scholarly journals THERMODYNAMIC PROPERTIES OF ORGANIC ACIDS AND SOME THEIR DERIVATIVES

2019 ◽  
Vol 62 (11) ◽  
pp. 38-45
Author(s):  
Vitaly V. Ovchinnikov ◽  
Alexey A. Kulakov ◽  
Irina G. Grigor′eva ◽  
Svetlana A. Maltseva
Keyword(s):  
Experimental Data ◽  
Organic Acids ◽  
Gas Phase ◽  
Thermodynamic Functions ◽  
Bond Energies ◽  
Additional Material ◽  
Electron Pairs ◽  
Valence Electrons ◽  
Heats Of Combustion

The heats of vaporization, combustion, formation, entropy and the heat capacities in different phases of different carbonic acids and their derivatives: acetates, esters with fatty radicals, two-, three- and four-basic acids (52 compounds) were analysed in the framework of one-parametric mathematic equations. The experimental data of all chosen one-, two-, three- and four-basic acids were analyzed. It was determined, that all thermodynamic functions of these types of compounds depend on the number of valence electrons N, from which the sum of lone electron pairs g as represented in the equations Δvap,c,fH° = i ±  f (N-g) and S°(Cp) = i ±  f (N-g) is excluded. The coefficients f in the first equations is in the range of 104-113 kJ mol-1 electron-1, that corresponds to the same values f in the equations, which are mentioned in our earlier papers on the determination of the heats of combustion of organic acids. As concerned of coefficient i in the received equations, necessary to note that situation is not synonymous as with the coefficient f. The magnitudes of this coefficient are different in the equations of vaporization, combustion, formation also as in the equations of entropy and the heat of capacity. On the base of literary experimental data we calculated the 29 new equations, which can be used for the calculation of the same thermodynamic functions for other new organic acids and especially bioorganic substances with the useful properties. Necessary to add, that the received equations can serve as additional material for the calculation of the bond energies of fatty acids and their derivatives in gas phase.

The hydrogen bond energies of the bihalide ions XHX− and YHX−

1985 ◽  
Vol 63 (7) ◽  
pp. 1399-1406 ◽  
Author(s):  
G. Caldwell ◽  
P. Kebarle
Keyword(s):  
Hydrogen Bond ◽  
Gas Phase ◽  
Free Energies ◽  
Bond Energies ◽  
Solvation Energies ◽  
Complete Set ◽  
Lattice Energies ◽  
Gas Phase Ion ◽  
Hydrogen Bond Energies

Experimental measurements of the gas phase ion equilibria X− + HX = XHX−, X−(HX)n−1 + HX = X−(HX)n, and X− + HY = XHY where X, Y = Cl, Br, I, with a high pressure mass spectrometer, combined with the recent determination of F− + HF = FHF− by Larson and McMahon, provide a very complete set of hydrogen bond dissociation enthalpies and free energies for the hydrogen bihalide ions. The bond energy trends in the different XHX− and XHY− are discussed. The data can be used also for the evaluation of lattice energies of salts containing the bihalide ions and for determinations of the solvation energies of these ions.

Structures, binding energies, and thermodynamic functions of NH4+, NH3•+, and their H2O complexes

1993 ◽  
Vol 71 (9) ◽  
pp. 1368-1377 ◽  
Author(s):  
David A. Armstrong ◽  
Arvi Rauk ◽  
Dake Yu
Keyword(s):  
Experimental Data ◽  
Gas Phase ◽  
Thermodynamic Functions ◽  
Hydration Shell ◽  
Binding Energies ◽  
Basis Set ◽  
Free Energies ◽  
Hydrated Complexes ◽  
Optimized Geometries ◽  
First Hydration Shell

Ab initio calculations are performed for [Formula: see text] and [Formula: see text] complexes for n = 0–5. For n = 0 and 1, the geometries of the complexes are optimized at the HF/6-31 + G* and MP2/6-31 + G* levels, and the energies are evaluated at the G2 level. For n = 2–5, the geometry optimizations and frequency calculations are carried out at the HF/6-31 + G* level, and the MP2/6-31 + G* energies are calculated at the HF optimized geometries. Basis set superposition errors are corrected by the Boys–Bernardi scheme at the HF/6-31 + G* level. The gas phase thermodynamic properties [Formula: see text] are evaluated as functions of temperature using standard statistical methods. Based on the calculated binding energies and the thermodynamic functions, the incremental changes in enthalpies and free energies, ΔHn and ΔGn, for the gas phase equilibria (H2O)n−1 M+ + H2O → (H2O)nM+ for M+ = NH4+ and NH3•+, are evaluated in comparison with the experimental data for [Formula: see text] the present results suggest conformations for the hydrated complexes observed in the experiments. The total free energy change for filling the first hydration shell is significantly more negative for NH3•+ than for NH4+.

Determination of Natural Loss of Gasoline and Diesel Fuel during the Tank Storage

2021 ◽  
Vol 627 (5) ◽  
pp. 28-31
Author(s):  
D .S. Kopitsyn ◽  
◽  
P. A. Gushchin ◽  
A. A. Panchenko ◽  
F. V. Timofeev ◽  
...  
Keyword(s):  
Experimental Data ◽  
Temperature Dependence ◽  
Gas Phase ◽  
Diesel Fuel ◽  
Empirical Equation ◽  
Petroleum Products ◽  
Antoine Equation ◽  
Tank Storage

In this work, we studied the processes of evaporation of gasoline and diesel fuel during their storage. We assessed of the temperature dependence of the content of hydrocarbon vapors in the gas phase over petroleum products. It was found that the experimental data are best described by the empirical equation based on the Antoine equation. An algorithm is proposed for calculating the natural loss of gasoline and diesel fuel, as well as approaches to its reduction.

The Hydrogen Bond Energies in ClHCl− and Cl−(HCl)n

1974 ◽  
Vol 52 (13) ◽  
pp. 2449-2453 ◽  
Author(s):  
R. Yamdagni ◽  
P. Kebarle
Keyword(s):  
Gas Phase ◽  
Equilibrium Constants ◽  
Bond Energies ◽  
Gas Phase Reactions ◽  
Weakly Bound ◽  
Pulsed Electron Beam ◽  
Large N ◽  
Different Temperatures ◽  
Hydrogen Bond Energies

The equilibrium constants for the gas phase reactions: Cl−(HCl)n = Cl−(HCl)n−1 + HCl, (n, n−1) were measured at different temperatures with a pulsed electron beam high pressure mass spectrometer. This allowed determination of ΔGn,n−10, ΔHn,n−10, and ΔSn,n−10 for reactions with n = 1 to n = 4. The enthalpy change for the reaction: (ClHCl)− = Cl− + HCl was ΔH1.00 = 23.7 kcal/mol. This value is much higher than the literature value of 14.2 kcal/mol based on Born cycles. The stabilities of the Cl−(HCl)n clusters are compared with those of OH−(H2O)n and Cl−(H2O)n measured earlier. It is found that the (ClHCl)− is nearly as stable as the (HOHOH)− species but that the stabilities of the higher Cl−(HCl)n clusters decreases much more rapidly than that of OH−(H2O)n. The initial strong interaction in (ClHCl) is assumed to be due to the high polarizability of Cl. For large n this effect becomes unimportant. Cl−HOH is much more weakly bound than (ClHCl)−, however, at high n the Cl−(H2O)n interactions become more favorable.

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