Experimental thermochemical study of two 2-alkylbenzimidazole isomers (alkyl=propyl and isopropyl)

• Published in: The Journal of chemical thermodynamics Vol. 36; no. 6; pp. 533 - 539
• Main Authors: da Silva, Manuel A.V.Ribeiro, da Silva, Maria D.M.C.Ribeiro, Amaral, Luı́sa M.P.F., Jiménez, Pilar, Roux, Maria Victoria, Dávalos, Juan Z., Temprado, Manuel, Cabildo, Pilar, Claramunt, Rosa M., Elguero, José, Mó, Otilia, Yáñez, Manuel
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.06.2004; Elsevier
• Subjects: 2-Propylbenzimidazole and 2-Isopropylbenzimidazole; Chemical thermodynamics; Chemistry; Elements, mineral and organic compounds; Enthalpies of combustion; Enthalpies of formation; Enthalpies of sublimation; Exact sciences and technology; General and physical chemistry; Thermodynamic properties; Enthalpies of sublimation; 2-Propylbenzimidazole and 2-Isopropylbenzimidazole; Enthalpies of combustion; Enthalpies of formation; Heat of combustion; Differential scanning calorimetry; Knudsen effusion; Nitrogen heterocycle; Heat of sublimation; Experimental study; Isomer; Benzimidazole derivatives; Thermal analysis; Thermodynamic properties; Heat of formation
• ISSN: 0021-9614; 1096-3626
• DOI: 10.1016/j.jct.2004.03.005

This paper reports the values of the standard ( p ∘=0.1 MPa) molar enthalpy of formation in the condensed, at T=298.15 K, for 2-R-benzimidazoles (R=propyl, isopropyl), derived from, the respective enthalpies of combustion in oxygen, measured by static bomb combustion calorimetry and the standard molar enthalpies of sublimation, at T=298.15 K, obtained using Calvet microcalorimetry in the case of 2-isopropylbenzimidazole and, by the variation of vapour pressures, determined by the Knudsen effusion technique, with temperatures between (344 and 365) K for 2-propylbenzimidazole. Heat capacities, in the temperature ranges from T=268 K to near their respective melting temperatures, T=421 K for 2-propylbenzimidazole and T=464 K for 2-isopropylbenzimidazole, were measured with a differential scanning calorimeter. These values were used to derive the standard molar enthalpies of formation, of the two 2-benzimidazole derivatives, in gaseous phase.