Heat Capacity and Thermodynamic Functions of Crystalline β-Cytidine from 0 to 300 K

Abstract

The heat capacity of crystalline β-cytidine (C9H13N3O5; CAS Number: 65-46-3) was measured by adiabatic calorimetry in the range 12.99–299.38 K. The sample under study was defined in detail by X-ray phase analysis, infrared spectroscopy, differential thermal analysis (DTA)/thermogravimetric (TG) and elemental analysis. The melting point of cytidine has been determined. The analysis of the functional dependence of the heat capacity did not reveal any anomalies in its behavior associated with phase transitions. The experimental values of heat capacity were used to compute integral thermodynamic functions (entropy, enthalpy, and reduced Gibbs energy) in the range of 0 to 300 K. The standard entropy of crystalline β-cytidine formation was determined at T = 298.15 K.