Gas Chromatography Lab Report

The objective of this extraction experiment was to achieve a comprehensive understanding, as well as master the practice, of the technique of separating various individual components of a compound.

There are millions of different organic compounds. Most of them are found in mixtures and in order to achieve a pure form they need to be separated, isolated, and purified. However, there are endless numbers of possible mixtures, which make it impossible to have a pre-designed procedure for every mixture. So chemists often have to make their own procedures. The purpose of this experiment was to prepare the student to the real world by them designing their own procedure which will help them understand the techniques of separation and purification better. The goal was to extract two of the components of the

Experiment 55 consists of devising a separation and purification scheme for a three component mixture. The overall objective is to isolate in pure form two of the three compounds. This was done using extraction, solubility, crystallization and vacuum filtration. The experiment was carried out two times, both of which were successful.

The boiling range of the 1-pentyl ethanoate distillate was approximately between 149-151°C. This was indicated by the formation of the distillate and when the mixture of the purified 1-pentyl ethanoate started to vigorously

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.

The purpose of this experiment was to use solvent extraction techniques in order to separate a mixture consisting of a carboxylic acid (p-toulic acid), a phenol (p-tert-butylphenol), and a neutral compound (acetanilide). Extraction is the process of selectively dissolving one or more of the compounds of a mixture into an appropriate solvent, the solution that contains these dissolved compounds is called an extract (Manion, 2004).

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.

In this experiment were used three separation techniques: extraction, sublimation and recrystallization. During the first method, 0.70 g sample of salicylic acid-naphthalene mixture was dissolved in 10 ml of diethyl ether. The solution was placed in a separatory funnel and 10 ml of saturated aqueous sodium bicarbonate solution was added to it. After the initial gas was

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

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

By using boiling point from fractional distillation, the identity was approximately distinguished. The first plateau has temperature of around 55~57℃, and the acetone’s boiling point is 56.5℃. The second plateau has temperature of around 108℃, and the Toluene’s boiling point is 110.6℃. Then, after performing gas chromatograph, the retention time classified more accurate identify of unknowns. In fraction A, the first peak’s retention time was 0.64 minutes.

Objective: The objective of this experiment is to use acid-base extraction techniques to separate a mixture of organic compounds based on acidity and/or basicity. After the three compounds are separated we will recover them into their salt forms and then purify them by recrystallization and identify them by their melting points.

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

As per the sample calculations in Appendix C, the Karr Reciprocating Plate Column effectively extracted 90.24 % of the ethanol from the Feed stream into the Extract stream. As was expected, the agitation aided in the separation process considering more surface area was made available for interface interaction with smaller droplets.

Considering the graph plotting the volume of the distillate and temperature using simple distillation, the temperature of the acetone/toluene mixture gradually increases as a greater volume is collected. If this method of distillation were effective, the temperature would remain constant as acetone reached its boiling point until all the acetate had been boiled out of the distilling flask. However, this does not occur. This is because some of the toluene was boiling and being co-distilled in addition to the acetate, so the distillate being collected wasn’t a pure distillate of acetate. Simple distillation is more effective for purifying a liquid mixture of two compounds with a wider difference between their melting points, typically a difference of at least 70 oC. However, the literature boiling point for acetone is 56 oC, and that of toluene is 110-111 oC. This is a difference of 54-55 oC, which is below 70 oC, and this explains why the simple distillation performed in this experiment was not effective. Between the time 26 and 30 mL of distillate had been collected, the temperature increased more dramatically per amount of distillate collected. This means that during this time, fewer vapors were condensing into the graduated cylinder as the temperature rose, until the temperature reached about 100 oC, at which point more vapors began condensing into the graduated cylinder once more. This is because at about 100 oC, the boiling point of toluene was reached, so the remaining