In solvent screening and process optimisation, parallel systems with small process batches can deliver fast and good results for later process control in crystallisation.
In chemical reactions, solvents are used, for example, to enable two solids to react more easily without the solvent being involved in the reaction. Solvents are therefore important components in chemistry, and are missing in almost every chemistry laboratory.
In an anti-solvent, on the other hand, a compound is less soluble. Usually, a solvent/anti-solvent mixture is used to obtain crystals, especially for organic compounds.
Solubility determination and concentration determination are an important part of the daily work in some laboratories. Anyone who deals with this inevitably encounters functional relationships between concentrations and temperature as a variable.
SOLUBILITY DETERMINATION
When determining solubility, the focus is on finding suitable solvents and anti-solvents at an early stage of the test. With the help of this information, reaction and process parameters can be designed in such a way that the most economical result can be achieved with the best solvent system and the appropriate temperature control.
CRYSTALLISATION
In a crystallisation, crystals are to be grown in a controlled manner, for example from a solution, ie crystals with desired properties such as certain physical and chemical properties as well as size and appearance. Initial condition is a supersaturated solution. The crystallisation can be controlled, for example, by a defined cooling and temperature control via a temperature control unit, and thus supersaturation can be maintained. The range between solubility and turbidity of the solution. The desired process parameters can be maintained by changing the temperature (cooling).
As with the determination of solubility, it also makes sense here to find the conditions in advance on a smaller scale and with different concentrations, which will subsequently ensure economical working, for example on a production scale. Here, too, several samples can be analysed simultaneously with a parallel system such as the Xelsius-STS system.
In the end, the findings can flow back into the scale-up operation. Due to the possibility of operating several samples at different temperatures, the conditions that deliver a higher success and yield can be found quickly.
