The Experts below are selected from a list of 192 Experts worldwide ranked by ideXlab platform
Evgeniy V. Ivanov - One of the best experts on this subject based on the ideXlab platform.
-
solutions of urea and Tetramethylurea in formamide and water a comparative analysis of volume characteristics and solute solute interaction parameters at temperatures from 288 15 to 328 15 k and ambient pressure
Journal of Chemical & Engineering Data, 2019Co-Authors: Evgeniy V. Ivanov, Andrey V. Kustov, Elena Yu. LebedevaAbstract:Densities of urea (U) and Tetramethylurea (TMU) solutions in formamide (FA) and water with a solute molality of up to ∼2 mol kg–1 were measured at T = 288.15, 298.15, 308.15, 318.15, and 328.15 K a...
-
Solutions of Urea and Tetramethylurea in Formamide and Water: A Comparative Analysis of Volume Characteristics and Solute–Solute Interaction Parameters at Temperatures from 288.15 to 328.15 K and Ambient Pressure
Journal of Chemical & Engineering Data, 2019Co-Authors: Evgeniy V. Ivanov, Andrey V. Kustov, Elena Yu. LebedevaAbstract:Densities of urea (U) and Tetramethylurea (TMU) solutions in formamide (FA) and water with a solute molality of up to ∼2 mol kg–1 were measured at T = 288.15, 298.15, 308.15, 318.15, and 328.15 K a...
-
d2o h2o solvent isotope effects on the enthalpy of 1 1 3 3 Tetramethylurea hydration between 278 15 and 318 15 k
Thermochimica Acta, 2010Co-Authors: Dmitriy V Batov, Evgeniy V. IvanovAbstract:Abstract The enthalpies of solution of 1,1,3,3-Tetramethylurea in H2O and D2O were measured at 278.15, 288.15, 298.15, 308.15, and 318.15 K. Standard enthalpies and heat capacities of solution (hydration), along with D2O–H2O solvent isotope effects on the quantities studied, were computed. The enthalpies of the solute dissolution as well as corresponding solvent isotope effects were found to be negative in sign and decreasing in magnitude with increasing temperature. It was confirmed that hydrophobic hydration is the predominant type of the solute hydration and it is enhanced in D2O and weakened on going from 1,1,3,3-Tetramethylurea to its cyclic derivative, 1,3-dimethyl-2-imidazolidinone.
-
Effect of intramolecular cyclization on the enthalpies of solvation of Tetramethylurea in water and alkanols at 298.15 K
Thermochimica Acta, 2008Co-Authors: Evgeniy V. Ivanov, Valeriy I. Smirnov, Vladimir K. AbrosimovAbstract:Abstract The enthalpies of solution of N , N ′-dimethylethyleneurea (1,3-dimethyl-2-imidazolidinone) in water, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, and t -butanol (2-methyl-2-propanol) were measured calorimetrically at 298.15 K. For comparison purposes, the previous data on enthalpic effects of 1,1,3,3-Tetramethylurea dissolution (solvation) in the same solvents were analyzed. It has been concluded that the intramolecular cyclization of Tetramethylurea, to form dimethylethyleneurea, results in strengthening of the solute solvation and this tendency is more pronounced in a non-aqueous (alcoholic) medium.
-
Enthalpies of solution of N,N,N',N'-Tetramethylurea in amides, dimethylsulphoxide, and acetone at 298.15 K
The Journal of Chemical Thermodynamics, 2008Co-Authors: Evgeniy V. Ivanov, Valeriy I. SmirnovAbstract:The enthalpies of solution Δ sol H m m were determined for N , N , N ′, N ′-Tetramethylurea in formamide, N -methylformamide, N,N -dimethylformamide, N,N -dimethylacetamide, dimethylsulphoxide, and acetone. Measurements were made at 298.15 K and molalities m = (0.004 to 0.031) mol · kg −1 with a precise isoperibol ampoule-type calorimeter. Standard enthalpies of solution Δ sol H m ∘ and transfer Δ tr H m ∘ from one solvent to another were computed. The enthalpies of solution of the solute in the hydrogen-non-bonding media were found to be endothermic and weak depending on the nature of methylation in a solvent molecule. It was concluded that the solvent proton-donor ability and existing steric hindrances for hydrogen bonding and other intermolecular interactions play the key role in solvation of Tetramethylurea.
Elena Yu. Lebedeva - One of the best experts on this subject based on the ideXlab platform.
-
Solutions of Urea and Tetramethylurea in Formamide and Water: A Comparative Analysis of Volume Characteristics and Solute–Solute Interaction Parameters at Temperatures from 288.15 to 328.15 K and Ambient Pressure
Journal of Chemical & Engineering Data, 2019Co-Authors: Evgeniy V. Ivanov, Andrey V. Kustov, Elena Yu. LebedevaAbstract:Densities of urea (U) and Tetramethylurea (TMU) solutions in formamide (FA) and water with a solute molality of up to ∼2 mol kg–1 were measured at T = 288.15, 298.15, 308.15, 318.15, and 328.15 K a...
-
solutions of urea and Tetramethylurea in formamide and water a comparative analysis of volume characteristics and solute solute interaction parameters at temperatures from 288 15 to 328 15 k and ambient pressure
Journal of Chemical & Engineering Data, 2019Co-Authors: Evgeniy V. Ivanov, Andrey V. Kustov, Elena Yu. LebedevaAbstract:Densities of urea (U) and Tetramethylurea (TMU) solutions in formamide (FA) and water with a solute molality of up to ∼2 mol kg–1 were measured at T = 288.15, 298.15, 308.15, 318.15, and 328.15 K a...
Andrey V. Kustov - One of the best experts on this subject based on the ideXlab platform.
-
solutions of urea and Tetramethylurea in formamide and water a comparative analysis of volume characteristics and solute solute interaction parameters at temperatures from 288 15 to 328 15 k and ambient pressure
Journal of Chemical & Engineering Data, 2019Co-Authors: Evgeniy V. Ivanov, Andrey V. Kustov, Elena Yu. LebedevaAbstract:Densities of urea (U) and Tetramethylurea (TMU) solutions in formamide (FA) and water with a solute molality of up to ∼2 mol kg–1 were measured at T = 288.15, 298.15, 308.15, 318.15, and 328.15 K a...
-
Solutions of Urea and Tetramethylurea in Formamide and Water: A Comparative Analysis of Volume Characteristics and Solute–Solute Interaction Parameters at Temperatures from 288.15 to 328.15 K and Ambient Pressure
Journal of Chemical & Engineering Data, 2019Co-Authors: Evgeniy V. Ivanov, Andrey V. Kustov, Elena Yu. LebedevaAbstract:Densities of urea (U) and Tetramethylurea (TMU) solutions in formamide (FA) and water with a solute molality of up to ∼2 mol kg–1 were measured at T = 288.15, 298.15, 308.15, 318.15, and 328.15 K a...
-
Standard Enthalpies and Heat Capacities of Solution of Urea and Tetramethylurea in Water
Journal of Chemical & Engineering Data, 2010Co-Authors: Andrey V. Kustov, Nataliya L. SmirnovaAbstract:This paper presents the results of accurate measurements of the enthalpies of solution of a typical hydrophilic solute, urea, and its hydrophobic derivative, Tetramethylurea, in water in the temperature range of (278.15 to 338.15) K. The standard enthalpies and heat capacities of solution are computed and compared with available literature values. Our results do indicate that the standard heat capacity of the solution of urea is very small, but it changes its sign at about the temperature minimum of the water heat capacity at constant pressure, while the heat capacity of Tetramethylurea solution in water is large, positive, and independent of the temperature.
G. Jancsó - One of the best experts on this subject based on the ideXlab platform.
-
Solute-solute correlation in aqueous solution of Tetramethylurea
Physica B-condensed Matter, 1997Co-Authors: S. Ansell, László Cser, T. Grósz, G. Jancsó, Pál Jóvári, Alan K. SoperAbstract:Abstract The HH radial distribution function obtained by of a wide-angle neutron scattering experiment on a 2 molar aqueous solution of Tetramethylurea at 10°C using the isotope substitution method is reported.
-
The nature of the interaction of Tetramethylurea in various solvents
Physica B-condensed Matter, 1997Co-Authors: László Cser, T. Grósz, G. Jancsó, G. KáliAbstract:Abstract The results of the quasi-elastic neutron scattering experiments carried out on dilute aqueous solutions of Tetramethylurea (TMU) are reported. The concentration dependence of the translational diffusion coefficients of TMU and water is interpreted in terms of solute-solute interactions derived from previous small-angle neutron scattering studies.
-
Neutron scattering on dense solutions of Tetramethylurea
Physica B-condensed Matter, 1995Co-Authors: S. Borbély, László Cser, T. Grósz, G. JancsóAbstract:Abstract The results of small-angle neutron scattering (SANS) carried out on aqueous and CS 2 solutions of Tetramethylurea (TMU) are compared. It is shown that the SANS data indicate the formation of TMU—TMU dimers in both solutions.
-
Free-energy simulation studies on the hydration of Tetramethylurea and tetramethylthiourea
Chemical Physics Letters, 1995Co-Authors: Mihaly Mezei, G. JancsóAbstract:Free-energy simulations are presented calculating the difference between the hydration free energies of Tetramethylurea and tetramethylthiourea. The results are combined with estimates of the free energies of evaporation (sublimation) to explain the difference in the solubilities of the two compounds. The free energy simulations used thermodynamic integration and were repeated with two parametrizations and with different polynomial paths.
-
Structure and dynamics of aqueous solutions of Tetramethylurea
Physica B: Condensed Matter, 1992Co-Authors: László Cser, T. Grósz, G. Jancsó, B. Farago, Yu.m. OstanevichAbstract:Three types of neutron scattering experiments on solutions of Tetramethylurea (TMU) in water are reported: The dependence of the small angle scattering pattern on the concentration and on the contrast variation controlled by the isotopic composition of the solvent (H2O to D2O ratio), the incoherent quasi-elastic scattering, and coherent quasi-elastic scattering measurements by using appropriate mixtures of Tetramethylurea and deuterated Tetramethylurea dissolved in two different mixtures of heavy and light water. The results show that there is an attractive interaction between the TMU molecules in the aqueous TMU solution, that there are TMU pairs in the relatively dilute solutions. All these data can be intrerpreted in the frame of the hypothesis that there is a pair formation of the TMU molecules connected by hydrogen bonds.
Léa Barbieri Zinner - One of the best experts on this subject based on the ideXlab platform.
-
Tetramethylurea adducts of the tricyclopentadienyl lanthanide complexes
Polyhedron, 1993Co-Authors: Ângela Domingos, Noémia Marques, A. Pires De Matos, Maria Das Graças Da Silva-valenzuela, Léa Barbieri ZinnerAbstract:Abstract The Tetramethylurea adducts of tricyclopentadienyl lanthanide(III) complexes, Cp3Ln·TMU (Ln = La, Ce, Nd, Sm, Eu and Yb, TMU = 1,1,3,3-Tetramethylurea), have been isolated by addition of the stoichiometric amount of (CH3)2NCON(CH3)2 to Cp3Ln·THF, in hexane. The compounds were characterized by standard techniques and the molecular structures of Cp3Ce·TMU and Cp3Nd·TMU were determined by single crystal X-ray diffraction analysis. The two compounds are isomorphous. The metal centre is tetrahedrally coordinated.