Authors:X. Zielenkiewicz, G. Perlovich, and M. Wszelaka-Rylik
A new device, based on the inert gas flow method, for measuring the vapour pressure and the determination of the enthalpy of sublimation in a wide range of temperatures (up to 573 K) is described in this paper. The limits of the flow rate as important experimental parameter were determined for the given instrument. The results of calibration showed a good precision and reproducibility of the measurements of the enthalpy of sublimation. The results of the determination of some derivatives of pyrimidine were presented.
Authors:P. Storoniak, K. Krzymiński, and J. Błażejowski
Enthalpies of sublimation of acridine, 9-acridinamine, N-methyl-9-acridinamine, 10-methyl-9-acridinimine, N,N-dimethyl-9-acridinamine
and N-methyl-10-methyl-9-acridinimine were determined by fitting to thermogravimetric curves with the Clausius-Clapeyron relationship.
These values compare well with crystal lattice energies predicted theoretically as the sum of electrostatic, dispersive and
repulsive interactions. Partial charges for these calculations were obtained on an ab initio level, while atomic parameters
were taken from literature.
Enthalpies and entropies of sublimation for N-acetylglycine amide (NAGA), N-acetyl-L-alanine amide (L-NAAA), and N-acetyl-D-leucine amide (D-NALA) were determined from the dependence of their vapour pressures on temperature, as measured by the torsion-effusion method.
Authors:Yu. Maksimuk, V. Sokolov, V. Sevruk, and P. Trahanov
The enthalpies of combustion for 4-formylbenzoic acid (I), 4-methylbenzyl alcohol (II), and trimethyl 1,2,4-benzenetricarboxylate
(III) were determined by the bomb calorimetry method. Enthalpies of sublimation for I and II were measured with a calorimeter.
The contributions of different substituents to the standard enthalpies of formation for benzene derivatives in the gas state
Enthalpy of solution, ΔHsolo
, enthalpy of sublimation, ΔHsublo
, apparent partial molar volume and heat capacities,V2o
were determined for aqueous solutions of thirty alkylated derivatives of uracyl and adenine, eight derivatives of cytosine
and guanine. Calculated accessible surface areas and molar volumes are presented, too. The values of enthalpy of solution,
enthalpy of sublimation can be useful in the studies on the nature of interaction between these compounds and water molecules.
Apparent partial molar volume and heat capacity give a new aspect on hydrophob properties of the examined nucleic acid base
The standard (p0=0.1 MPa) molar enthalpy of formation of 1-cyanoacetylpiperidine, in the crystalline state, at T=298.15 K, has been derived from measurements of its standard massic energy of combustion, by static bomb combustion calorimetry,
as ΔfHm0=−217.1±1.4 kJ mol−1. The standard molar enthalpy of sublimation was measured, at T=298.15 K, by the microcalorimetric sublimation technique as ΔcrgHm0=103.5±1.9 kJ mol−1.
The standard (po=0.1 MPa) molar energies of combustion for the crystalline 1-benzyl-4-piperidinol and 4-piperidine-piperidine, and for the
liquid 4-benzylpiperidine, were measured by static bomb calorimetry, in oxygen, at T=298.15 K. The standard molar enthalpies of sublimation or vaporization, at T=298.15 K, of these three compounds were determined by Calvet microcalorimetry.
Those values were used to derive the standard molar enthalpies of formation, at T=298.15 K, in their condensed and gaseous phase, respectively.
Authors:Luis H. Blanco, Yina P. Salamanca, and Edgar F. Vargas
between the enthalpy of solution at infinite dilution, , and the enthalpyofsublimation, , according to the equation:
where α is the thermal expansion of the solvent. The last term in Eq. 1 accounts for the correction of the experimental
Correlations between the enthalpyofsublimation and the temperature of sublimation at a reference pressure, or between the enthalpyofsublimation and the standard Gibbs energy of sublimation at 298.15 K have been