resumo
A phase transition study, including vapour pressure determinations of odd fluorotelomer alcohols {oFTOH; CF3(CF2)(n)CH2OH, with n = 5 to 9}, is reported in order to explore the effect of the successive introduction of -CF2- groups into the molecule on the thermodynamic properties related to (solid + liquid, solid + gas, and liquid + gas) equilibria. An odd-even effect on the thermodynamic parameters of fusion and sublimation was observed in the homologous series of odd fluorotelomer alcohols indicating an increase of the stability in the crystal packing for the members with an odd number of carbon atoms. The vaporization parameters of o-FTOH were compared with the literature data for their alkane analogues and the results showed a higher volatility of liquid fluorotelomer alcohols than their congeners. The higher molecular conformation restriction of perfluorinated alcohols and/or the higher molar mass seems to contribute to their higher entropy of vaporization which drives the volatility of the 1H,1H-perfluorinated alcohols. (C) 2012 Elsevier Ltd. All rights reserved.
palavras-chave
ALIPHATIC DICARBOXYLIC-ACIDS; HIGHLY FLUORINATED COMPOUNDS; MELTING-POINT ALTERNATION; VAPOR-PRESSURE; PERFLUORINATED COMPOUNDS; PARTITIONING BEHAVIOR; AQUEOUS SOLUBILITY; ORGANIC-COMPOUNDS; SOILS; WATER
categoria
Thermodynamics; Chemistry
autores
Costa, JCS; Fulem, M; Schroder, B; Coutinho, JAP; Monte, MJS; Santos, LMNBF
nossos autores
Bernd Schroder
Bolseiro de pós-Doutoramento
agradecimentos
J.C.S. Costa and B. Schroder acknowledge Fundacao para a Ciencia e Tecnologia (FCT) and the European Social Fund (ESF) under the third Community Support Framework (CSF) for the award of Ph.D. Research Grant SFRH/BD/74367/2010, and a Post-Doctoral Grant, SFRH/BPD/38637/2007, respectively.