Thermophysical properties of some nonlinear polyphenyls


A. Rodrigues1, M. Rocha1, M. Bastos1, L. Gomes2 and L. Santos1

1Centro de Investigacao em Quimica, Faculdade de Ciencias da Universidade do Porto, Porto, Portugal
2CBFC, Faculdade de Ciências da Saúde, Universidade Fernando Pessoa, Porto, Portugal

Keywords: nonlinear polyphenyls, sublimation, vapour pressures
property: vapour pressures, enthalpies, entropies and gibbs energies of sublimation
material: nonlinear polyphenyls

The polyphenyls are very promising organic materials with interesting thermal and electric properties, that makes them potential organic semiconductors.[1].This work focuses on the thermophysical and structural study of four nonlinear polyphenyls: o-quarterphenyl,m-quarterphenyl, o-quinquephenyl and m-quinquephenyl. The temperatures and the standard molar enthalpies of fusion were determined in a power compensation DSC, and the standard molar entropies of fusion were derived. The heat capacities of the compounds were measured by a precise Drop heat capacity calorimeter developed by Wadsö[2-3] which was now adapted at our Laboratory, both as regarding temperature sensors, electronics and to enable the use of computer data acquisition in a user-friendly environment. The vapour pressures at different temperatures were measured using the Knudsen effusion method incorporated with a quartz crystal microbalance. From the obtained results the standard molar enthalpies, entropies and Gibbs energies of sublimation were derived. The comparative analysis of the ortho and meta positions effect in the thermophysical properties will be done based in the supramolecular structural data. Fundação para a Ciência e Tecnologia (FCT) and Programa Operacional Ciência e Inovação 2010 (POCI 2010) supported by the European Community Fund FEDER is acknowledge for the financial support to Project PTDC/QUI-QUI/102814/2008. M. A. A. Rocha acknowledge the financial support from F.C.T. for the award of a research grant, with reference SFRH/BD/60513/2009.

References
  1. C. Li, M. Liu, N.G. Pschirer, M.Baumgarten and K. Müller, Chem.Rev. 110, 6817 (2010)

  2. J. Konicek, J. Suurkuusk, I. Wadsö, Chemica Scripta 1, 217 (1971)

  3. J. Suurkuusk, I. Wadsö, J. Chem. Thermodynamics 6, 667 (1974)

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