Fluorination effect on the thermodynamic properties of long-chain hydrocarbons and alcohols

• Tipo: Artigo em Revista Científica Internacional
• Data: 2016

Autores

Adélio Mendes (Autor) FEUP; José C. S. Costa (Autor) FCUP; Carlos F. R. A. C. Lima (Autor) Outra; Luís M. N. B. F. Santos (Autor) FCUP

Revista

Título: Journal of Chemical Thermodynamics

Vol. 102

Páginas: 378-385

ISSN: 0021-9614

Editora: Elsevier

Indexação

ISI Web of Knowledge - 12 Citações

ISI Web of Science

Scopus - 12 Citações

Classificação Científica

CORDIS: Ciências Tecnológicas

Projetos Associados

LEPABE - Laboratório de Engenharia de Processos, Ambiente, Biotecnologia e Energia

Outras Informações

ID Authenticus: P-00K-PV0

DOI: 10.1016/j.jct.2016.07.037

Abstract (EN): Structural and thermodynamic insights are reported for the series of fluorinated alcohols {oFTOH; CF3(CF2)nCH2OH, with n = 5–12}, with the objective of comparing the phase behaviour of perfluorinated compounds with the analogous linear alkanes and alcohols. As expected the higher vibrational contribution of the –CF2– groups contributes for the higher heat capacities of the perfluorinated compounds. Concerning the fusion/sublimation equilibria, fluorination of the alcohols decreases DH and DS of phase transitions. Compared to the regular –CH2– alkyl chain structure, the less symmetric –CF2– spiral conformation is characterized by a less efficient molecular alignment in crystal packing, thus explaining the lower DH. The lower internal rotational barrier associated with the –CH2– alkyl chains of n-alkanes/alcohols, when compared to –CF2– chains, contributes to the larger values of DS observed. Regarding the vaporization equilibria, fluorination leads to greater values of DS, which are explained by the larger translational entropy of the heavier perfluoroalcohols, an effect that is more important in the gas than in the liquid phase.

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 8