3rd meeting of young researchers at UP 1 - IJUP - Universidade do ...

Energetic study of fluorene
Sónia Pinto, Maria D.M.C. Ribeiro da Silva
Centro de Investigação em Química, Departamento de Química, Faculdade de Ciências,
Universidade do Porto, Rua do Campo Alegre, 687, P-4169-007, Porto, Portugal
Polycyclic aromatic hydrocarbons (PAHs) and some of their derivatives represent a complex
group of important environmental pollutants, originated by a wide variety of natural and
anthropogenic sources, and constitute a class of compounds with relevant negative impact for
health [1]. On the other hand, PAHs are having an increasing interest on the field of organic
electronics due to their good performance as active components in a new generation of
electronic devices, as organic light-emitting diodes and organic photovoltaic cells.
In order to correlate molecular energetic data with the structural characteristics of the
molecules, experimental and computational thermochemical studies of different classes of
aromatic compounds have been, for a long time, one of the aims of our Research Group. The
lack of reliable energetic data for polycyclic aromatic hydrocarbons (PAHs) and their
derivatives justifies our attention to the present theme, involving the study of thermodynamic
properties of fluorene and its derivatives, in order to get key values not available from the
literature.
As the purification of these compounds is difficult, so far
only the fluorene has been purified with enough purity to
perform the thermochemical measurements. We will report
now the corresponding energy of combustion, obtained from
static bomb calorimetry, and the derived value of the
crystalline standard molar enthalpy of formation.
The vapour pressures of fluorene will be measured in
near future, as a function of the temperature, using the
method [2], from which the standard molar enthalpy of
sublimation, at T = 298.15 K, will be derived using the
Figure 1 – Chemical
structure of fluorene
the
static
Clarke-Glew equation. The combination of the values of standard molar enthalpy of formation
in the crystalline phase with the standard molar enthalpy of sublimation, will allow the
calculation of the standard molar enthalpy of formation of fluorene, in the gaseous phase, at T
= 298.15 K.
References:
[1]- Verevkin, S. P., (2004), Vapor pressure measurements on fluorene and methyl-fluorenes, Elsevier,
225, 145-152.
[2]- Monte, M. J. S., Santos, L. M. N. B. F., Sousa, C. A. D., Fulem, M., (2008), Vapor pressures of
solid and liquid xanthene and phenoxathiin from effusion and static studies, J. Chem. Eng. Data, 53,
1922-1926.
Acknowledgments:
Thanks are due to Vera Freitas and Ana Lobo for their support on the development of the experimental work.
3 rd meeting of young researchers at UP 359