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Author(s): Ana L R Silva
Alvaro Cimas
Nuno Vale
Paula Gomes
Manuel J S Monte
Maria D M C R Ribeiro da Silva
Title: Experimental and computational study of the energetics of hydantoin and 2-thiohydantoin
Issue Date: 2013
Abstract: This work reports an experimental and a theoretical study of two imidazolidine derivatives, hydantoin (CAS No. 461-72-3) and 2-thiohydantoin (CAS No. 503-87-7). The standard (p degrees = 0.1 MPa) molar energies of combustion of hydantoin and 2-thiohydantoin were measured by static and rotating bomb combustion calorimetry, respectively. The standard molar enthalpies of sublimation, at T = 298.15 K, were derived from the temperature dependence of the vapour pressures of these compounds, measured by the Knudsen-effusion technique, and from high temperature Calvet microcalorimetry. The conjugation of these experimental results enables the calculation of the standard molar enthalpies of formation in the gaseous state, at T = 298.15 K, which are discussed in terms of structural contributions. We have also estimated the gas-phase enthalpy of formation from high-level ab initio molecular orbital calculations at the G3MP2B3 level of theory, being the computed values in good agreement with the experimental ones. Furthermore, this composite approach was also used to obtain information about the gas-phase basicities, proton and electron affinities and adiabatic ionization enthalpies.
Subject: Química
Chemical sciences
Scientific areas: Ciências exactas e naturais::Química
Natural sciences::Chemical sciences
Document Type: Artigo em Revista Científica Internacional
Rights: openAccess
Appears in Collections:FCUP - Artigo em Revista Científica Internacional

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