Thermochemical studies on two alkyl-bulky substituted xanthene derivatives: 9,9-dimethylxanthene and 2,7-di-tert-butyl-9,9-dimethylxanthene
authors Freitas, VLS; Gomes, JRB; da Silva, MDMCR
nationality International
source JOURNAL OF CHEMICAL THERMODYNAMICS
author keywords Combustion calorimetry; Enthalpy of sublimation; Enthalpy of formation; Vapour pressure; 2,7-Di-tert-butyl-9,9-dimethylxanthene conformers; Xanthene derivatives
keywords plus DIFFERENTIAL SCANNING CALORIMETERS; THERMODYNAMIC PROPERTIES; FUNCTIONAL-GROUPS; VAPOR-PRESSURES; ENERGETICS; CALIBRATION; ENERGIES; EFFUSION; HYDROCARBONS; ENTHALPIES
abstract Thermodynamic properties of 9,9-dimethylxanthene and 2,7-di-tert-butyl-9,9-dimethylxanthene for the condensed and gas states were derived from experimental and computational studies. Static-bomb combustion calorimetry, vacuum drop microcalorimetry and the Knudsen effusion techniques were used. Computational calculations of the enthalpies of hypothetical reactions in the gaseous phase, using the G3(MP2)//B3LYP composite method, were performed for the two xanthene derivatives. Natural bond orbital (NBO) calculations were also performed to ascertain the structure and reactivity of these compounds. The energetic effects caused by replacing hydrogen atoms in the xanthene moiety by methyl and tertbutyl groups yielding 9,9-dimethylxanthene and 2,7-di-tert-butyl-9,9-dimethylxanthene species were determined from direct comparison of their standard (p degrees = 0.1 MPa) molar enthalpies of formation in the gaseous phase, at T=298.15 K. (C) 2016 Elsevier Ltd.
publisher ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD
issn 0021-9614
year published 2017
digital object identifier (doi) 10.1016/j.jct.2016.11.020
web of science category Thermodynamics; Chemistry, Physical
subject category Thermodynamics; Chemistry
unique article identifier WOS:000392352900018
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  impact metrics
times cited (wos core): 0
journal impact factor (jcr 2015): 2.679
5 year journal impact factor (jcr 2015): 2.531
category normalized journal impact factor percentile (jcr 2015): 75.206
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