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Author(s): Adélio Mendes
José C. S. Costa
Carlos F. R. A. C. Lima
Luís M. N. B. F. Santos
Title: Fluorination effect on the thermodynamic properties of long-chain hydrocarbons and alcohols
Issue Date: 2016
Abstract: 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 perfluorinatedcompounds 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 phasetransitions. Compared to the regular -CH2- alkyl chain structure, the less symmetric -CF2- spiralconformation is characterized by a less efficient molecular alignment in crystal packing, thus explainingthe lower DH. The lower internal rotational barrier associated with the -CH2- alkyl chains ofn-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 explainedby the larger translational entropy of the heavier perfluoroalcohols, an effect that is more important inthe gas than in the liquid phase.
Subject: Ciências Tecnológicas
Technological sciences
Related Information: info:eu-repo/grantAgreement/FCT - Fundação para a Ciência e Tecnologia/Projetos Estratégicos/UID/EQU/00511/2013 - POCI-01-0145-FEDER-006939/Laboratório de Engenharia de Processos, Ambiente, Biotecnologia e Energia/LEPABE
Document Type: Artigo em Revista Científica Internacional
Rights: restrictedAccess
Appears in Collections:FCUP - Artigo em Revista Científica Internacional
FEUP - Artigo em Revista Científica Internacional

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