There are a few common ways to avoid the use of solvents when running a chemical reaction. The simplest situation is when one of the reagents can serve as the solvent for the reaction. This is commonly referred to as running a reaction “neat” (yes, like scotch). Reagents that are not liquids at ambient temperatures can also be used in the molten state so that they can be used as solvents. Some reactions can also be run on solid-supported catalysts that do not require a solvent. By avoiding the use of solvents, each of these approaches cuts down on costs and on the amount of waste generated.