Distillation Techniques Full PDF

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Experiment 4: Distillation Techniques

Esther Kadoch 1934019

Presented to Roger Machaalani

Dawson College 202-BZF-05 00002

March 3rd, 2021 March 10th, 2021

Objective: This experiment's objective is to determine acetone-water's boiling point using the simple and fractional distillation of a binary liquid mixture.

Introduction: Distillation is a process in which separates two mixtures with two different boiling points to purify liquid substances. This process involves phase changes from liquid to gas to liquid, again. The impurities are left behind as it takes place. There are two different techniques in distillation a binary liquid mixture: simple distillation and fractional distillation.

The first technique is described as boiling the liquid, then cooling down the vapours, so they condense back to liquid form. In distilling pure liquids, the substance with the lowest boiling point will evaporate first, with a constant temperature until all is gone; then will the second substance will evaporate. However, the distillation of a binary mixture of two liquids engages in a vapour mixture of both substances, giving inconstant temperature data.

The second technique is the same as simple distillation but with the addition of a fractional distillation column, packed with glass beads, to the setup. The column allows the liquid with the lowest boiling point to fight its way up the column while changing phases continually. As the vapour-liquid rises the column, it becomes more volatile. Like the simple distillation, the best-case scenario would be that the lower-boiling liquid would be almost

completely separated and collected from the second liquid, giving a constant reading of the temperature until the second liquid starts to evaporate.

This experiment requires simple mathematical formula, such as finding the percentage by volume. It can be represented as: Percentage by volume = | volume before the raise in temperature ÷ total volume | × 100 %

Data and Results: Literature value of the boiling point of acetone: 56 ºC Part 1: Simple Distillation of a Binary Liquid Mixture Volume (mL)

Temperature (ºC)

1st drop

61.0

2.0

63.0

3.0

64.0

6.0

66.0

8.0

69.0

10.0

74.0

12.0

87.0

13.0

99.0

14.0

101.0

15.0

102.0

Part 2: Fractional Distillation of a Binary Liquid Mixture Volume (mL)

Temperature (ºC)

1st drop

56.0

2.0

57.0

3.0

57.0

6.0

58.0

8.0

58.0

10.0

58.0

12.0

58.0

13.0

58.0

14.0

100.0

15.0

100.0

Graphs:

Sample Calculations: ** No sample calculations for this laboratory

Conclusion: In conclusion, the most accurate type of distillation is fractional distillation, with an average for the acetone boiling point of 57.5 ºC compared to 64.6 ºC for simple distillation since the literature value of acetone is 56 ºC. An error that may have occurred during this lab might have been that the distillation was too fast. A distillation lab requires time to let the two liquids separate correctly. If the collected liquid in the graduated cylinder fills up too fast, the distillation was done right. A solution to this problem can be to lower the heat of the heating mantle. This experiment was successful because acetone's boiling point found with the fractional distillation of a binary liquid mixture is 57.5ºC and is very close to its literature value of 56 ºC.

Post-Lab Questions: 1. The average of temperature where the slope of Graph 1 is approximately zero is from the first drop to 8.0 mL. Average = (61.0 + 63.0 + 64.0 + 66.0 + 69.0) °C ÷ 5 = 64.6 °C The average of temperature where the slope of Graph 2 is approximately zero is from the first drop to 13.0 mL. Average = (56.0 + 57.0 + 57.0 + 58.0 + 58.0 + 58.0 + 58.0 + 58.0) °C ÷ 8 = 57.5 °C

2. Percentage by volume = | volume before the raise in temperature ÷ total volume | × 100 % Percentage by volume = |13.0 ÷ 30.0|mL × 100 % = 43.3 %

3. Looking at the Fractional Distillation Graph (Graph 2), we can see that the average of the temperature is closer to the literature value compared to the second graph temperature average. The data is more accurate using the fractional distillation than simple distillation because this process is better at separating mixed liquids with smaller boiling points, like acetone and water....