Ribeiro da Silva Manuel A V, Ferreira Ana I M C L, Gomes José R B
Centro de Investigação em Química, Departamento de Química, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, 687, P-4169-007, Porto, Portugal.
J Phys Chem B. 2007 Jun 14;111(23):6444-51. doi: 10.1021/jp071232o. Epub 2007 May 23.
The standard (po = 0.1 MPa) molar enthalpies of formation in the condensed phase of seven isomers of fluoromethylaniline were derived from the standard molar energies of combustion, in oxygen, to yield CO2(g), N2(g) and HF.10H2O(l), at T = 298.15 K, measured by rotating bomb combustion calorimetry. The standard molar enthalpies of vaporization or sublimation of these compounds, also at T = 298.15 K, were determined using Calvet microcalorimetry, while the enthalpies of fusion of the solid compounds were determined by differential scanning calorimetry. The standard molar enthalpies of formation in the gaseous phase, at T = 298.15 K, were derived from the former two experimental quantities. G3MP2//B3LYP calculations were performed for all possible fluoromethylanilines allowing the estimation of data for the isomers that were not studied experimentally. The Cox scheme was applied with two different approaches for the estimation of the standard molar enthalpies of formation of all the isomers studied, and this led to the conclusion that the literature values for the enthalpies of formation of the meta and para isomers of methylaniline seem to be not reliable. Further G3MP2//B3LYPs calculations on the methylaniline isomers yielded new values for the standard molar enthalpies of formation of the isomers of methylaniline, which have been tested under the Cox scheme, resulting in better estimates.
通过旋转弹燃烧量热法测量，在T = 298.15 K下，氟甲基苯胺的七种异构体在凝聚相中的标准（po = 0.1 MPa）摩尔生成焓由其在氧气中燃烧生成CO2(g)、N2(g)和HF·10H2O(l)的标准摩尔能量推导得出。这些化合物在T = 298.15 K时的标准摩尔汽化焓或升华焓使用卡尔维量热法测定，而固体化合物的熔化焓通过差示扫描量热法测定。在T = 298.15 K时，气相中的标准摩尔生成焓由前两个实验量推导得出。对所有可能的氟甲基苯胺进行了G3MP2//B3LYP计算，从而可以估算未进行实验研究的异构体的数据。采用Cox方法，用两种不同的途径估算了所有研究异构体的标准摩尔生成焓，得出结论：文献中甲基苯胺间位和对位异构体生成焓的值似乎不可靠。对甲基苯胺异构体进一步进行G3MP2//B3LYP计算，得出了甲基苯胺异构体标准摩尔生成焓的新值，这些值在Cox方法下进行了检验，得到了更好的估算结果。
