Heat capacity and enthalpy of indapamide

Publication date: Available online 30 January 2019Source: Thermochimica ActaAuthor(s): M. Skotnicki, A. Drogoń, J.J Calvin, P.F Rosen, B.F Woodfield, M PydaAbstractThe heat capacities and total enthalpy of anhydrous indapamide (IND, CAS no.: 26807-65-8) are reported from temperature 1.84 to 523.15 K measured by a Quantum Design Physical Property Measurement System® (PPMS) and differential scanning calorimetry (DSC). The low-temperature experimental heat capacities of crystalline IND from 1.84 to 302.65 K were measured by PPMS and fit to a theoretical model in the low temperature range (T < 7.68 K), orthogonal polynomials in the middle temperature range (7.68 < T < 54.15 K), and a combination of Debye and Einstein functions in the high temperature range (T > 54.15 K). The calculated heat capacities were extended to a higher temperature to be used as a reference line of solid heat capacity, cp(solid). The experimental heat capacity of liquid, cp(liquid) for amorphous indapamide above the glass transition (Tg(midpoint on cooling) = 369.7 ± 0.6 K) was approximated by linear regression and was expressed as cp(liquid) = (0.954 + 0.0023T) J·K–1 g–1. The solid and liquid heat capacities of IND were applied as reference lines for advanced thermal analysis of the experimental, apparent heat capacity data measured by DSC. The change in heat capacity (Δcp) of 0.45 J·K–1 g–1 at Tg for fully amorphous IND and heat of fusio...

Source: Thermochimica Acta - January 30, 2019 Category: Chemistry Source Type: research