Fractional Distillation Organic Lab Report
Organic Lab 1: Fractional Distillation
Discussion:
With the purpose of the experiment being to identify the 30 mL of unknown liquid, the theoretical basis of simple and fractional distillation must be deconstructed and applied to the data obtained describing the liquid in question.
Simple distillation is a separation technique which can be used to separate and purify distillates from a liquid mixture which ideally contains one volatile and one non-volatile compound. If such ideal conditions are not possible—as is usually the case—then simple distillation can be applied as long as the liquid in question is composed of compounds that differ in volatility such that their boiling points differ by at least 40 to 50 degrees Celsius. Because the very essence of simple distillation is relies upon the idea that more volatile compounds have lower boiling points and thus when heated to this boiling point will occupy most if not all of the vapor above the liquid pot residue. Because the difference in boiling point for the compounds in a mixed liquid must at least differ by 40 to 50 degrees Celsius in order for purification through Simple Distillation, this procedure should not result in a high amount of impurities in the distillate or pot residue since the difference between both boiling points is great enough that most of the lower boiling point liquid should vaporize without vaporization of the higher boiling point liquid. The experimental set up for the simple distillation procedure is the standard procedure which invokes the use of a a heat source, a magnetic stirrer, a receiving flask for the distillate to be collected in, a condenser with an accompanying inflow of cold water, a stillhead, a thermometer, a rubber adapter, an adapter, and keck clips. The keck clips are used to stabilize the glass joints while the condenser cools the vaporized gas to liquid. Because the stillhead is where the vapor collects, and the thermometer attached to the top of the stillhead must
Discussion:
With the purpose of the experiment being to identify the 30 mL of unknown liquid, the theoretical basis of simple and fractional distillation must be deconstructed and applied to the data obtained describing the liquid in question.
Simple distillation is a separation technique which can be used to separate and purify distillates from a liquid mixture which ideally contains one volatile and one non-volatile compound. If such ideal conditions are not possible—as is usually the case—then simple distillation can be applied as long as the liquid in question is composed of compounds that differ in volatility such that their boiling points differ by at least 40 to 50 degrees Celsius. Because the very essence of simple distillation is relies upon the idea that more volatile compounds have lower boiling points and thus when heated to this boiling point will occupy most if not all of the vapor above the liquid pot residue. Because the difference in boiling point for the compounds in a mixed liquid must at least differ by 40 to 50 degrees Celsius in order for purification through Simple Distillation, this procedure should not result in a high amount of impurities in the distillate or pot residue since the difference between both boiling points is great enough that most of the lower boiling point liquid should vaporize without vaporization of the higher boiling point liquid. The experimental set up for the simple distillation procedure is the standard procedure which invokes the use of a a heat source, a magnetic stirrer, a receiving flask for the distillate to be collected in, a condenser with an accompanying inflow of cold water, a stillhead, a thermometer, a rubber adapter, an adapter, and keck clips. The keck clips are used to stabilize the glass joints while the condenser cools the vaporized gas to liquid. Because the stillhead is where the vapor collects, and the thermometer attached to the top of the stillhead must
References: Experimental Organic Chemistry: A Miniscale and Microscale Approach, 5th ed. By Gilbert and Martin, Section(s)2.13- 2.14, 4.3-4.4. Investigating gas chromatography. (2013). Retrieved from http://www.vernier.com/experiments/chem-o/8/investigating_gas_chromatography/ Figure 8: Pre Fractional Distillation GC Results Sample | Boiling range (°C) | Volume (mL) | % Composition (lower bp : higher bp) | Fraction A | 52-54 | 14 | 60.66:33.15 | Fraction B | 35-84 | 6 | NA | Fraction C | 84-89 | 7 | 57.15:42.84 | Mixture | NA | 30 | 30.2/69.8 | Table 2: Tabulated Values