Separating Liquids by Distillation

Learn that distillation separates miscible liquids based on differences in boiling points. Heat the mixture to a temperature above the boiling point of one compound but below the other, causing the lower-boiling component to vaporize while the higher-boiling component remains liquid.

Set up a round-bottomed distilling flask above a heat source with boiling chips added to the mixture. Connect a thermometer positioned at the side arm to measure vapor temperature, attach a condenser with separate inlet and outlet for cold water circulation, and position a receiving flask to collect the distillate.

Fill the distillation flask no more than half full to prevent contamination of the distillate. Verify that the thermometer is positioned correctly at the vapor entry point and ensure the heat source can be quickly removed if needed.

Clamp every piece of glassware properly, especially the condenser, using clips to connect all components securely. This prevents equipment shifts and ensures safe operation during the distillation process.

Bring the mixture to a gentle boil, causing vapor to rise into the condenser where cold water circulation condenses it back into liquid. Collect the distillate in the receiving flask, preferably only within the temperature range corresponding to the desired compound's boiling point to minimize contamination.

Understand that fractional distillation with a fractionating column separates mixtures with many components, such as industrial applications. Recognize that azeotropic mixtures like ethanol-water require special techniques because their vapor composition matches the liquid composition.