Experimental and computational thermodynamic study of ortho-, meta-, and para-methylbenzamide

• Type: Article in International Scientific Journal
• Date: 2012

Authors

Ana R R P Almeida (Author) Other; Agostinha A R Matos (Author) FCUP; Manuel J S Monte (Author) FCUP; Victor M F Morais (Author) ICBAS

Journal

Title: Journal of Chemical Thermodynamics

Vol. 47

Pages: 81-89

ISSN: 0021-9614

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 15 Citations

Scopus - 15 Citations

Scientific classification

FOS: Engineering and technology > Mechanical engineering

Other information

Authenticus ID: P-002-BY3

DOI: 10.1016/j.jct.2011.09.024

Abstract (EN): The Knudsen mass-loss effusion technique was used to measure the vapour pressures of the three crystalline isomers of methylbenzamide. From the temperature dependence of the vapour pressures, the standard molar enthalpies of sublimation and the enthalpies of the intermolecular hydrogen bonds N-H center dot center dot center dot O were calculated. The temperature and molar enthalpy of fusion of the studied isomers were measured using differential scanning calorimetry. The values of the standard (p degrees = 0.1 MPa) molar enthalpy of formation in the crystalline phase, at T = 298.15 K, of the compounds studied were derived from their standard massic energies of combustion measured by static-bomb combustion calorimetry. From the experimental values, the standard molar enthalpies of formation in the gaseous phase, at T = 298.15 K, were calculated and compared with the values estimated by employing computational calculations that were conducted using different quantum chemical methods: G3( MP2), G3, and CBS-QB3. Good agreement between experimental and theoretical results is verified. The aromaticity of the compounds has been evaluated through nucleus independent chemical shifts (NICS) calculations.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 9