CHEMISTRY 321 LABORATORY
Distillation Experiment
General Note
• Be certain to check the atmospheric pressure on the day you complete this experiment. The
instructor will demonstrate the use of the temperature-pressure nomograph for correcting
the boiling points according to the atmospheric pressure.
Simple Distillation
A. Macro Scale
Arrange an apparatus for distillation like that illustrated in Figure 8.11, p 629 in your text,
using a 25 or 50 mL graduated cylinder as the receiver. Be sure to apply a thin film of stopcock
grease to each male joint in the ground-glass connections. Your instructor will demonstrate the
correct assembly of the apparatus. Before beginning the distillation, have your set-up checked by
the instructor or the lab assistant.
Pour 25 mL of 2-propanol into a 50 mL distilling flask using a long-stem funnel. Add a
boiling chip to the flask, replace the thermometer, start the water circulating gently through the
condenser, and check all glass-to-glass connections to make sure they are tight. Turn on the
Minitrol to begin heating. When the liquid starts to boil, adjust the voltage so that the liquid distills
at a rate of about one drop every two seconds. Record the temperature of the vapor when the first
drop of distillate falls into the receiver and at the end of each 1 mL of distillate. Collect a total of
about 12 mLs of distillate. The beginning and ending temperatures you recorded constitute the
observed boiling point range. Save the distillate for the next experiment. Discard the residue (in
the distilling flask) down the sink, with running water.
Clean the apparatus by rinsing it with water, then allow it to dry while you do the micro
scale distillation. You’ll use the same pieces of glassware (plus one more) for the macro scale
fractional distillation.
B. Micro Scale
Arrange a distilling apparatus as shown in Figure 8.5, p. 622 in your text, with the addition
of a collar of aluminum foil (shiny side down) between the Hickman head and the conical vial and
the deletion of the drying tube (right angle tube attached to water-jacketed condenser). You’ll be
using a sand bath instead of an aluminum block. Support the thermometer by placing it between
the arms of the clamp attached to the Hickman head. Adjust the voltage on the hot plate so that the
sand bath temperature is about 130-140oC. Place 3 mL of 2-propanol into a 5 mL conical vial, add
the larger spin vane, and connect the vial to the Hickman head. Start the water flowing slowly
through the condenser, then lower the distillation setup so that the vial is submerged in the sand
bath to a depth of 2 cm. If necessary, you may adjust the voltage on the hot plate either up or down
to attain an appropriate distillation rate. Turn on the magnetic stirrer to prevent bumping.
Alternatively, you may add a boiling chip instead of using the magnetic stir vane. Continue the
distillation until there is a noticeable amount of distillate in the well of the Hickman head.
