Foundation: Solvents

Solvent selection

Frequently a solvent is chosen for a particular reaction due to literature precedent or in-house routine practice.  However a more strategic approach should take into consideration the following:

  • Inert under reaction conditions
  • Chemistry must work!
  • Isolation/work-up/crystallisation
  • Safety and operability
  • Human health issues
  • Can the solvent be recovered/recycled?
  • Can wastes be incinerated/treated?
  • Environment and legislation compliance
  • Overall cost burden to final product

Substitutes can also be sought from solvent selection guides (see Solvent Selection Guides in the Guides and Metrics topic.)  A number of solvent selection guides have been published with the purpose of promoting the uptake of more sustainable solvents.  These guides give the user a quick method of identifying problematic solvents and subsequently recommending preferred alternatives.

Design of Experiments (DoE) and Principal Component Analysis  (PCA) can be used as tools to identify solvents to screen, and assist in decision making when looking for replacement solvents.[1]

Other alternative solvents (and solvent-less reactions) are explored in more detail in the solvents topic including water, bio-derived solvents, supercritical fluids and ionic liquids.

  1. J. D. Moseley and P. M. Murray, Ligand and solvent selection in challenging catalytic reactions, J. Chem. Technol. Biotechnol., 2014, 89, 623-632.