The Temperature Dependence of the Enthalpy of Formation of the Amide Hydrogen Bond; the Urea Model1

1965 ◽  
Vol 69 (5) ◽  
pp. 1704-1706 ◽  
Author(s):  
Gordon C. Kresheck ◽  
Harold A. Scheraga
Keyword(s):  
Hydrogen Bond ◽  
Temperature Dependence ◽  
Enthalpy Of Formation ◽  
Amide Hydrogen ◽  
The Enthalpy Of Formation

Chaleurs de mélange du système éthyl-3 pentanol-3 tétrachlorure de carbone

1972 ◽  
Vol 50 (19) ◽  
pp. 3207-3211
Author(s):  
H. Brusset ◽  
M. Desgranges ◽  
J. C. Lecoq
Keyword(s):  
Hydrogen Bond ◽  
Carbon Tetrachloride ◽  
Enthalpy Of Formation ◽  
Infinite Dilution ◽  
Excess Enthalpy ◽  
Molar Fraction ◽  
Enthalpies Of Mixing ◽  
Associated Solutions ◽  
Classic Theory ◽  
The Enthalpy Of Formation

The enthalpies of mixing in the system 3-ethyl-3 pentanol–carbon tetrachloride were measured by microcalorimetry. The classic theory of associated solutions leads to an expression for the excess enthalpy which we have simplified by introducing the heat at infinite dilution for the alcohol. The resulting expression allows the enthalpy of formation of a hydrogen bond to be calculated using calorimetric and tonometric results. The calculations show that this enthalpy is independent of the concentration of the solution (up to 0.45 in molar fraction) and is in agreement with the literature.

Thermochemistry of Organic and Heteroorganic Species. Part IX. Photoionization Studies of Isomerization and Fragmentation of Polysubstituted Cyclopropenes: Phenyl-Substituted Cyclopropenes

2000 ◽  
Vol 6 (1) ◽  
pp. 53-64 ◽  
Author(s):  
V.V. Takhistov ◽  
I.N. Domnin ◽  
D.A. Ponomarev
Keyword(s):  
Mass Spectrometry ◽  
Enthalpy Of Formation ◽  
Good Alternative ◽  
Enthalpies Of Formation ◽  
Isodesmic Reactions ◽  
Ion Structure ◽  
Photoionization Mass Spectrometry ◽  
General Methodology ◽  
Fragment Ions ◽  
The Enthalpy Of Formation

Ionization and appearance energies of some fragment ions from 1,2,3-trimethy1-3-phenyl-, 3-methyl-1,2,3-triphenyl-, 1,2-diphenyl-3-methoxycarbonyl-, 1,2,3-triphenyl-3-methoxycarbonyl- and 1,3,3-triphenyl-2-methoxycarbonyl-cyclopropenes were measured by photoionization mass spectrometry. It was shown that in none of these compounds did the fragment ions possess the expected stable substituted cyclopropenium ion structure. Accordingly, possible schemes of molecular ion isomerization are given. The enthalpies of formation of nearly 50 substituted cyclopropenium ions, and ions of related structure, were estimated using series of isodesmic reactions. This publication, together with the previous works of the authors in this Journal, demonstrates the general methodology for estimation of the enthalpy of formation for even-electron ions. It is suggested that the present methodology can provide a good alternative to other estimation or computation procedures applied to the thermochemistry of ions.

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