(2,4-pentanedionato)cobalt(III) in aqueous mixed solvents of 1,4-dioxane and 2-methyl-2-propanol

1987 ◽  
Vol 65 (6) ◽  
pp. 1218-1223 ◽  
Author(s):  
Yasuki Yoshimura
Keyword(s):  
Internal Pressure ◽  
Mole Fraction ◽  
Linear Correlation ◽  
Composition Dependence ◽  
Enthalpy Of Solution ◽  
Excess Enthalpy ◽  
Mixed Solvents ◽  
Hydrophobic Hydration ◽  
System A ◽  
Excess Internal Pressure

The solubilities Xs of tris(2,4-pentanedionato)cobalt(III) (Co(acac)3) in water – 1,4-dioxane (D) and water – 2-methyl-2-propanol (TBA) mixtures were determined over the temperature range of 15–60 °C and 20–43 °C, respectively. These data were fitted to [Formula: see text] and the enthalpy of solution [Formula: see text] of Co(acac)3 was estimated by differentiating the equation. For the water–D system, a linear correlation was found between the excess enthalpy of solution [Formula: see text] of Co(acac)3 and the excess internal pressure [Formula: see text] of the mixtures. [Formula: see text] of Co(acac)3 in the water–TBA mixtures showed complicated composition dependence due to microheterogeneity in the mixtures. The enthalpy of hydrophobic hydration [Formula: see text] of Co(acac)3 in the water–D mixtures was also estimated from the solubility curves and it was found that [Formula: see text] decreased exponentially with decreasing mole fraction of water.

The enthalpies of solution of Hexa-1-ol and Heptan-1-ol in water

1974 ◽  
Vol 27 (9) ◽  
pp. 1905 ◽  
Author(s):  
DJT Hill ◽  
LR White
Keyword(s):  
Heat Capacity ◽  
Free Energy ◽  
Thermodynamic Function ◽  
Homologous Series ◽  
The Other ◽  
Enthalpies Of Solution ◽  
Calorimetric Measurement ◽  
Temperature Range ◽  
Heat Capacity Of Solution

The solubility of hexan-1-ol and heptan-1-ol in water has been measured over the temperature range 278-308 K. The free energy, enthalpy and heat capacity of solution of these alcohols has been calculated from this data and the enthalpy and heat capacity have also been obtained by direct calorimetric measurement. The thermodynamic function changes on solution of these two alcohols follow the pattern of the lower members of the homologous series. The results have been compared qualitatively with data for the other alcohols and for the hydrocarbons.

On Temperature Dependence of Excess Gibbs Energy

1999 ◽  
Vol 64 (7) ◽  
pp. 1093-1099 ◽  
Author(s):  
Ivona Malijevská ◽  
Anatol Malijevský
Keyword(s):  
Heat Capacity ◽  
Gibbs Energy ◽  
Temperature Dependence ◽  
Excess Gibbs Energy ◽  
Excess Enthalpy ◽  
Excess Heat Capacity ◽  
Wilson Equation ◽  
Excess Heat ◽  
Energy Excess ◽  
Wilson And Nrtl Equations

Temperature dependence of GE is discussed for three widely used equations linear and nonlinear in parameters. It is shown that the Wilson equation predicts always positive excess heat capacity regardless of values of its parameters. Several temperature modifications of the Redlich-Kister, Wilson and NRTL equations are discussed with respect to the sign of the excess Gibbs energy, excess enthalpy and excess heat capacity.

Transfer Thermodynamic Functions ∆Gt0, ∆Ht0 and T∆St0 of cis- and trans-[CoCl2(en)2]+ Isomers in Aqueous Mixtures of Methanol, tert-Butyl Alcohol and Acetonitrile

2000 ◽  
Vol 65 (9) ◽  
pp. 1455-1463
Author(s):  
Oľga Vollárová ◽  
Ján Benko
Keyword(s):  
Enthalpy Of Solution ◽  
Transfer Functions ◽  
Partial Molar Volumes ◽  
Butyl Alcohol ◽  
Aqueous Mixtures ◽  
Aqueous Methanol ◽  
Solvent Interactions ◽  
Tert Butyl Alcohol ◽  
Surface Charge Distribution ◽  
Cis And Trans

The solubility, partial molar volume and standard integral molar enthalpy of solution of cis- and trans-[CoCl2(en)2]Cl in water, aqueous methanol, aqueous tert-butyl alcohol and aqueous acetonitrile are reported. The transfer functions ∆Gt0, ∆Ht0 and T∆St0 as well as partial molar volumes are used to obtain information on the solute-solvent interactions. Results obtained are discussed in terms of differences in the surface charge distribution in isomeric coordination species.

Electron-transfer reactions in non-aqueous media. VII. Reduction of CoF(NH3)52+ and Co(HCOO)(NH3)52+ by copper(I) in dimethyl sulfoxide-water mixtures

1983 ◽  
Vol 36 (10) ◽  
pp. 1923 ◽  
Author(s):  
JMB Harrowfield ◽  
L Spiccia ◽  
DW Watts
Keyword(s):  
Electron Transfer ◽  
Dimethyl Sulfoxide ◽  
Aqueous Media ◽  
Mixed Solvents ◽  
Transfer Reactions ◽  
Aprotic Solvents ◽  
Aqueous Mixtures ◽  
Electron Transfer Reactions ◽  
Dipolar Aprotic Solvents ◽  
Sphere Mechanism

Previous work on the reduction of a series of cobalt(III) complexes by iron(II) in dipolar aprotic solvents and in aqueous mixtures has been extended to reduction by copper(I). The greater stability of copper(I) to disproportionation in these media has permitted the study of the reduction of CoF(NH3)52+ and Co(HCOO)(NH3)52+ in range of solvents over a number of temperatures with a precision not possible in previous studies in water. The results are consistent with an inner-sphere mechanism in which the copper(I) reductant is preferentially solvated by dimethyl sulfoxide to the exclusion of water in mixed solvents.

scholarly journals Lipid composition of the brains of she-goat and castrated goat consumed in Ekiti State, Nigeria

2015 ◽  
Vol 50 (2) ◽  
pp. 153-162 ◽  
Author(s):  
EI Adeyeye ◽  
AJ Adesina
Keyword(s):  
Fatty Acids ◽  
Gas Chromatography ◽  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Linear Correlation ◽  
The Other ◽  
A Value ◽  
Significant Difference ◽  
Value Range ◽  
Goat Brain

The levels of fatty acids, phospholipids and sterols were determined in the brains of she-goat and castrated goat found in Ekiti State, Nigeria by gas chromatography. Results showed that the crude fat levels were 9.98 and 10.2 % in the brains of she-goat and castrated goat respectively. The fatty acid composition of she-goat and castrated goat brain shows that the SFA was 40.6 and 42.7 %, MUFA was 37.1 and 38.7 % and PUFA was 20.9 and 22.3% respectively. The other parameters of she-goat and castrated goat brain were found: PUFA/SFA, 0.490 and 0.548; MUFA/SFA, 0.869 and 0.953; n-6/n-3, 0.775 and 11.7; LA/ALA, 0.876 and 28.0; AA/DGLA, 6.05 and 17.4; EPA/DHA, 1.00 and 5.89 and EPSI (PUFA/MUFA), 0.564 and 0.575 respectively. Phospholipids were present in she-goat and castrated goat with a value range of 2365 and 3047 mg/100g respectively. Among the sterols, only cholesterol was of any significant level with values of 1353 mg/100g (she-goat brain) and 1355 mg/100g (castrated goat brain). Linear correlation at ? = 0.05, df: n-1 showed that no significant difference exists between the crude fats, phospholipids and sterols except in the fatty acids parameters.Bangladesh J. Sci. Ind. Res. 50(2), 153-162, 2015

scholarly journals The validation of quantum chemical lipophilicity prediction of alcohols

2016 ◽  
Vol 9 (2) ◽  
pp. 89-94 ◽  
Author(s):  
Martin Michalík ◽  
Vladimír Lukeš
Keyword(s):  
Linear Correlation ◽  
Quantum Chemical ◽  
Partition Coefficients ◽  
The Other ◽  
Basis Set ◽  
Implicit Solvent ◽  
Solvent Models ◽  
Lipophilicity Prediction ◽  
Triple Zeta ◽  
Implicit Solvent Models

AbstractThe validation of octanol-water partition coefficients (logP) quantum chemical calculations is presented for 27 alkane alcohols. The chemical accuracy of predicted logPvalues was estimated for six DFT functionals (B3LYP, PBE0, M06-2X, ωB97X-D, B97-D3, M11) and three implicit solvent models. Triple-zeta basis set 6-311++G(d,p) was employed. The best linear correlation with the experimental logPvalues was achieved for the B3LYP and B97-D3 functionals combined with the SMD model. On the other hand, no linearity was found when IEF-PCM or C-PCM implicit models were employed.

Minimum Irreversibility Criteria for Heat Exchanger Configurations

1999 ◽  
Vol 121 (4) ◽  
pp. 241-246 ◽  
Author(s):  
F. E. M. Saboya ◽  
C. E. S. M. da Costa
Keyword(s):  
Heat Capacity ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
Cross Flow ◽  
Second Law Of Thermodynamics ◽  
The Other ◽  
Maximum Heat ◽  
Transfer Rates ◽  
Mass Flow Rates ◽  
Flow Heat

From the second law of thermodynamics, the concepts of irreversibility, entropy generation, and availability are applied to counterflow, parallel-flow, and cross-flow heat exchangers. In the case of the Cross-flow configuration, there are four types of heat exchangers: I) both fluids unmixed, 2) both fluids mixed, 3) fluid of maximum heat capacity rate mixed and the other unmixed, 4) fluid of minimum heat capacity rate mixed and the other unmixed. In the analysis, the heat exchangers are assumed to have a negligible pressure drop irreversibility. The Counterflow heat exchanger is compared with the other five heat exchanger types and the comparison will indicate which one has the minimum irreversibility rate. In this comparison, only the exit temperatures and the heat transfer rates of the heat exchangers are different. The other conditions (inlet temperatures, mass flow rates, number of transfer units) and the working fluids are the same in the heat exchangers.

SODIUM, POTASSIUM, AND LACTIC ACID AFTER MUSCULAR EXERCISE IN THE RAT

1958 ◽  
Vol 36 (1) ◽  
pp. 1193-1201
Author(s):  
F. A. Sréter ◽  
Sydney M. Friedman
Keyword(s):  
Lactic Acid ◽  
Blood Sugar ◽  
Linear Correlation ◽  
The Other ◽  
Muscular Exercise ◽  
Sodium Potassium ◽  
Standard Time ◽  
Old Rats ◽  
Severe Exercise ◽  
Definite Correlation

Untrained young rats were exercised on a treadmill for a standard time at different speeds. A linear correlation between the intensity of the exercise and the degree of plasma [K] rise was observed. On the other hand, exercise at standard speed for varying durations was found to cause an increase in plasma [K] only during the early stages of the exercise. A fall in plasma [Na] was a constant accompaniment of exercise but no definite correlation to either intensity or duration was found. Lactic acid rose only with relatively severe exercise or with excitement. Blood sugar did not vary. Old rats responded to even mild exercise with a marked [K] shift accompanied by a well-defined rise in lactic acid.

scholarly journals Verdampfungsgleichgewicht und thermodynamisehe Funktionen des flüssigen Systems Wasser + Essigsäure / Vapour-Liquid. Equilibrium and Thermodynamic Functions of the Liquid System Water + Acetic Acid

1973 ◽  
Vol 28 (10) ◽  
pp. 1740-1742 ◽  
Author(s):  
R. Haase ◽  
M. Pehlke ◽  
K.-H. Dücker
Keyword(s):  
Acetic Acid ◽  
Composition Dependence ◽  
Excess Enthalpy ◽  
Excess Entropy ◽  
Liquid System ◽  
Gibbs Function ◽  
Liquid Equilibrium ◽  
Molar Excess ◽  
C 30 ◽  
System Water

Vapour pressures and vapour compositions of the liquid system water + acetic acid have been measured at 25 °C, 30 °C, 35 °C, 40 °C, and 45 °C in the whole range of compositions. The dimerization of acetic acid in the vapour being taken into account, the molar excess Gibbs function ḠE is derived from the measurements. Earlier measurements of the molar excess enthalpy HE are combined with the -GE values to give the molar excess entropy SE. The “symmetry rule” (Haase, 1951) concerning the composition dependence of ḠE, -HE, and S̄E has been confirmed.

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