Gas-phase enthalpies of formation of ethyl hydroxybenzoates: An experimental and theoretical approach

Ledo, J. Manuel; Flores, Henoc; Hernández-Pérez, Julio M.; Ramos, Fernando M.; Camarillo, E. Adriana; Solano-Altamirano, J. Manuel

doi:10.1016/j.jct.2017.09.007

Cited by 12 publications

(13 citation statements)

References 48 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The equipment as well as more details on the procedure have been described elsewhere. 19,20 However, the equipment was recently calibrated and tested, 4 and the most relevant aspects are described below.…”

Section: ■ Experimental Methodsmentioning

confidence: 99%

“…21 The energy equivalent of the calorimeter was measured as ε(calor) = (10123.0 ± 0.7) J•K −1 , where the uncertainty is the standard deviation of the mean, calculated from seven experiments. 4 M4MB's samples were burned as pellets, whereas M2MB's samples, which are liquid at room temperature, were burned inside polyethylene bags. These bags have a combustion energy of −(46.3726 ± 0.0022) kJ•g −1 , 22 and the cotton yarn used (empirical formula: CH 1.742 O 0.921 19 ) has a combustion energy of −(16.9541 ± 0.0031) kJ•g −1 , which was determined in this work and is given in Table S1 of the Supporting Information.…”

Section: ■ Experimental Methodsmentioning

confidence: 99%

“…The combustion energies of the MMBs were determined with a static-bomb isoperibolic calorimeter. The equipment as well as more details on the procedure have been described elsewhere. , However, the equipment was recently calibrated and tested, and the most relevant aspects are described below.…”

Section: Experimental Methodsmentioning

confidence: 99%

“…1−3 Therefore, the accurate thermochemical characterization of these compounds turns out to be of great importance, and consequently their thermochemical properties have been widely studied and described in several papers. For instance, our research group has recently carried out a thermochemical study of ethyl and methyl hydroxybenzoates, 4,5 wherein the energetic effects stemming from exchanging the position of the hydroxy group within the aromatic ring, as well as the energetic effects caused by increasing the length of the ester chain, have been discussed. Furthermore, Almeida et al have studied structural properties and reported thermochemical properties of these types of substances.…”

Section: ■ Introductionmentioning

confidence: 99%

“…In addition, they are commonly used as preservatives in the food and cosmetic industry due to their inert and inexpensive qualities. − Therefore, the accurate thermochemical characterization of these compounds turns out to be of great importance, and consequently their thermochemical properties have been widely studied and described in several papers. For instance, our research group has recently carried out a thermochemical study of ethyl and methyl hydroxybenzoates, , wherein the energetic effects stemming from exchanging the position of the hydroxy group within the aromatic ring, as well as the energetic effects caused by increasing the length of the ester chain, have been discussed. Furthermore, Almeida et al have studied structural properties and reported thermochemical properties of these types of substances. − Especially, and closely related to our interests, Almeida et al have studied thermochemical properties of methyl 4-methoxybenzoate, which can be found as a volatile component in several plants and fungi. − …”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Thermochemical Study of Methyl n-Methoxybenzoates: An Experimental and Computational Approach

et al. 2019

Self Cite

View full text Add to dashboard Cite

In this work, we determine, both experimentally and computationally, structural and thermochemical properties of the methyl 2- and 4-methoxybenzoates. Combustion and vaporization enthalpies of these compounds were obtained experimentally through combustion calorimetry and thermogravimetry. From these properties, their standard molar enthalpies of formation in the gas phase, at T = 298.15 K, were also determined. In addition, we computed gas-phase enthalpies of formation of methyl 2-, 3-, and 4-methoxybenzoates using the composite method Gaussian G4, atomization reactions, and a weighted Boltzmann average. This average was performed over the stable conformers of each compound, and the respective Gibbs energies were used to compute the weights for the Boltzmann average. The analyses of the electronic density of the molecules and of noncovalent interactions were performed as well. We found a good agreement between our experimental and computational enthalpies of formation of methyl 2- and 4-methoxybenzoates. Finally, we discuss the enthalpic effects, as a function of the relative position of the methoxy and methyl groups, upon the benzoate base structure.

show abstract

Section: ■ Experimental Methodsmentioning

confidence: 99%