Thermodynamic study on hydroxybenzaldehyde derivatives: 3- and 4-Hydroxybenzaldehyde isomers and 3,5-di-tert-butyl-2-hydroxybenzaldehyde

Reported in the present work are the values of the gaseous standard (p∘=0.1MPa) molar enthalpies of formation of 3-hydroxybenzaldehyde (3HBA), 4-hydroxybenzaldehyde (4HBA), and 3,5-di-tert-butyl-2-hydroxybenzaldehyde (3,5DTBHBA), at T = 298.15 K. For the three compounds, the values were derived from measurements of the standard molar energies of combustion of the crystalline compounds, using a static bomb calorimeter {ΔcHm∘(3HBA)=-(3298.3±1.3)kJ·mol-1,ΔcHm∘(4HBA)=-(3291.8±0.9)kJ·mol-1,ΔcHm∘(3,5DTBHBA)=-(8502.6±2.9)kJ·mol-1}, together with the standard molar enthalpies of sublimation, at T = 298.15 K, derived from the vapour pressures measured at different temperatures using the Knudsen effusion technique {ΔcrgHm∘(3HBA)=(100.1±0.6)kJ·mol-1,ΔcrgHm∘(4HBA)=(102.5±0.5)kJ·mol-1,ΔcrgHm∘(3,5DTBHBA)=(96.0±0.5)kJ·mol-1}.