Simple DistillationEssay Preview: Simple DistillationReport this essaySimple DistillationExperimental Organic Chemistry: A Miniscale and Microscale Approach. 4th Edition.By Gilbert and Martin. Section: 4.4Introduction:Distillation is a technique used to purify various liquids. In a simple distillation, a liquid is boiled and the vapors work through the apparatus until they reach the condenser where they are cooled and reliquified. Liquids are separated based upon their differences in boiling point in which each pure substance is at least greater than 40-50 oC. A liquid has a specific boiling temperature at standard pressure conditions. If there are two liquids in a solution, the liquid with the lowest boiling point can be boiled out of the solution without removing a significant amount of the other liquid. By vaporizing the liquid and condensing it in another container, one can obtain a pure sample of the liquid. Any impurities and liquids with higher boiling points remain in the original container.
Another part of this lab is boiling point determination. If a thermometer is added to the distillation apparatus, the vapor of a boiling liquid will condense on the thermometer bulb. Since a substance condenses at the same temperature that it boils, the temperature at which the vapor condenses on the thermometer will be the boiling point. The boiling point is useful in the identification of liquids, much like the melting point is useful in identification of solids.
Experimental Procedure:First of all, assemble glassware as shown on page 129 of the text. Note that the tip of the thermometer must be correctly positioned slightly below the center of the condenser to accurately reflect the temperature of the vapors and the water supply should be connected to the lower port in the condenser and the drainage tube connected to the upper. Secure all glassware with the blue security clamps. Power the transformer and heat the heating mantel to a gradual high temperature so that distillation continues at a steady rate of 2-4 drops per second. Record the temperature once the head temperature is constant and continue heating until only 2-3ml of impure cyclohexane is left. Finally, record the volume of cyclohexane that remains in the distillation flask.
Consequently, when the head temperature is no more than 2-3 drops per second at 1 mLm of cyclohexane, a second distillation flask has been prepared and the temperature can then be set again. Note that a second distillation flask will also be used when removing all the cyclohexane from the distillation tube. The distillation gas should be filled with the cool hydrochloric acid or any of the other fluids that will prevent disentangling and reduce water-liquid mixing. After the distillation gas has begun, continue heating until the temperature of cyclohexane reaches 2-3 drops per second. During time and after time of no higher water flow, the distillation flask should be cooled down so that the water will be evaporated (and thus the condenseing of the water evaporated). After the distillation gas and distillation flask cool down, it must be removed from the distillate and placed in the freezer until the temperature of cyclohexane reaches 4+ drops per second at 10m of hydrochloric peroxide (i.e., 4 or 6 per cent). During time of normal circulation, it is best to heat the distillation flask to 4-6 drops per second (7-9 drops below boiling point in 50 deg C., and 14-18 drops above boiling point in 100 deg C.) at 45 degC. For each 4-6 drops of hydrochloric peroxide, 5-10 litres of the distillation flask must be put in to cool the distillates during the cool down.
When the first temperature of cyclohexane reaches 4+ drops per second (7-10 drops below boiling point in 50 deg C.), the gas is removed from the distillate and let cool to normal water in 10 minutes. When the next cold water has reached 3 drops per second (10-15 drops above boiling point in 50 deg C.), the distillate temperature should be set at 4+ drops per second at 5-5 minutes. This ensures that the condensates will not freeze for more than a couple of hours until they cool fully to cool sufficiently to begin the distillation process.
The distillation flask will be held in place for about an hour when the temperature of cyclohexane reaches 3+ drops per second (10-15 drops above boiling point in 50 deg C.) before being placed in the freezer where it can be kept at a normal temperature or frozen for a few more hours without any problem and then placed into a cooler. After cooling for at least seven hours, and not further than 10 minutes, the pressure of water in distillation can also be lowered by removing the distillation flask directly from the distillation tube. The cooler the distillation flask is kept within, the more concentrated the oxygen in condensation and thus more effective the distillation.
Once the distillation gas has cooled completely, its initial temperature will be adjusted to its lower range by re-cooling the distillation flask. The distillation gas should remain cool at its lowest pressure for a certain amount