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VALUES OF (DeltafHo298.15)(g) AND (So298.15)(g) OF THE SEVERAL N,N-ETHYLENEBISALKANEAMIDES CALCULATED USING RB3LYP/6-31G(D,P) AND CBS-4M APPROACHES, AND THEIR CORRELATION DEPENDENCIESстатья
Информация о цитировании статьи получена из
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Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 5 июня 2017 г.
- Автор: Poskrebyshev G.A.
- Журнал: Computational and theoretical chemistry
- Том: 1105
- Год издания: 2017
- Издательство: Elsevier
- Местоположение издательства: United States
- Первая страница: 77
- Последняя страница: 88
- DOI: 10.1016/j.comptc.2017.02.019
- Аннотация: In the present work, the thermochemical properties of the several N,N′-ethylenbisalkaneamides are calculated using RB3LYP/6-31G(d,p), UB3LYP/6-311++G(d,p), CBS-4M and CBS-Q approaches. The values of standard enthalpies of their formation ((ΔfHo 298.15)(g)) are calculated using thermochemistry of the isodesmic reactions as well as using the group additivity methods. Due to the high uncertainty in the values of (ΔfHo 298.15)(g) of the high atomic molecules, calculated using different approaches, the simple methodology for determination of (ΔfHo 298.15)(g) values of compounds with more than 16 “heavy” atoms (C, N and O) is proposed. This methodology is based on the extrapolation of the linear dependence of results of the CBS-4M and RB3LYP/6-31G(d,p) calculations. Reliability of the values of (ΔfHo 298.15)(g), determined using this methodology, is comparable with the results of CBS-4M calculations. The following expression for the determination of (ΔfHo 298.15)CBS-4M = 0.45 + 1.023 × (ΔfHo 298.15)RB3LYP describes well the values of (ΔfHo 298.15)(g) of amides, n-alkanes and N,N′-ethylenbisalkaneamides, calculated using the CBS-4M approach. The values of (ΔfHo 298.15)CBS-4M = −578.9 ± 7 and −1128.8 ± 7 kJ/mol, determined using this expression, and the values of (ΔfHo 298.15)RB3LYP, calculated, respectively, for (C4H9C(O)NHCH2)2 and (C17H35C(O)NHCH2)2, agree with those values determined using the group additivity method (respectively, equal to −568.8 and −1126.8 kJ/mol). Values of (S°298.15)(g) of the considered N,N′-ethylenbisalkaneamides are also calculated in the present work. It's shown that tabulated values of (S°298.15)(g) of the n-alkanes and n-alkaneamines depend linearly upon those values, calculated using RB3LYP/6-31G(d,p) quantum mechanics (QM) approach. In both cases, the same values of slope of these dependencies are observed. As a result, the following expression for determination of S°298.15((CnH2n+1C(O)NHCH2)2) = −108.2 + 1.266 × S°298.15(((CnH2n+1C(O)NHCH2)2)RB3LYP) and the method for determination of (S°298.15)(g) values of high atomic compounds that belong to the same homologous series is proposed. The values of S°298.15((CnH2n+1C(O)NHCH2)2), calculated in the present work for considered compounds are: 383.5 (n = 0), 481.4 (n = 1), 554.8 (n = 2), 630 (n = 3), 712.3 (n = 4) и 1709.9 (n = 17) J/(mol K). © 2017 Elsevier B.V.
- Добавил в систему: Поскрёбышев Григорий Анатольевич