Standard Molar Enthalpy of Sublimation of Form I Nicotinamide

I.O. Feliciano, C.E.S. Bernardes, M.E. Minas da Piedade

J. Chem. Thermodyn. 2023, 182, 107042.

DOI: 10.1016/j.jct.2023.107042.

Abstract

The standard (p^o = 0.1 MPa) molar enthalpy of sublimation of form I nicotinamide (NIC, cr I), at 298.15 K, was determined by drop-sublimation Calvet microcalorimetry. Experiments carried out under isothermal and nonisothermal conditions led to Δ_subH_m^o(NIC, cr I) = 108.0 ± 0.5 kJ mol^-1. The present study allowed to resolve to a significant extent the large discrepancy observed between published Δ_subH_m^o(NIC) results obtained by calorimetry and by vapor-pressure measurements, using samples of unspecified crystal form.

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