Thermodynamic properties of myo-inositol

Abstract

In the present work, the temperature dependence of heat capacity of vitamin B8 (myo-inositol) has been measured for the first time over the range from 8K to 340K by precision adiabatic vacuum calorimetry. Based on the experimental data, the thermodynamic functions of the vitamin B8, namely, the heat capacity, enthalpy H°(T)–H°(0), entropy S°(T)–S°(0) and Gibbs function G°(T)–H°(0) have been determined for the range from T→0K to 340K. The value of the fractal dimension D in the function of multifractal generalization of Debye’s theory of the heat capacity of solids was estimated and the character of heterodynamics of structure was detected. The enthalpy of combustion (−2747.0±2.1)kJ·mol−1 of the vitamin B8 was measured for the first time using high-precision combustion calorimeter. The standard molar enthalpy of formation in the crystalline state (−1329.3±2.3)kJ·mol−1 of B8 at 298.15K was derived from the combustion experiments. Using combination of the adiabatic and combustion calorimetry results the thermodynamic functions of formation of the myo-inositol at T=298.15K and p=0.1MPa have been calculated. The low-temperature X-ray diffraction was used for the determination of coefficients of thermal expansion.