7.4: Reflux

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Table 7.4: Procedural summary for reflux.

Pour liquid into the flask along with a stir bar or boiling stones. Use an extension clamp on the round bottomed flask to connect to the ring stand or latticework. Attach the condenser, and connect the hoses so that water travels against gravity (cooling water comes into the bottom and drains out the top). Be sure there is a secure connection between the round bottomed flask and condenser, as vapors escaping this joint have the potential to catch on fire.	Circulate water through the condenser, then begin heating the flask (by using a heating mantle, sand, water, or oil bath). Use an adjustable platform so the heat can be lowered and removed at the end of the reflux, or if something unexpected occurs.	Heat so that the "reflux ring" is seen in the lower third of the condenser. Turn down the heat if the refluxing vapors reach higher than halfway up the condenser.	At the end of the reflux period, lower the heat source from the flask or raise the apparatus. Keep circulating water in the condenser until the flask is just warm to the touch. After air cooling somewhat, the flask can be quickly cooled by immersing in a container of tap water.