Thermochemistry of hydroxymethylphenol isomers

• Type: Article in International Scientific Journal
• Date: 2010

Authors

da Silva, MAVR (Author) FCUP; Ana I M C L Lobo Ferreira (Author) FCUP

Journal

Title: Journal of Thermal Analysis and Calorimetry

Vol. 100

Pages: 447-455

ISSN: 1388-6150

Publisher: Springer Nature

Indexing

ISI Web of Knowledge - 5 Citations

Scopus - 4 Citations

Scientific classification

FOS: Engineering and technology > Chemical engineering

CORDIS: Physical sciences > Chemistry > Physical chemistry

Other information

Authenticus ID: P-003-73W

DOI: 10.1007/s10973-009-0647-6

Abstract (EN): 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.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 9