From evaporative to cooling crystallisation

Kate Wittering, Josh King, Lynne H. Thomas, Chick C. Wilson

OAI: oai:purehost.bath.ac.uk:openaire_cris_publications/ae229192-2a4a-4070-a9b6-4ff5db32d8ae • DOI: https://doi.org/10.3390/cryst4020123

Two new multi-component molecular complexes of cytosine and 5-fluorocytosine with 4-chloro-3,5-dinitrobenzoic acid are presented. Materials synthesis was achieved initially by evaporative crystallisation and the crystal structures determined. The process was then successfully transferred into a controlled small scale cooling crystallisation environment, with bulk samples shown to be representative of the multi-component product phase, by powder X-ray diffraction (PXRD) and differential scanning calorimetry (DSC) methods. Turbidity measurements are shown to be a valuable process analytical technology probe for characterising the initial stages of molecular complex formation in solution. The significance of these findings for scale-up of crystallisation of multi-component molecular materials and for future transfer into continuous cooling crystallisation is discussed.