Gas Chromatography Lab Report

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

In this experiment, we used distillation to separate a mixture of cyclohexane and toluene. We used two types of distillation simple and fractional. The experiment was carried out by mixing the cyclohexane and toluene in a round bottom flask, and the mixture was heated to boiling (in sand bath) and vaporized. The vapor then condensed by the condenser where the water was running through to cool the vapor back to liquid. Since this was a mixture of two liquids, the temperature was continuously increasing throughout the process. The different boiling points of cyclohexane and toluene allows the separation to occur. Cyclohexane has a boiling point of 81 °C and toluene has a boiling point of 111 °C, since cyclohexane has a lower boiling point it

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

This experiment was done in order to understand both fractional distillations and gas chromatography. In addition, this experiment was done to separate and identify two liquids that made up an unknown mixture. Gas chromatography was used to figure out the ratio of these two liquids.

The purpose of this lab is to separate a mixture and determine the percentages of each of the ingredients. Each substance will have a different boiling point due to its intrinsic properties and from that, we will be able to determine the purity of different products as we evaporate off the next level of product.

The purpose of this experiment was to perform a simple distillation as well as a fractional distillation and to determine the composition of an unknown solution using fractional distillation.

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 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.

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 solvent moves through the stationary phase by capillary action (it is attracted to the thin layer of water in the cellulose) and picks up the molecules that are attracted to it. To determine the level of separation of the mixture, Rf values are used. Rf values are given by the ratio of the distance the dye travels divided by the distance the solvent travels. The farther the dye travels, the more attracted it is to the solvent and the greater the Rf value. Water is the best solvent to separate the dyes because it is the most polar of all the solvents and it is attracted to ions (forming an ion dipole moment.)

There are several different methods administered in order to separate volatile compounds from each other in a mixture. For example, simple distillation is commonly used to separate a liquid and solid mixture, or a liquid and liquid mixture, as long as the difference between the each boiling point is greater than 40-50%. However, if the difference of the boiling point of the compounds is not at least 40-50% then fractional distillation is used. In this lab, fractional distillation is used to isolate an unknown liquid in order to determine its identity.

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.

The extracted organic compounds were analyzed by use of gas chromatography coupled to a mass spectrometer. The sample extracts were injected into a Gas Chromatograph (Agilent 6890) fixed with a capillary column (DB-35MS). The Mass spectrometer used was an Agilent 5973 detector. The temperature of the column was first set at 70 degrees centigrade for 1 minute, then increased at a rate of 10 degrees per minute up to 300 degrees then held at that temperature for 10 minutes. The ion source & the transfer line were held at temperatures of 250oC and 280oC respectively.

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