Solvent Selection

Researcher: Andrew Lang

For certain reactions, where product precipitation at room temperature is the goal, an optimal solvent should have as many of the following properties as possible, see ONSCpaper01 for more details:
  1. All the reactants and intermediates should be able to form solutions with concentrations high enough (e.g. 0.3M) to run a good synthesis attempt.
  2. The solubility of the product should be ideally as low as possible to maximize yield (e.g. 0.03M).
  3. The boiling point of the solvent should be low enough to allow for easy evaporation at room temperature (e.g. methanol 48.1C).

Using a model that can predict the solubility of compounds in 70+ solvents, we have released a web service than ranks solvents based upon a score that reflects the three solvent criteria above and represents the theoretical percent yield after n washes (default n = 0) for reactions run at either 1M or the concentration of the limiting reactant, whichever is lower :
score = (min(reactants solubility, 1) - (1 + washes) * product solubility) / min(reactants solubility, 1) * 100
The webservice displays results sorted first by the number of criteria met (limiting reactant solubility - default 0.3M, product solubility - default 0.03M, bp of solvent - default 100C) and then by the theoretical percent yield. The default criteria values may be manipulated via the form or directly in the url to better explore the solvent space

The results are also colour-coded according to the following key:
  • All three criteria met.
  • Two criteria met.
  • One criterion met.
  • No criteria met.

The webservice requires the user to pass ChemSpider IDs for each reactant and the product (at the end) in a url. The following is an example of its usage taken from our collection of reaction attempts (where this service has been integrated):
http://showme.physics.drexel.edu/onsc/models/solventselector.php?csids=7135|80987|9906289