Temperature dependence of heats of vaporization, saturated vapour pressures and cohesive energies for a group of amines

1979 ◽  
Vol 44 (12) ◽  
pp. 3521-3528 ◽  
Author(s):  
Vladimír Majer ◽  
Václav Svoboda ◽  
Josef Koubek ◽  
Jiří Pick
Keyword(s):  
Temperature Dependence ◽  
Saturated Vapour ◽  
Temperature Dependences ◽  
Experimental Values ◽  
Cohesive Energies ◽  
Heats Of Vaporization

The temperature dependences of heats of vaporization of propylamine, isopropylamine, butylamine, isobutylamine, sec-butylamine, cyclohexylamine, diethylamine and triethylamine and saturated vapour pressures of butylamine, isobutylamine, sec-butylamine and triethylamine were measured. The cohesive energies of amines studied in dependence on temperature were calculated from the experimental values.

Temperature dependence of heats of vaporization, saturated vapour pressures and cohesive energies of secondary amines

1979 ◽  
Vol 44 (12) ◽  
pp. 3533-3540 ◽  
Author(s):  
Libor Pětroš ◽  
Vladimír Majer ◽  
Josef Koubek ◽  
Václav Svoboda ◽  
Jiří Pick
Keyword(s):  
Experimental Data ◽  
Liquid Phase ◽  
Temperature Dependence ◽  
Secondary Amines ◽  
Saturated Vapour ◽  
Cohesive Energies ◽  
Heats Of Vaporization

The temperature dependence of heats of vaporization of methylisopropylamine, ethylisopropylamine, propylisopropylamine, diisopropylamine, butylisopropylamine, ethylbutylamine and dibutylamine has been measured. Further, the dependence of saturated vapour pressures on temperature has been measured for methylisopropylamine, ethylisopropylamine, propylisopropylamine, butylisopropylamine, diisopropylamine and ethylbutylamine. The densities of the liquid phase at 25°C have been determined for methylisopropylamine, ethylisopropylamine, propylisopropylamine, butylisopropylamine and ethylbutylamine. The cohesive energies at several temperatures have been computed from the experimental data for all the substances of the set.

Determination of heats of vaporization and some other thermodynamic quantities for several fluorinated halogen derivatives of ethane and propane

1980 ◽  
Vol 45 (11) ◽  
pp. 3063-3068 ◽  
Author(s):  
Vladimír Majer ◽  
Václav Svoboda ◽  
Antonín Pošta ◽  
Jiří Pick
Keyword(s):  
Chemical Properties ◽  
Thermodynamic Quantities ◽  
Saturated Vapour ◽  
Physico Chemical ◽  
Temperature Dependences ◽  
Two Temperatures ◽  
Cohesive Energies ◽  
Derivatives Of ◽  
Heats Of Vaporization

Some physico-chemical properties were determined for 1,1,1-trichlorotrifluoroethane, 1,1,2-trichlorotrifluoroethane, 1-bromo-1-chloro-2,2,2-trifluoroethane and 1,2-dichlorohexafluoropropane. For all the substances, their heats of vaporization in dependence on temperature were measured and their densities and refractive indices at two temperatures were determined. For 1,1,1-trichlorotrifluoroethane and 1,2-dichlorohexafluoropropane the saturated vapour pressures were measured, too. The temperature dependences of standard heats of vaporization, vaporization internal energies and cohesive energies were determined on the basis of the experimental data.

scholarly journals SYNTHESIS AND STUDY OF THERMODYNAMIC PROPERTIES OF NEW ZINCATE-MANGANITES NdM2IIZnMnO6 (MII − Mg, Ca)

2018 ◽  
Vol 61 (3) ◽  
pp. 16
Author(s):  
Bulat К. Kasenov ◽  
Shuga B. Kasenova ◽  
Zhenisgul I. Sagintaeva ◽  
Yerbolat Y. Kuanyshbekov ◽  
Meruert O. Turtubaeva
Keyword(s):  
Heat Capacity ◽  
Phase Transitions ◽  
Thermodynamic Properties ◽  
Temperature Dependence ◽  
Ceramic Technology ◽  
Cell Parameters ◽  
Dynamic Calorimetry ◽  
Temperature Dependences ◽  
Calorimetric Studies ◽  
Experimental Values

Zincate-manganites with the composition NdM2IIZnMnO6 (MII− Mg, Ca) were synthesized using ceramic technology from oxides of Nd (III), Zn (II), Mn (III) and carbonates of alkaline-earth metals - magnesium and calcium. X-ray patterns of the prepared substancies were measured on a DRON-2.0 diffractometer. We established that they crystallize in the cubic system with the following unit cell parameters: NdMg2ZnMnO6 – а=13.927±0.035 Å, Z = 4, V0 = 2701.36±0.11 Å3, V0el.cell. = 675.34±0.03 Å3, ρX-ray = 4.20, ρpycn. = 4.19±0.01 g/cm3; NdCa2ZnMnO6 – а=13.910±0.030 Å, Z = 4, V0 = 2691.45±0.10 Å3, V0el.cell. = 672.86±0.03 Å3, ρX-ray = 4.04, ρpycn. = 4.01±0.08 g/сm3. The temperature dependence of the heat capacity of NdMg2ZnMnO6 and NdCa2ZnMnO6 was studied by dynamic calorimetry in the range of 298.15-673 K on the IT-S-400 calorimeter. Five parallel experiments were performed at each temperature point with 25 K step. The results were averaged and analyzed using mathematical statistics. As a result of calorimetric studies of the heat capacity, within the temperature range of 298.15-673 K, we discovered on the curves of the temperature dependence of heat capacity the phase transitions of the II kind at the following temperatures: 373, 548 К- NdMg2ZnMnO6, 448, 573 К – NdCa2ZnMnO6. These phase transitions were probably due to Schottky effects -the transition from semiconductivity to metallic conductivity, and variations in capacity, dielectric permittivity, the occurrence of Curie or Neel points. The equations of the temperature dependence of the heat capacity were derived on the basis of the experimental values with account the temperatures of the phase transitions. By the ion increment method, we calculated the standard entropies of the compounds investigated. We calculated the temperature dependences of С°р(Т) and thermodynamic functions Н°(Т)-Н°(298.15), S°(T) and Фхх(Т).Forcitation:Kasenov B.K., Kasenova Sh.B., Sagintaeva Zh.I., Kuanyshbekov Е.Е., Turtubaeva М.О. Synthesis and study of thermodynamic properties of new zincate-manganites NdM2IIZnMnO6 (MII − Mg, Ca). Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2018. V. 61. N 3. P. 16-20

Determination of heats of vaporization and some other thermodynamic quantities for three fluorinated halogen ethanes

1981 ◽  
Vol 46 (4) ◽  
pp. 817-822 ◽  
Author(s):  
Vladimír Majer ◽  
Václav Svoboda ◽  
Antonín Pošta ◽  
Jiří Pick
Keyword(s):  
Thermodynamic Properties ◽  
Temperature Dependence ◽  
Refractive Indices ◽  
Thermodynamic Quantities ◽  
Saturated Vapour ◽  
Two Temperatures ◽  
Heats Of Vaporization

Some thermodynamic properties were investigated for three fluorinated halogen ethanes: 1-bromo-2-chloro-1,1,2-trifluoroethane, 1,2-dibromotetrafluroethane and 1,2-dibromo-1-chlorotrifluoroethane. The temperature dependence of heats of vaporization, saturated vapour pressures, densities and refractive indices was measured at two temperatures. On the basis of the experimental quantities obtained, the standard heats of vaporization and the cohesive and internal energies of vaporization in their dependence on temperature were determined.

Determination of heats of vaporization and some other thermodynamic properties for four substituted hydrocarbons

1982 ◽  
Vol 47 (2) ◽  
pp. 543-549 ◽  
Author(s):  
Václav Svoboda ◽  
Vladimíra Charvátová ◽  
Vladimír Majer ◽  
Vladimír Hynek
Keyword(s):  
Thermodynamic Properties ◽  
Temperature Dependence ◽  
Constant Pressure ◽  
Pressure Curve ◽  
Saturated Vapour Pressure ◽  
Vapour Pressure Curve ◽  
The Difference ◽  
Cohesive Energies ◽  
Heats Of Vaporization

The temperature dependence of heats of vaporization and some other derived thermodynamic properties were determined for four substituted hydrocarbons, viz. 2,2,4-trimethylpentane,1-octene, ethylbenzene and n-butylbenzene. The temperature dependence of heats of vaporization was measured and, on the basis of these data, the values of standard heats of vaporization, internal and cohesive energies, entropies of vaporization and the difference of heat capacities of liquid and vapour at constant pressure and along the saturated vapour pressure curve were computed.

Determination of heats of vaporization and some other thermodynamic quantities for four alkylcycloparaffins

1981 ◽  
Vol 46 (12) ◽  
pp. 2983-2988 ◽  
Author(s):  
Václav Svoboda ◽  
Vladimíra Charvátová ◽  
Vladimír Majer ◽  
Jiří Pick
Keyword(s):  
Temperature Dependence ◽  
Constant Pressure ◽  
Heat Capacities ◽  
Saturation Line ◽  
Thermodynamic Quantities ◽  
Cohesive Energies ◽  
Heats Of Vaporization

Heats of vaporization and some other related thermodynamic quantities were determined for the four alkylcycloparaffins: ethylcyclopentane, n-butylcyclopentane, ethylcyclohexane and tert-butylcyclohexane. The temperature dependence of heats of vaporization was measured and employed for calculating standard heats of vaporization, internal and cohesive energies of vaporization, entropies of vaporization, and differences between heat capacities of liquids and vapours at constant pressure and along the saturation line of vapours.

Temperature Dependences in the O + OH → O2 + H Reaction. Quasiclassical Trajectory Calculation

1993 ◽  
Vol 58 (2) ◽  
pp. 234-243 ◽  
Author(s):  
Viliam Klimo ◽  
Martina Bittererová ◽  
Stanislav Biskupič ◽  
Ján Urban ◽  
Miroslav Micov
Keyword(s):  
Temperature Dependence ◽  
Energy Surface ◽  
Analytical Form ◽  
Mean Values ◽  
Quantum Numbers ◽  
Mean Lifetime ◽  
Temperature Dependences ◽  
Quasiclassical Trajectory Calculation ◽  
The Mean ◽  
Combustion Processes

The reaction O + OH → O2 + H in conditions of combustion of hydrocarbons and polymers was modelled by using the method of quasiclassical trajectories. The potential energy surface was determined by the multiconfiguration interaction method and fitted with the analytical form of the extended LEPS function. Attention was paid to the mean values of the vibrational and rotational quantum numbers of O2 molecules and their temperature dependence. The temperature dependence of the mean lifetime of the OOH collision complex was also examined. The calculated rate constants were analyzed and compared with the experimental data over the temperature region of the combustion processes.

The Bender Equation of State and Virial Coefficients

2000 ◽  
Vol 65 (9) ◽  
pp. 1464-1470 ◽  
Author(s):  
Anatol Malijevský ◽  
Tomáš Hujo
Keyword(s):  
Equation Of State ◽  
Virial Coefficient ◽  
Virial Coefficients ◽  
Low Density ◽  
Second Virial Coefficients ◽  
The Third ◽  
Temperature Dependences ◽  
Experimental Values

The second and third virial coefficients calculated from the Bender equation of state (BEOS) are tested against experimental virial coefficient data. It is shown that the temperature dependences of the second and third virial coefficients as predicted by the BEOS are sufficiently accurate. We conclude that experimental second virial coefficients should be used to determine independently five of twenty constants of the Bender equation. This would improve the performance of the equation in a region of low-density gas, and also suppress correlations among the BEOS constants, which is even more important. The third virial coefficients cannot be used for the same purpose because of large uncertainties in their experimental values.

The Urbach Rule for the Sodium- and Potassium-Halides

1974 ◽  
Vol 29 (1) ◽  
pp. 145-157 ◽  
Author(s):  
Tetsuhiko Tomiki ◽  
Takeo Miyata ◽  
Hirokazu Tsukamoto
Keyword(s):  
Temperature Dependence ◽  
Acoustic Phonon ◽  
Frequency Factor ◽  
Host Lattice ◽  
Exciton Peak ◽  
Urbach Rule ◽  
Temperature Dependences ◽  
Hole Band ◽  
Sodium And Potassium ◽  
Potassium Halides

Phenomenological and physical aspects of the intrinsic tail spectra of the alkalihalides are studied referring to the new results on the intrinsic tail spectra of KBr and KI and to the temperature dependences of the lowest-energy Γ-exciton peak of the sodium- and potassium-halides. Systematically analysing the temperature dependence of the steepness parameter σs (T) of the Urbach rule for these halides, it is found that the frequency factor has the value nearly equal to the acoustic phonon energy at X or L of each host lattice and the steepness constant σs0 becomes larger in passing from fluoride to iodide. This halogen dependence of σs0 is discussed in terms of the hole band-mass of the Γ8-level.

scholarly journals The role of enzyme dynamics and tunnelling in catalysing hydride transfer: studies of distal mutants of dihydrofolate reductase

2006 ◽  
Vol 361 (1472) ◽  
pp. 1307-1315 ◽  
Author(s):  
Lin Wang ◽  
Nina M Goodey ◽  
Stephen J Benkovic ◽  
Amnon Kohen
Keyword(s):  
Temperature Dependence ◽  
Dihydrofolate Reductase ◽  
Isotope Effects ◽  
Hydride Transfer ◽  
Activation Parameters ◽  
Physical Nature ◽  
Enzyme Dynamics ◽  
Temperature Dependences ◽  
Donor Acceptor ◽  
Significant Temperature

Residues M42 and G121 of Escherichia coli dihydrofolate reductase ( ec DHFR) are on opposite sides of the catalytic centre (15 and 19 Å away from it, respectively). Theoretical studies have suggested that these distal residues might be part of a dynamics network coupled to the reaction catalysed at the active site. The ec DHFR mutant G121V has been extensively studied and appeared to have a significant effect on rate, but only a mild effect on the nature of H-transfer. The present work examines the effect of M42W on the physical nature of the catalysed hydride transfer step. Intrinsic kinetic isotope effects (KIEs), their temperature dependence and activation parameters were studied. The findings presented here are in accordance with the environmentally coupled hydrogen tunnelling. In contrast to the wild-type (WT), fluctuations of the donor–acceptor distance were required, leading to a significant temperature dependence of KIEs and deflated intercepts. A comparison of M42W and G121V to the WT enzyme revealed that the reduced rates, the inflated primary KIEs and their temperature dependences resulted from an imperfect potential surface pre-arrangement relative to the WT enzyme. Apparently, the coupling of the enzyme's dynamics to the reaction coordinate was altered by the mutation, supporting the models in which dynamics of the whole protein is coupled to its catalysed chemistry.

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