Thermochemistry of sesquiterpene lactone argolide

Abstract

The enthalpies of dissolution of argolide (C₁₅H₂₀O₃) in 96% ethanol are determined by isothermal calorimetry at 298.15 K and different dilutions of 1: 18 000, 1: 36 000, and 1: 72 000 (by mole). The standard enthalpy of dissolution of argolide in 96% ethanol is calculated from the obtained data: (86 ± 17) kJ mol⁻¹. The temperature dependence of heat capacity of C₁₅H₂₀O₃ is studied by means of dynamic calorimetry. An equation is derived to describe the С_p⁰~ f (Т) dependence, and the standard heat capacity at 298.15 K is found to be (393 ± 13) J mol⁻¹ K⁻¹. The enthalpies of combustion, fusion and formation of argolide are calculated via approximation.