Thermochemical investigations on arylethynes: I. Heats of combustion of some diarylethynes

Coops, J.; Hoijtink, G. J.; Kramer, Th. J. E.; Faber, A. C.

doi:10.1002/recl.19530720909

Cited by 6 publications

(2 citation statements)

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“…Table lists thermodynamic functions of DPhA formation in the crystal and ideal gas states at T = 298.15 K. The standard Gibbs free energy of formation, Δ f G m 0 , was calculated from the formula: normalΔ normalf G normalm 0 = normalΔ normalf H normalm 0 − T · normalΔ normalf S normalm 0 using the experimental value of absolute entropy obtained by the third law of thermodynamics (Table ). The ideal gas enthalpy of formation Δ f H m 0 (g) = (407.5 ± 1.6) kJ·mol –1 was obtained on the basis of the enthalpy of formation in a solid state, Δ f H m 0 (cr), and enthalpy of sublimation of DPhA . The function Δ f S m 0 in eq is the difference between the values of absolute entropies of the final and initial products in the reaction: 14 normalC false( cr false) + 5 normalH 2 false( normalg false) = normalC 14 normalH 10 false( cr false) …”

Section: Thermodynamic Calculation and Discussionmentioning

confidence: 99%

“…The experimental heat combustion of crystal DPhA and derived enthalpy of formation Δ f H m 0 (cr) = (312.40 ± 1.1) kJ·mol –1 at T = 298.15 K were determined by Coops et al The data on the ideal gas enthalpy of formation obtained by experimental and calculation methods disagree from (385 to 427.96) kJ·mol –1 . ,− The enthalpy of formation Δ f H m 0 (g)(exp) = (407.5 ± 1.6) kJ·mol –1 was appreciated in ref as a reliable quantity calculated from Δ f H m 0 (cr) and Δ sub H m 0 values at T = 298.15 K. Using the AM1 semiempirical method, Palafox computed the enthalpy of formation Δ f H m 0 (g)(calc) = 409.5 kJ·mol –1 , which agreed with the experimental value in the best way. In ref the ideal gas absolute entropy was calculated by the same method, S m 0 (g)(298K) = 452.0 J·K –1 ·mol –1 .…”

Section: Introductionmentioning

confidence: 99%

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Heat Capacity and Thermodynamic Functions of Diphenylacetylene

et al. 2011

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The heat capacity of diphenylacetylene was measured by vacuum adiabatic calorimetry over the temperature range from (8 to 371) K. The temperature and the enthalpy and entropy of fusion have been determined. The standard thermodynamic functions (changes of the entropy, enthalpy, and Gibbs free energy) were obtained for the crystal and liquid states in the temperature interval studied and for the ideal gas state at T = 298.15 K. The ideal gas entropies in wide temperature range were also calculated by the principle of additivity and statistical thermodynamics using molecular constants determined by the density functional theory (DFT) method on the level B3LYP/cc-pVTZ. The S m 0(g)(298.15K) values derived from the experimental and calculated data agree within (0.3 to 0.2) % which confirms their reliability. The data on thermodynamic properties of diphenylacetylene studied earlier and in this work were critically analyzed for verification of their reliability and mutual consistency.

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Section: Thermodynamic Calculation and Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Heat Capacity and Thermodynamic Functions of Diphenylacetylene

et al. 2011

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Zur Konjugation in makrocyclischen Bindungssystemen, XV. Benzo[12]annulene: 5.6.11.12.17.18‐Hexadehydro‐tribenzo[a.e.i]cyclododecen

Staab

Graf

1970

Chem. Ber.

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Conjugation inFormal wurde der Ubergang 1 --e 3 der cyclisierenden Trimerisierung von Acetylenen zu aromatischen Verbindungen --z. B. Diphenylacetylen -> Hexaphenylbcnzol-5) ~ entsprechen, die durch ijbergangsmctall-Verhiudungen katalysiert wird. Trotz der durch die Arbeiten yon Reppr und Mitarbb.6) angeregten intensiven Bearbeitung dieses Gebietes konnte der Mechanismus der Acetylen-Cyclisierung, vor allem wegen der Instabilitiit der KomplexZwischenstufen, bis heutc nicht eindeutig auFgeklairt werden 7 )~ Als eine von mehreren Moglichkeiten wurde angenommcn, daR eine synchrone Cyclisierung der drei Acetylen-Molekcln aus eincr Zwischenstufe erfolgt, in der die drei Dreifachbindungen unter dem koordinierenden Einflul3 des Metalls angenahert in eincr Ebene angeordnet sind 8).Da in 1 eine solche Aoordnung der Dreifachbindungen vorliegt, andererseits aber eine Cyclisierung wegen der Ringspannung des Reaktionsproduktes 3 kaum moglich sein s o h , war hier eine Isolierung voii ~bergangsmetall-Komplexen denkbar, deren Strukturaufkliirung fur den Mechanismus der cyclisierenden Trimerisierung von Acetylenen aufschluRreich scin konnte.U ber eine zu 1 analogc Verbindung, bei der jedoch zwischen die aromatischcn Ringe nicht jeweils eine, sondern zwei Dreifachbindungen eingeschoben sein sollten, war vor einigen Jahren berich tet worden9'. Die urspriinglich angenommcne Struktur hat sich jedoch spater als unrichtig erwiesen: die oxydative Kupplung des o-Diathinylbenzols fiihrte iiberraschender- Chern. Rer. 90, 543 (1957). 1110Statrb und Grnf Jahrg. 103

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