Reactions can be conducted without solvents and the concept of ‘solvent-less chemistry’ has been around for many years. This provides one of the simplest solutions to problematic solvents. Although some large-scale commodity chemicals are manufactured without the use of solvents, the chemistry of solvent-less reactions becomes more complicated, limiting the usefulness of this approach.
Performing large-scale, exothermic reactions in the absence of a solvent, which otherwise would act as a heat sink, should be approached with caution from a safety perspective.[1] Efficient mixing in the absence of solvents can also be problematic, especially when using solid reagents.
Even in solvent-less reactions, solvents are still often required for extraction, separation and purification of products.