To address this, heating under re-flux is used. This refers to heating a solution with an attached condenser to prevent reagents from escaping. When dealing with organic reactions, heating under re-flux is often required, such as the oxidation of Toluene using acidified KMnO4 and dilute H2SO4 to Benzoic acid(C6H6O2). purpose is allows for liquid to boil and condense, with the condensed liquid returning to the original flask. A re-flux setup is analogous to a distillation, with the main difference being the vertical placement of the condenser. The liquid remains at the boiling point of the solvent (or solution) during active re-flux.
