What is the enthalpy of formation of pyrazine-2-carboxylic acid?

• Autores: Duarte, Darío Jorge Roberto; Miranda, Margarida S.; Liebman, Joel F.
• Año de publicación: 2016
• Idioma: inglés
• Tipo de recurso: artículo
• Fuente: Journal of Chemical Thermodynamics, 2016, vol. 97, p. 261-263.
• Materia: Pyrazine; Carboxylic acid; Enthalpy of formation
• Institución: Universidad Nacional del Nordeste

Fil: Duarte, Darío Jorge Roberto. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas y Naturales y Agrimensura; Argentina.
Fil: Miranda, Margarida S. Universidade do Porto. Faculdade de Ciências; Brazil.
Fil: Liebman, Joel F. University of Maryland. Department of Chemistry and Biochemistry; Estados Unidos.
There are two contemporary conflicting, indeed, incompatible determinations of measurements of the enthalpies of combustion and of formation of pyrazine-2-carboxylic acid in the literature, ( 2268.0 ± 0.9 and 271.2 ± 1.1 kJ mol 1) and ( 2211.4 ± 0.9 and 327.8 ± 1.1 kJ mol 1). The current paper discusses these two sets of values and from the use of a measurement of the enthalpy of sublimation, a newly evaluated enthalpy of formation of pyrazine itself, and of the quantum chemical calculations at the G3(MP2)//B3LYP level, the former results are accepted and the derived gas phase enthalpy of formation, (167.6 ± 3.1) kJ mol 1, suggested.