Thermodynamic investigation of several natural polyols (IV): Heat capacities and thermodynamic properties of adonitol

Abstract

Adonitol was investigated by adiabatic calorimetry (AC), differential scanning calorimetry (DSC), thermogravity analysis (TGA) and oxygen-bomb combustion calorimetry. The heat capacity was precisely measured in the temperature range from 78 to 400 K by means of a small sample automated adiabatic calorimeter. The melting temperature, the molar enthalpy and entropy of this transition were determined to be T = 369.08 ± 0.45 K, 36.42 ± 0.18 kJ mol −1 and 98.68 ± 0.49 J K −1 mol −1 respectively from the experimental C p– T curve. The thermodynamic functions [ H T 0 − H 298.15 0 ] and [ S T 0 − S 298.15 0 ], were derived from the heat capacity data with an interval of 5 K. The standard molar enthalpy of combustion and formation of the compound have been determined to be Δ c H m 0 ( C 5 H 12 O 5 , cr ) = ( − 2562.4 ± 1.3 ) kJ mo l − 1 and Δ f H m 0 ( C 5 H 12 O 5 , cr ) = ( − 1120.1 ± 1.5 ) kJ mo l − 1 respectively by means of a precision oxygen-bomb combustion calorimeter at T = 298.15 K. The thermostability of the compound was further studied by DSC and TGA measurements.