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Things You'll Need
Instructions
Take a moment to put on your gloves, goggles and lab coat. Make sure the fume hood is on and operational. Perform the whole experiment under the fume hood so that flammable vapors do not accumulate.
Wrap the fractionating column in glass wool to provide insulation, then wrap it in aluminum foil to hold the wool in place.
Take your round-bottomed distillation flask and place it in a cool heating mantle. Secure it with a clamp to one of the ring stands.
Pour 50 mL of the liquid you want to separate into the distillation flask and add a few boiling stones.
Connect the fractionating column to the top of the distilling flask, and connect the other end of the fractionating column to the distilling head. Connect the distilling head to the thermometer adapter with the thermometer inserted into it. The distilling head is T-shaped, so together with the thermometer and the fractionating column, it should now form the uppermost part of a long vertical column with the thermometer on top. Make sure the tip of the thermometer is below the sidearm of the distilling head; this will ensure the thermometer is bathed in vapor so it gives an accurate temperature reading.
Connect the other opening in the distilling head to the condenser, and use a Keck clip to hold them together. Secure the condenser to the second ring stand with another clamp to make sure it stays horizontal.
Connect the other end of the water-cooled condenser to the vacuum adapter, and hold them together with another Keck clip.
Insert the other end of the vacuum adapter into the receiving flask, and hold the two together with another Keck clip. Secure the receiving flask with a clamp. Note that the vacuum adapter now has a port open to the air; this will prevent pressure from building up in the system. Do not block the open vacuum adapter port.
Connect one of the two hoses to the two ports on the condenser. Next connect the hose farthest from the distilling head to a water outlet or tap and the hose closest to the distilling head to a sink or drain. Turn on the tap to provide a slow, gentle water flow. This setup will cool the vapor and causes it to condense.
Wrap the top of the distilling flask in glass wool to provide some more insulation. You may want to use aluminum foil to hold the wool in place.
Turn on the heating mantle and bring the solution in the distillation flask to a gentle boil. The rate at which liquid enters the receiving flask should be between one drop per second and one drop every two or three seconds. This rate will offer a good compromise between separation and speed. Remember that you don't need very high heat to boil most of the mixtures you'll work with. Hexane, for example, boils at a mere 69 degrees Celsius.
Watch the temperature at the distilling head and periodically collect fractions by transferring the contents of the receiving flask to a vial. It's a good idea to have two or more receiving flasks so you can simply exchange the one for the other when you do so.
Collect the first fraction when the temperature at the distilling head reaches the boiling point of the more volatile component. The temperature will hover around that point for a while then start to fall. Increase the heat at this point and when the temperature reaches the boiling point of the less volatile component, collect a second fraction. Collect the third fraction and stop the distillation when only a few mL of the mixture remain in the distillation flask.
Label your vials, disassemble your apparatus and make sure you clean your workspace adequately.