The energetics of isomeric benzoxazine diones: isatoic anhydride revisited

• Type: Article in International Scientific Journal
• Date: 2004

Authors

Matos, MAR (Author) FCUP; Miranda, MS (Author) Other; Morais, VMF (Author) ICBAS; Liebman, JF (Author) Other

Journal

Title: Organic and Biomolecular Chemistry

Vol. 2

Pages: 1647-1650

ISSN: 1477-0520

Publisher: Royal Society of Chemistry

Indexing

ISI Web of Knowledge - 13 Citations

Scopus - 14 Citations

Scientific classification

FOS: Natural sciences > Chemical sciences

Other information

Authenticus ID: P-000-DB4

DOI: 10.1039/b402801e

Abstract (EN): The standard (pdegrees = 0.1 MPa) molar enthalpy of formation of crystalline 2H-1,3-benzoxazine-2,4(3H)dione was measured, at T = 298.15 K, by static bomb calorimetry and the standard molar enthalpy of sublimation, at T = 298.15 K, was obtained using Calvet microcalorimetry. These values were used to derive the standard molar enthalpy of formation in the gaseous phase, T = 298.15 K, of -(401.0 +/- 3.5) kJ mol(-1). The standard molar enthalpy of sublimation of isatoic anhydride was recalculated, and our recommended experimental value for the standard molar enthalpy of formation in the gaseous phase, T = 298.15 K, is -(406.2 +/- 3.4) kJ mol(-1). Density functional calculations for the two isomers 2H-1,3-benzoxazine-2,4(3H)dione and isatoic anhydride, in which the ring nitrogen and oxygen have been transposed, confirm the experimental evidence of nearly identical thermochemical stability for these isomers.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 4