 The name "Schotten–Baumann reaction conditions" is often used to indicate the use of a two-phase solvent system, consisting of water and an organic solvent.The base within the water phase neutralizes the acid, generated in the reaction, while the starting materials and product remain in the organic phase, often dichloromethane or diethyl ether.The presence of a base prevents the amine reactant from being protonated, which would make it unable to react as a nucleophile.