The Experts below are selected from a list of 147 Experts worldwide ranked by ideXlab platform
Dilip K Hazra - One of the best experts on this subject based on the ideXlab platform.
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ultrasonic velocities and isentropic compressibilities of electrolytes in 2 methoxyethanol from 15 to 35 c
Journal of Solution Chemistry, 2001Co-Authors: Pitchai J Victor, Bijan Das, Dilip K HazraAbstract:The ultrasonic velocities of lithium tetrafluoroborate (LiBF4), sodium tetrafluoroborate (NaBF4), tetraphenylphosphonium chloride (Ph4PCl), tetraphenylphosphonium bromide (Ph4PBr), and Tetraphenylarsonium chloride (Ph4AsCl) in 2-methoxyethanol (ME) have been measured at 15, 25, and 35°C. Apparent molar isentropic compressibilities κφ of these electrolytes were derived from these data supplemented with their densities. Infinite dilution partial molar compressibilities κφo were obtained by extrapolation from the plot of κφ vs. the square root of the molarity. The κφo values of the electrolytes were split into approximate limiting ionic compressibilities κφ±o on the basis of the assumption that κφo (BF−4) = 0. The results have been interpreted in terms of specific constitutional and structural factors of the solvent molecules and of solute ions.
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thermodynamics of ionic association of tetraphenylphosphonium Tetraphenylarsonium and some common cations in 2 methoxyethanol using conductometry and ft raman spectroscopy
Journal of Physical Chemistry B, 2000Co-Authors: Pitchai J Victor, Prakash K Muhuri, And Bijan Das, Dilip K HazraAbstract:Precise measurements on electrical conductances and Fourier Transform (FT) Raman spectra of solutions of Tetraphenylarsonium chloride (Ph4AsCl), tetraphenylphosphonium chloride (Ph4PCl), tetraphenylphosphonium bromide (Ph4PBr), lithium tetrafluoroborate (LiBF4), and sodium tetrafluoroborate (NaBF4) in 2-methoxyethanol (ME) at temperatures 288.15 ≤ T/K ≤ 308.15 are reported. The conductance data were analyzed by the 1978 Fuoss conductance−concentration equation. Thermodynamics of the association processes were also studied, and the Coulombic forces are found to play a major role in the association processes. The Raman spectra suggest the presence of “spectroscopically free” Cl-, Br-, and BF4- ions in solution, thus substantiating the moderate ion-pair formation constants for these electrolytes obtained from conductometric measurements. The observed processes were interpreted by an Eigen multistep mechanism. Raman spectra also indicate that the cations get attached to the ME molecules through the ethereal o...
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thermodynamics of ion association and solvation in 2 methoxyethanol behavior of Tetraphenylarsonium picrate and tetraphenylborate ions from conductivity and ultrasonic data
Journal of Physical Chemistry B, 1999Co-Authors: Pitchai J Victor, Prakash K Muhuri, And Bijan Das, Dilip K HazraAbstract:Precise measurements on electrical conductances and ultrasonic velocities of solutions of potassium picrate (KPic), potassium tetraphenylborate (KBPh4), tetrabutylammonium tetraphenylborate (Bu4NBP...
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solubilities of some alkali metal salts Tetraphenylarsonium chloride and tetraphenylphosphonium bromide in propylene carbonate at 25 degree c using the ion selective electrode technique
Journal of Chemical & Engineering Data, 1993Co-Authors: Prakash K Muhuri, Saroj K Ghosh, Dilip K HazraAbstract:The solubilities of 15 alkali-metal salts, MX (M + =Li, Na, K, Rb, and Cs; X - =Cl, Br, and ClO 4 ), Tetraphenylarsonium chloride, and tetraphenylphosphonium bromide are reported in propylene carbonate (PC) at 25 o C, and the free energies of solution for these electrolytes in this solvent have been determined. Combination of these values with solubility results in water yields the free energies of transfer of the electrolytes from water to propylene carbonate. Transfer activity coefficients for the electrolytes have also been computed from their solubility products in water and in the nonaqueous solvent
M Siroki - One of the best experts on this subject based on the ideXlab platform.
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extraction of 4 2 pyridylazo resorcinol and 4 2 thiazolylazo resorcinol with chloroform and Tetraphenylarsonium and phosphonium chlorides
Analytica Chimica Acta, 1996Co-Authors: Ljiljana Maric, M SirokiAbstract:Abstract The extraction of 4-(2-pyridylazo)resorcinol (PAR) and 4-(2-thiazolylazo)resorcinol (TAR) with chloroform alone and in the presence of Tetraphenylarsonium or tetraphenylphosphonium chloride (Ph 4 XCl) was studied. In the optimum pH range 3.5−5 for PAR and 1.5−5 for TAR, 94–95% of the reagents was extracted into chloroform. In the presence of Ph 4 XCl in 10–100-fold excess 95–98% of PAR and TAR were extracted within the pH range 3.5–10 and 1.5–10, respectively. The species extracted with chloroform alone were estimated to be H 2 R molecules. A quantitative interpretation of PAR and TAR distribution between aqueous solution (μ = 0.33) and chloroform was made. Distribution constants for H 2 R were determined as 14.9 for PAR and 19.2 for TAR. In the presence of Ph 4 XCl as extradant H 2 R molecules were predominantly extracted up to pH 4; between pH 4 and pH 8 two species H 2 R and Ph 4 X + HR − were transferred to the chloroform phase. Above pH 8 the Ph 4 X + HR − ion pairs were the only extracted species. They were studied in solution and by characterization of solid compounds isolated from the organic phase and aqueous solution.
G T Hefter - One of the best experts on this subject based on the ideXlab platform.
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thermodynamic properties of tetraphenylphosphonium perchlorate and Tetraphenylarsonium perchlorate from t 0 to t 340 k
The Journal of Chemical Thermodynamics, 2001Co-Authors: B V Lebedev, Yizhak Marcus, N N Smirnova, Ya L Tsvetkova, G T HefterAbstract:The temperature dependence of the standard molar heat capacity Cp,mo of samples of crystalline tetraphenylphosphonium perchlorate and Tetraphenylarsonium perchlorate was measured in an adiabatic low-pressure calorimeter between T = 4.8 K and T = 340 K and from T = 5.8 K to T = 340 K, respectively, mostly to within a precision of 0.2 per cent. For tetraphenylphosphonium perchlorate, an anomalous change of the heat capacity in the range T = 125 K to T = 185 K, probably arising from the excitation of hindered rotations of atomic groups, was found and its thermodynamic characteristics were determined. No such anomaly was observed for Tetraphenylarsonium perchlorate. The data obtained were used to calculate the thermodynamic functions Cp,mo(T)/R, Δ0THmo/R·K, Δ0TSmo/R, and φmo = Δ0TSmo - Δ0THmo/T (where R is the universal gas constant) of the compounds T → 0 and T = 340 K.
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application of the Tetraphenylarsonium tetraphenylborate tatb assumption to the hydration entropies of ions
The Journal of Chemical Thermodynamics, 2000Co-Authors: Yizhak Marcus, G T Hefter, Ting ChenAbstract:Abstract The hydration entropy of ions is calculated from their entropy in the ideal gaseous state and the standard entropy of their aqueous solutions. The application of the Tetraphenylarsonium tetraphenylborate (TATB) and the cognate tetraphenylphosphonium tetraphenylborate (TPTB) assumptions in obtaining the latter is explored, using newly determined heat capacity data for crystalline tetraphenyl phosphonium and arsonium perchlorates, their redetermined solubility data, both over a temperature interval, and data from the literature. The results are compared with those based on the widely accepted estimate of the standard entropy of the aqueous hydrogen ion based on thermocell data.
Yizhak Marcus - One of the best experts on this subject based on the ideXlab platform.
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thermodynamic properties of tetraphenylphosphonium perchlorate and Tetraphenylarsonium perchlorate from t 0 to t 340 k
The Journal of Chemical Thermodynamics, 2001Co-Authors: B V Lebedev, Yizhak Marcus, N N Smirnova, Ya L Tsvetkova, G T HefterAbstract:The temperature dependence of the standard molar heat capacity Cp,mo of samples of crystalline tetraphenylphosphonium perchlorate and Tetraphenylarsonium perchlorate was measured in an adiabatic low-pressure calorimeter between T = 4.8 K and T = 340 K and from T = 5.8 K to T = 340 K, respectively, mostly to within a precision of 0.2 per cent. For tetraphenylphosphonium perchlorate, an anomalous change of the heat capacity in the range T = 125 K to T = 185 K, probably arising from the excitation of hindered rotations of atomic groups, was found and its thermodynamic characteristics were determined. No such anomaly was observed for Tetraphenylarsonium perchlorate. The data obtained were used to calculate the thermodynamic functions Cp,mo(T)/R, Δ0THmo/R·K, Δ0TSmo/R, and φmo = Δ0TSmo - Δ0THmo/T (where R is the universal gas constant) of the compounds T → 0 and T = 340 K.
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application of the Tetraphenylarsonium tetraphenylborate tatb assumption to the hydration entropies of ions
The Journal of Chemical Thermodynamics, 2000Co-Authors: Yizhak Marcus, G T Hefter, Ting ChenAbstract:Abstract The hydration entropy of ions is calculated from their entropy in the ideal gaseous state and the standard entropy of their aqueous solutions. The application of the Tetraphenylarsonium tetraphenylborate (TATB) and the cognate tetraphenylphosphonium tetraphenylborate (TPTB) assumptions in obtaining the latter is explored, using newly determined heat capacity data for crystalline tetraphenyl phosphonium and arsonium perchlorates, their redetermined solubility data, both over a temperature interval, and data from the literature. The results are compared with those based on the widely accepted estimate of the standard entropy of the aqueous hydrogen ion based on thermocell data.
Ljiljana Maric - One of the best experts on this subject based on the ideXlab platform.
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extraction of 4 2 pyridylazo resorcinol and 4 2 thiazolylazo resorcinol with chloroform and Tetraphenylarsonium and phosphonium chlorides
Analytica Chimica Acta, 1996Co-Authors: Ljiljana Maric, M SirokiAbstract:Abstract The extraction of 4-(2-pyridylazo)resorcinol (PAR) and 4-(2-thiazolylazo)resorcinol (TAR) with chloroform alone and in the presence of Tetraphenylarsonium or tetraphenylphosphonium chloride (Ph 4 XCl) was studied. In the optimum pH range 3.5−5 for PAR and 1.5−5 for TAR, 94–95% of the reagents was extracted into chloroform. In the presence of Ph 4 XCl in 10–100-fold excess 95–98% of PAR and TAR were extracted within the pH range 3.5–10 and 1.5–10, respectively. The species extracted with chloroform alone were estimated to be H 2 R molecules. A quantitative interpretation of PAR and TAR distribution between aqueous solution (μ = 0.33) and chloroform was made. Distribution constants for H 2 R were determined as 14.9 for PAR and 19.2 for TAR. In the presence of Ph 4 XCl as extradant H 2 R molecules were predominantly extracted up to pH 4; between pH 4 and pH 8 two species H 2 R and Ph 4 X + HR − were transferred to the chloroform phase. Above pH 8 the Ph 4 X + HR − ion pairs were the only extracted species. They were studied in solution and by characterization of solid compounds isolated from the organic phase and aqueous solution.