Thermodynamics Research Center / ThermoML | Thermochimica Acta

ABSTRACT

In the present work temperature dependence of heat capacity of vitamin B2 (riboflavin) has been measured for the first time in the range from 6 to 322 K by precision adiabatic vacuum calorimetry. Based on the experimental data, the thermodynamic functions of the vitamin B2, 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 0 to 322 K. 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. In a calorimeter with a static bomb and an isothermal shield, the energy of combustion of the riboflavin has been measured at 298.15 K. The enthalpy of combustion centscH and the thermodynamic parameters centsfH , centsfS , centsfG and of reaction of formation of the riboflavin from simple substances at T = 298.15 K and p = 0.1 MPa have been calculated.