Low-temperature heat capacities and standard molar enthalpy of formation of 4-(2-aminoethyl)-phenol (C₈H₁₁NO)

This paper reports that low-temperature heat capacities of 4-(2-aminoethyl)-phenol (C_8H_11NO) are measured by a precision automated adiabatic calorimeter over the temperature range from 78 to 400 K. A polynomial equation of heat capacities as a function of the temperature was fitted by the least square method. Based on the fitted polynomial, the smoothed heat capacities and thermodynamic functions of the compound relative to the standard reference temperature 298.15 K were calculated and tabulated at the interval of 5 K. The energy equivalent, \varepsilon_\rm calor, of the oxygen-bomb combustion calorimeter has been determined from 0.68 g of NIST 39i benzoic acid to be \varepsilon _\rm calor=(14674.69\pm 17.49)J \cdot K^ - 1. The constant-volume energy of combustion of the compound at T=298.15 K was measured by a precision oxygen-bomb combustion calorimeter to be \Delta _\rm cU=--(32374.25\pm 12.93)J \cdot g^ - 1. The standard molar enthalpy of combustion for the compound was calculated to be \Delta _\rm c H_\rm m^\ominus = - (4445.47\pm 1.77)\,\rm kJ \cdot \mboxmol^ - 1 according to the definition of enthalpy of combustion and other thermodynamic principles. Finally, the standard molar enthalpy of formation of the compound was derived to be \Delta _\rm f H_\rm m^\ominus (\rm C_8 H_11 NO,s) = - (274.68\pm 2\mbox.06)\,kJ \cdot \mboxmol^\rm - 1, in accordance with Hess law.