Classroom experiments with artificial sweeteners: growing single crystals and simple calorimetry

Abstract

An easily accessible experimental set-up to grow large single crystals of two sweeteners readily available in supermarkets, erythritol and xylitol, is described. The crystallization of these compounds illustrates the principles of crystallization by evaporation. As these artificial sweeteners are also known to induce a cool sensation in the mouth, the crystal-growing experiment is complemented with a simple calorimetric set-up to demonstrate the endothermic nature of the dissolution of the selected sweeteners in a more quantitative approach by measuring the heat of dissolution (Delta H-diss). The choice of these two sweeteners also allows use of the freely available WebCSD and Mercury tools to visualize their three-dimensional structure, crystal packing and powder diffractograms, and to deepen stereochemical concepts such as stereoisomers and meso compounds.