Enthalpy of formation and hydrogen bonded dimerization of furfurylamine: Experimental and computational study

• Published in: Thermochimica acta 2023-07, Vol.725, p.179536, Article 179536
• Main Authors: Lukyanova, Vera A., Tarazanov, Sergey V., Dorofeeva, Olga V., Druzhinina, Anna I., Ilin, Dmitriy Yu
• Format: Article
• Language: English
• Subjects: Combustion energy; Enthalpy of dimerization; Enthalpy of formation; Furfurylamine; Quantum chemical calculations
• ISSN: 0040-6031; 1872-762X
• DOI: 10.1016/j.tca.2023.179536

•Enthalpy of formation of liquid furfurylamine was determined calorimetrically.•Gas-phase enthalpy of formation was estimated from quantum chemical calculations.•Strong dimerization of furfurylamine in the vapor was predicted theoretically.•Dimerization was supported by the comparison of ΔfH298∘(l) and ΔfH298∘(g) values. The combustion energy and standard molar enthalpy of formation of liquid furfurylamine were determined using an isoperibol calorimeter with a static bomb. The theoretical calculations were used for the interpretation of experimental calorimetric result. The DLPNO-CCSD(T1)/CBS method in conjunction with isodesmic-type reactions was used to calculate the gas-phase enthalpy of formation of this compound. At the same level of theory, the interconversion of the gauche and anti conformers of furfurylamine and the N–H⋯N hydrogen bonding between them leading to the association into dimeric units were studied. The calculated values of equilibrium and rate constants for reaction gauche → anti and enthalpy of dimerization of two conformers suggest that the gaseous furfurylamine exists predominantly in the dimeric form. An additional support for the strong association of furfurylamine in the vapor phase was obtained from comparison of the enthalpies of formation in liquid and gaseous states: the consistency between these two values was achieved only when a correction for dimerization was applied. [Display omitted]