Standard molar enthalpies of formation of 2-, 3- and 4-cyanobenzoic acids

Silva, Manuel A.V. Ribeiro da; Amaral, Luı́sa M.P.F.; Boaventura, Cristina R.P.; Gomes, José R. B.

doi:10.1016/j.jct.2008.04.004

Cited by 7 publications

(2 citation statements)

References 38 publications

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“…Our research group has been investigating the volatility of differently substituted benzoic acids − through vapor pressure measurements at different temperatures. For some of these compounds enthalpies of combustion were also measured, ,, enabling the determination of the enthalpy of formation in the crystalline and gaseous phases. This work continues the studies of volatility and enthalpies of formation of substituted benzoic acids.…”

Section: Introductionmentioning

confidence: 99%

Vapor Pressures and Enthalpies of Combustion of the Dihydroxybenzoic Acid Isomers

2009

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The Knudsen mass-loss effusion technique was used to measure the vapor pressures at different temperatures of the following dihydroxybenzoic acids : 2,3-dihydroxybenzoic acid, between (345.22 and 363.18) K; 2,4dihydroxybenzoic acid, between (376.22 and 392.11) K; 2,5-dihydroxybenzoic acid, between (372.14 and 388.92) K; 2,6-dihydroxybenzoic acid, between (347.14 and 365.17) K; 3,4-dihydroxybenzoic acid, between (387.12 and 403.26) K; and 3,5-dihydroxybenzoic acid, between (345.22 and 363.18) K. From the temperature dependences of the vapor pressure of the crystalline compounds, the standard (p 0 ) 10 5 Pa) molar enthalpies and Gibbs energies of sublimation, at T ) 298.15 K, were derived. For each of the six isomers the standard (p 0 ) 0.1 MPa) molar enthalpy of formation in the crystalline phase was derived from the experimental standard molar energy of combustion, in oxygen, measured by static-bomb combustion calorimetry at T ) 298.15 K. The combination of the standard molar enthalpy of formation in the crystalline phase with the standard enthalpy of sublimation yields the standard molar enthalpy of formation in the gaseous phase of the studied compounds.

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Section: Introductionmentioning

confidence: 99%

Vapor Pressures and Enthalpies of Combustion of the Dihydroxybenzoic Acid Isomers

2009

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“…In a previous work, concerning the thermochemistry of 2-, 3-and 4-cyanobenzoic acids [32] it was found that this composite method was capable of reproducing gas-phase standard molar enthalpies of this class of compounds. Therefore, this approach was used again in the present work.…”

Section: Computational Detailsmentioning

confidence: 99%