Fractional distillation is the separation of a mixture into its fractional parts that entails many concurrent vaporization-condensation cycles. This works because of different boiling points of individual substances. The temperature of the fractional distillation column decreases as its length increases. A higher boiling point component condenses on the column and returns to the solution whereas the lower boiling point component passes through the column and is collected in a receiver and its purity increases.
II. Experimental Procedure
1. Assemble apparatus for fractional distillation using a 50 mL round bottom flask for the boiling flask and three 10 mL graduated cylinders for the receiver.
2. Add 20 mL of 50:50 mixture of ethyl acetate (EtOAc) and butyl acetate (BuOAc), the distilland and boiling chips to the boiling flask.
3. Pack the distilling column with a copper sponge and wrap the column with aluminum foil.
4. Turn on cooling water and heat source.
5. Record the temperature after distillation begins.
6. Set the variac to eight for the first fractional sample. Collect the sample from the time the mixture begins heating till the temperature reaches 85◦C.
7. Set the variac to high and collect the sample until the temperature reaches 110◦C.
8. With the variac still set to high collect the third sample until the boiling flask is almost dry.
9. Remove the heat source and drain the distilling column.
10. Measure the volume of each fraction received and record the results.
11. Determine the percent pure for each component of the mixture.
12. Pour some of each fraction into three separate vials, label and store.
13. Disassemble and clean the fractional distilling apparatus using hexane for the joints and acetone for the glassware.
(boiling point ~ 78◦C)
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