Phenomenology of polymorphism and topological pressure-temperature diagrams: the case study acesulfame

I.B. Rietveld^1*, R. Céolin¹, S.P. Velaga² and S. Basavoju²

¹ Laboratoire de Chimie Physique, EAD Physico-Chimie Industrielle du Médicament, Faculté de Pharmacie de l’Université Paris Descartes, 75006 Paris, France
² Department of Health Sciences, Luleå University of Technology, Luleå S-97187, Sweden

^* ivo.rietveld@parisdescartes.fr

Abstract

The phase relationships involving the two known polymorphs of acesulfame have been determined from experimental data through topological arguments based on the Clapeyron equation. It is found that the resulting topological P-T diagram, in which the behavior of acesulfame form II becomes monotropic at higher pressure, resembles that the “paradigmatic” S₈ dimorphism.