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Title: | Low-temperature heat capacity and standard molar enthalpy of formation of crystalline (S)–(+)–Ibuprofen (C₁₃H₁₈O₂)(s) |
Authors: | Di, You-Ying Ye, Chun-Tian Tan, Zhi-Cheng Zhang, Guo-Ding |
Issue Date: | Jun-2007 |
Publisher: | CSIR |
Abstract: | Low-temperature heat capacities of the compound,(S)–(+)–Ibuprofen (C₁₃H₁₈O₂), have been measured by a precision automated adiabatic calorimeter in the temperature range 78 – 348 K. The experimental molar heat capacities in the temperature range 78 – 345 K have been fitted to a polynomial equation. The smoothed heat capacities and thermodynamic functions, (HT - H₂₉₈․₁₅ĸ) and (ST - S₂₉₈․₁₅ĸ), of the compound have been calculated by the heat-capacity polynomial equation. The constant-volume energy of combustion of the compound, has been found to be ΔUc (C₁₃H₁₈O₂, s) = – (7136.94 ± 4.74) kJmol⁻¹ by means of a home-made oxygen-bomb combustion calorimeter at T = 298.15 ± 0.001 K. The standard molar enthalpy of combustion of the sample has been calculated to be ΔcHmº (C₁₃H₁₈O₂, s) = – (7145.62 ± 4.74) kJmol⁻¹, from the constant-volume combustion energy. The standard molar enthalpy of formation of the compound has been derived, ΔքHmº (C₁₃H₁₈O₂, s) = – (542.48 ± 5.05) kJmol⁻¹, from the combination of the data of standard molar enthalpy of combustion of the compound with other auxiliary thermodynamic quantities through a Hess thermochemical cycle. |
Page(s): | 947-951 |
URI: | http://hdl.handle.net/123456789/1210 |
ISSN: | 0376-4710 |
Appears in Collections: | IJC-A Vol.46A(06) [June 2007] |
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File | Description | Size | Format | |
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IJCA 46A(6) (2007) 947-951.pdf | 173.12 kB | Adobe PDF | View/Open |
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