Our group focuses on crystal engineering and crystallization process development. By understanding and modifying solid state properties we also aim at developing novel crystallization applications. We strive to understand crystallization processes that are still at early stage of development (R&D, gram to kilogram scale), as well as processes that are being brought up to industrial scale (from early-scale up, through pilot-plant, and up to production scale).
In crystal engineering, one aims at fine-tuning the properties of the solid state, by using knowledge on intermolecular interactions responsible for a given crystal lattice.
We work in this field on thermo- , photochromic and solvatochromic compounds , which are materials that change color upon heating, irradiation or solvatation. By alterning the nature of the solid state we aim at impacting these properties.
Crystallization process development
Crystallizations are often the final step in the production of organic or inorganic compounds. This step is therefore directly determinant for the final outcome (yield, purity, etc.). Although these processes seem quite straightforward, problems such as caking, yield loss, unexpected polymorphism, un-controlled particle size distribution,... frequently occur, even on industrial scale. These problems can most of the time be avoided by a more profound understanding of the crystallization process. During process development, often less than 10% of the total effort is dedicated to crystallization development, which seems contradictory to the evident importance of this step. A small overview of recent litterature will show the interested reader that crystallization is still `poorly` understood from a fundamental point of view. However some common rules should always be followed when developping a crystallization process.
- Study the solid state of the compound (polymorphism, solvatism, racemic/conglomerate compound, solid liquid phase diagrams, ....)
- Introduce a solvent into the picture (solvent screening, solubility diagrams, ternary phase diagrams, ...)
- Study process parameters at a lower scale (stirrer type and rate, reactor design, seeding, particle size, ...)
- Scale-up the process
Although interested in all four areas, our current focus lies in the development of alternative solid forms and the use hereof to stabilize the system (control of solid state), to develop new applications, or even to use as alternative new formulation form of pharmaceutical compounds. We are currently active in the field of resolution, purification, separation through formation of multi-component crystals. We also investigate controlling the properties of the final solid form to avoid process issues (eg. hygroscopicity, stability, ...)