Low-temperature heat capacities and standard molar enthalpy of formation of 4-(2-aminoethyl)-phenol (C8H11NO)
Di You-Ying(邸友莹)a)†, Kong Yu-Xia(孔玉霞)a), Yang Wei-Wei(杨伟伟)a), and Tan Zhi-Cheng(谭志诚)b)
a College of Chemistry and Chemical Engineering, Liaocheng University, Liaocheng 252059, China; b Thermochemistry Laboratory, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
Abstract This paper reports that low-temperature heat capacities of 4-(2-aminoethyl)-phenol (C$_{8}$H$_{11}$NO) 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 $\Delta _{\rm c}U$=--(32374.25$\pm $12.93)J$ \cdot $g$^{ - 1}$. The standard molar enthalpy of combustion for the compound was calculated to be $\Delta _{\rm c} H_{\rm m}^\ominus = { - }(4445.47\pm 1.77)\,{\rm kJ} \cdot \mbox{mol}^{{ - 1}}$ 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 $\Delta _{\rm f} H_{\rm m}^\ominus (\rm C_8 H_{11} NO,s){ = - (274.68}\pm 2\mbox{.06)\,kJ} \cdot \mbox{mol}^{{\rm - 1}}$, in accordance with Hess law.
Received: 04 January 2008
Revised: 24 January 2008
Accepted manuscript online:
Fund: Project
supported by the National Natural Science Foundation of China
(Grant No 20673050).
Cite this article:
Di You-Ying(邸友莹), Kong Yu-Xia(孔玉霞), Yang Wei-Wei(杨伟伟), and Tan Zhi-Cheng(谭志诚) Low-temperature heat capacities and standard molar enthalpy of formation of 4-(2-aminoethyl)-phenol (C8H11NO) 2008 Chin. Phys. B 17 3276
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