Procedure
• As described in the lab manual (CHM 1321 Organic Chemistry Laboratory Manual, Dr. Tony Durst et. al., Sept. 2013, Exp.2, pg. 20-27.)
• Replace the receiving flask with a graduated cylinder for better measurement of the distillate.
• Replace thermometer with a temperature probe for more accurate temperature readings.
• Use aluminum foil to insulate the fractionating column.
Observation
• The process of warming the liquid was slow and tedious. The warming took an average of 30 minutes.
• When there was about 2-5 mL of mixture left in the flask, the vapour was no longer able to make it to the condenser and it would fall back into the flask. The distillations were stopped after this point as minimal liquid was being collected in the
…show more content…
This is due to the boiling points of the two compounds are too close for an effective simple distillation. A simple distillation only works when the boiling points of the two compounds are separated by at least 50 °C (CITATION). Meanwhile, the boiling points of the compounds of the mixtures are 82.3 °C for 2-pronanol and 117 °C for 1-butanol (National Center for Biotechnology Information).
As well, while fractional distillation is more difficult due to the added fractionating column and insulation, it allows for better separation and condensation of the individual compounds. This ensures that only the compound with the lower boiling point is completely condensed before the compound with the higher boiling point begins to condense.
Therefore, this means that the 2-propanol has condensed completely before 1-butanol had begun to, allowing the individual boiling points to be clearly analysed. As well the product can be pure 2-propanol if the temperature is decreased before the 1-butanol begins to condense. Compared to the simple distillation, it would be difficult to identify when the two compounds would be separated from the ever-increasing temperature. In addition, if one was intending to separate compounds with close boiling points, fractional distillation would better the better distillation