Please use this identifier to cite or link to this item: https://hdl.handle.net/10216/95171
Author(s): da Silva, MAVR
Ana I M C L Lobo Ferreira
Title: Thermochemistry of hydroxymethylphenol isomers
Issue Date: 2010
Abstract: The standard (p(o) = 0.1 MPa) molar enthalpies of formation in the crystalline state of the 2-,3- and 4-hydroxymethylphenols, Delta(f)H(m)(o)(cr) = -(377.7 +/- 1.4) kJ mol(-1), Delta(f)H(m)(o)(cr) = -(383.0 +/- 1.4) kJ mol(-1) and Delta(f)H(m)(o)(cr) = -(382.7 +/- 1.4) kJ mol(-1), respectively, were derived from the standardmolar energies of combustion, in oxygen, to yield CO(2)(g) and H(2)O(l), at T = 298.15 K, measured by static bomb combustion calorimetry. The Knudsen mass-loss effusion technique was used to measure the dependence of the vapour pressure of the solid isomers of hydroxymethylphenol with the temperature, from which the standard molar enthalpies of sublimation were derived using the Clausius-Clapeyron equation. The results were as follows: Delta(g)(cr)H(m)(o) = (99.5 +/- 1.5) kJ mol(-1), Delta(g)(cr)H(m)(o) = (116.0 +/- 3.7) kJ mol(-1) and D(cr)(g)H(m)(o) = (129.3 +/- 4.7) kJ mol(-1), for 2-, 3- and 4-hydroxymethylphenol, respectively. From these values, the standard molar enthalpies of formation of the title compounds in their gaseous phases, at T = 298.15 K, were derived and interpreted in terms of molecular structure. Moreover, using estimated values for the heat capacity differences between the gas and the crystal phases, the standard (p(o) = 0.1 MPa) molar enthalpies, entropies and Gibbs energies of sublimation, at T = 298.15 K, were derived for the three hydroxymethylphenols.
Subject: Química física, Engenharia química
Physical chemistry, Chemical engineering
Scientific areas: Ciências da engenharia e tecnologias::Engenharia química
Engineering and technology::Chemical engineering
URI: https://hdl.handle.net/10216/95171
Document Type: Artigo em Revista Científica Internacional
Rights: restrictedAccess
Appears in Collections:FCUP - Artigo em Revista Científica Internacional

Files in This Item:
File Description SizeFormat 
48413.pdf
  Restricted Access
281.23 kBAdobe PDF    Request a copy from the Author(s)


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.