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. Whilst some large scale commodity chemicals are manufactured without the use of solvents, as the chemistry becomes more complicated, the use of solvents is normally required.
The use of solvents is particularly important in for example exothermic reactions, particularly on a larger scale where the solvent can act as a heat sink. 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.