FRACTIONAL DISTILLATION
Purpose:
The purpose of this experiment is to use fractional distillation to separate a mixture of organic
liquids.
Discussion:
Answer the following questions:
1. What is the theory behind general distillation?
2. Why are boiling chips added to the mixture before heating?
3. Why are glass beads or copper turnings inserted into the vertical condenser?
4. What is the difference between simple and fractional distillation?
5. What are some of the major applications of fractional distillation?
Below is the general apparatus setup for a fractional distillation:
Thermometer
Ring
Stand
Thermometer
adapter
Three-way
Clamp
adapter
Narrow condenser
Vacuum adapter
Clamp
Clamps
Wide condenser
Ring
Round-bottom
Stand
flask
Heating mantle
Beaker
Wood block
Objectives:
In this lab, you will…
1. properly assemble a fractional distillation apparatus.
2. use fractional distillation to separate a mixture of organic liquids.
Safety:
Be extremely cautious as you assemble the apparatus. Get the apparatus approved by the
instructor before you begin the distillation. Wear safety goggles at all times after the apparatus has been
assembled.
Materials:
Organic glassware kit
Use the 100 mL round-bottom flask (RBF)
Glass beads or copper turnings
2 100 mL graduated cylinders
Heating mantle with temp control
Four red rubber tubes
Three beakers, less than 250 mL
Alcohol thermometer
Two ring stands
Four test tube clamps
Boiling chips (tamer tabs)
Cork round bottom flask holder
Boiling point apparatus
Chemicals:
Unknown organic mixture
Acetone (for cleaning)
Procedure:
1. Place the 100 mL round-bottom flask (rbf) in the cork rbf holder. Carefully pour the unknown
organic mixture into the 100 mL rbf. Add a couple boiling chips.
2. Use the diagram in the discussion to assemble the apparatus. Be sure to rinse the inside of each
piece of equipment used with a small amount of acetone. Place glass beads or copper turnings in
the vertical condenser.
3. Connect the bottom “in” stem of the condensers to the sink jet nozzles using a red rubber hose.
Connect a red rubber hose to the top “out” stem of the condensers and place the hose in the sink
so it can run into the sink drain.
4. Get your apparatus approved before moving to the next step.
5. Carefully turn on the cold water to both condensers.
6. Begin heating the mixture slowly by turning your heat to ~60%. After a few minutes, turn the
heat up to ~90%.
7. Observe the boiling process and watch for a “vapor ring” as it passes up the vertical condenser
into the 3-way adapter. Once the vapor hits the 3-way adapter and begins to condense in the
narrow condenser, it will begin to drip into your first graduated cylinder. Collect 5 mL of
distillate. Remove the graduated cylinder containing fraction 1, and immediately replace it with a
second graduated cylinder to collect fraction 2. Pour fraction 1 into a small test tube, label it, and
cork it.
8. Continue heating, and collect 10 mL of fraction 2. After that turn off the heat, and lower the
heating mantle. Fraction 2 will be put into the organic waste container – it most likely contains a
mixture of the two unknowns.
9. Fraction 3 will remain in the rbf. Once the apparatus cools to room temperature, pour fraction 3
into a small test tube, label it, and cork it.
10. Determine the boiling point of each fraction and record your results.
Cleanup:
 Carefully disassemble the apparatus. Rinse each piece of glassware with acetone inside and out
to clean it. Allow the components to dry, then place them back in the organic glassware kit.
 Return all equipment to its proper location.