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Home , Distillation

DISTILLATION AND

R EADING Zubrick, Ch. 4, 17, 18, 19 (“Simple”/“Fractional” Distillations), 30, and 34 Instrument handout Using the Gas Chromatograph-Flame Ionization Detector (GC-FID)

PROCEDURE

Make 20 mL of a 1:1 solution of acetone and 1-propanol and distill (with chip) in an appropriately- sized round-bottom flask (see Zubrick). Distill using the method you have been assigned, collecting the distillate in a 10 mL graduated cylinder. Have your instructor check your setup before starting.

As you distill, record the temperature and the total volume of distillate collected for every milliliter you collect. After 4 mL of distillate has been collected, quickly pour it into a vial labeled cut 1 and cover. Replace the cylinder.

Repeat this with 4 mL fractions labeled cut 2, cut 3, and cut 4. Cut 5 will be the solution remaining in the distillation apparatus once it is allowed to cool.

Obtain the GC traces for all five cuts, using each trace to determine the mass percent and retention time of each component (see handout on using the software). To save time, one member of each group may be able to run the GC traces as you collect cuts, while another member stays with the distillation. Ask your instructor.

From your data, you will make the two graphs below. If you did not perform both types of distillation you will have to partner (or your instructor will partner you) with a group that did.

• Temperature (y-axis) versus total volume collected (x-axis) for both simple and fractional distillations. • Percent acetone versus cut #, for both distillations. Repeat for propanol and include on the same axes if you can (your instructor can help you use Excel).

In your notebook, you should have neat tables of your temperature/volume data and % composition/cut # data for both types of distillations. All graphs and GC traces should be pasted appropriately in your notebook (with titles and labels). Calculations of peak areas should be shown directly on the traces.

Discuss the differences between the simple and fractional distillations, as evidenced by your data and the graphs. Specifically address each of your graphs and how they are different for the two types of distillations.

Organic Lab Manual Harper College, Fall 2010