The purpose of the fractional distillation of alcohols lab was to learn a new technique to separate mixtures of our unknown compound into pure components using the specific vapor pressures of pure liquids. Before the fractional distillation lab was performed, a simple distillation lab was run. In the simple distillation setup, a boiling flask attached to an adapter holding a temperature probe. The adapter connected to a condenser into which water passed through. The condenser leads to a flask for the purified liquid. Fractional distillation was a better choice for this lab over simple distillation because
* Lighter fraction make better fuels as they ignite more easily and burn well, with cleaner (less smoky) flame.
14 mL of 9 M H2SO4 was added to the separatory funnel and the mixture was shaken. The layers were given a small amount of time to separate. The remaining n-butyl alcohol was extracted by the H2SO4 solution therefore, there was only one organic top layer. The lower aqueous layer was drained and discarded. 14 mL of H2O was added to the separatory funnel. A stopper was placed on the separatory funnel and it was shaken while being vented occasionally. The layers separated and the lower layer which contained the n-butyl bromide was drained into a smaller beaker. The aqueous layer was then discarded after ensuring that the correct layer had been saved by completing the "water drop test" (adding a drop of water to the drained liquid and if the water dissolves, it confirms that it is an aqueous layer). The alkyl halide was then returned to the separatory funnel. 14 mL of saturated aqeous sodium bicarbonate was added a little at a time while the separatory funnel was being swirled. A stopper was placed on the funnel and it was shaken for 1 minute while being vented frequently to relieve any pressure that was being produced. The lower alkyl halide layer was drained into a dry Erlenmeyer flask and 1.0 g of anhydrous calcium chloride was added to dry the solution. A stopper was placed on the Erlenmeyer flask and the contents were swirled until the liquid was clear. For the distillation
Solid impurities and liquid impurities having quite different boiling points are most easily removed by distillation, but even liquids having similar boiling points can be separated. For easy separations, a "simple distillation" apparatus (Figure 1) will be used for the first part, but for more accurate separations, a "fractional distillation" apparatus (Figure 2) is necessary. In this lab we will be using both apparatuses. Unfortunately, each time a distillation is run, material is lost. Some evaporates into the air and some is left behind, stuck to the apparatus. That is why fractional distillation is the best apparatus to use. It is important to keep a careful record of the temperature at the beginning and end of every fraction you collect. Stop the distillation by removing the heat just before all the liquid in the distilling flask is completely gone. Watching the rate of temperature increase is important, allowing the temperature to increase too quickly can cause impurity. The distillation curves for our simple and fractional distillation clearly demonstrate that fractional distillation separates the two compounds more
Whereas for simple distillation, the compounds need to be around 80C apart in order for proper separation to occur. Thus, cyclohexane and toluene were not able to be properly separated since the boiling point for cyclohexane was 80.74C while the boiling point of toluene was 110.6C—there two boiling points are fairly close to one another. Thus, the mole fraction for cyclohexane and toluene were fairly low when compared to cyclohexane and
Objective: The main goal of this lab is to learn how separation of binary liquid mixtures is performed. Especially when the two liquids have boiling points varying by about 30° C. Hexane can be separated from toluene in this experiment because of the difference in their boiling points. Since toluene has a higher boiling point, it will left at the bottom while the hexane starts to boil out and collect in the Hickman still. GC measurements help us in determining how accurate our data is by making a graph of the amount of hexane and toluene in each fraction. Also this lab gives experience with semi-micro
The purpose of this lab is to investigate the processes that can be used to separate two volatile liquids in a mixture based on their chemical properties. This is accomplished by fractional distillation, which separates chemicals in a mixture by differentiating them by their boiling points at atmospheric pressure. Specifically in this lab, fractional distillation is used to separate an unknown mixture into its respective pure components. The components are then identified using gas chromatography, which is also telling of the purity of the extracts and success of the procedure. The procedure of this experiment was specified in lecture by Dr. Fjetland and in Gibert and Martin’s student lab manual, Experimental Organic Chemistry: A Miniscale and Microscale Approach, 6th Edition.
Describe the use of fractional distillation to separate the components of petroleum and identify the uses of each fraction obtained.
The memo summarizes the findings from the initial assessment performed on the 190 proof SDA-3AU alcohol for use in Fractionation and downstream processes.
Distillation is a method of separating two volatile chemicals on the basis of their differing boiling points. During this lab, students were given 30 mL of an unknown solution containing two colorless chemicals. Because the chemicals may have had a relatively close boiling point, we had to employ a fractional distillation over a simple distillation. By adding a fractionating column between the boiling flask and the condenser, we were able to separate the liquids more efficiently due to the fact that more volatile liquids tend to push towards the top of the fractionating column, thereby leaving the liquid with the lower boiling point towards the bottom. After obtaining the distillates, we utilized a gas chromatograph in order to analyze the volatile substances in the gas phase and determine their composition percentage of the initial solution. Overall, through this lab we were able to enhance our knowledge on the practical utilization of chemical theories, and thus also demonstrated technical fluency involving the equipment.
There was no distillate in the distillation head after 20 minutes on the setting of 40 so the Variac transformer was turned to 45. The first fraction was collected at 55.6°C. The ratio of hexane to octane was 87.437% to 12.563%. The second fraction was collected between 47.3°C and 40.5°C. 88.429% to 11.571% was the ratio of hexane to octane for this fraction. The third fraction was collected at 30.6°C, and the ratio of hexane to octane was 94.957% to 5.043%. The contents of the conical reaction vial were placed in a fourth vial and a chromatogram was obtained for it. The ration of hexane to octane was 7.501% to 92.499%. During the collection of the three fractions, a piece of the glass pipet broke off into the distillation head. The results of the experiment could have been incorrect because the glassware was not properly cleaned. The distillate also could have collected too fast which would have lowered the separations efficiency. From this information, infer that hexane has a lower boiling point than octane because most of the distillate was hexane. The majority of what was left in the conical reaction vial was octane because the temperature was not hot enough to turn it into a gas to go into the distillation
The purpose of this experiment was to separate a two component mixture using fractional distillation. Distillation is a process of vaporization than condensation of a substance, used primarily to separate substances from a mixture when there are different boiling points. Fractional distillation is when the mixture has multiple substances with similar boiling points, and a fractional column is used to create multiple vaporization/condensation cycles. Fractional distillation is important when two or more substances need to be separated, but they have similar boiling points.
A good yield of isopentyl acetate was obtained during this experiment. Loss of the product was likely through transferring liquid from separatory funnel to the Erlenmeyer flask and residual material left in the distillation flask. Using an organic solvent like benzene or cyclohexane as a transfer agent would improve the yield, since their boiling points were around 80 oC and could be easily separated from the final product through simple distillation. However this
A 10 mL round-bottom flask was weighed both before and after approximately 1.5 mL of the given alcohol, 4-methyl-2-pentanol, was added. 3 mL of glacial acetic acid, one boiling chip, and 2-3 drops of concentrated sulfuric acid were added to the flask in that order. The reflux apparatus was assembled, the
The main objective of the distillation lab was to identify the composition of an unknown binary solution. The only known component is that the boiling point of the two components were at least 40˚C apart in boiling points. Due to the difference in boiling points, fractional distillation would be an easy way to determine the identity of each component of the binary solution. In the experiment, 30mL of the unknown binary solution was ran through the fractional distillation apparatus. As the solution boiled, gas from the unknown solution ran through the column, which had a temperature gradient to allow rapid and repeated distillations, and one of the components were isolated. By recording the temperature and amount of
Distill methanol from water using a simple distillation apparatus and fractional distillation apparatus to determine which is a more accurate form of distillation.