Optimization of Gas Chromatography

The objective of this experiment is to separate a 50:50 mixture of benzoic acid and benzil by using macroscale extraction. In the experiment, organic solvent diethyl ether is used. After adding 1.0 gram of the 50:50 mixture of benzoic acid and benzil to a 25ml Erlenmeyer flask, diethyl ether was added to the flask to dissolve the mixture. Benzoic acid and benzil dissolve in diethyl ether. Once the mixture dissolved in

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.

In the first acid extraction of benzocaine, the compound was dissolved in the organic solvent of dichloromethane. When the mixture was shaken with HCl, benzocaine’s amine group gained a proton and became more soluble in water than dichloromethane. This allowed the newly formed hydrochloric salt to migrate to the aqueous layer. However, the addition of NaOH to the acidic aqueous layer regenerated benzocaine by deprotonation, making it insoluble in the aqueous layer. The precipitation of an ionic salt was therefore recovered by vacuum filtration and had a tested melting point range of 85.1C-87.4C compared to 88C-90C, the literature melting point of benzocaine. The similarity in melting point ranges, but low percent yield of 30.37% proves that the extract was somewhat successful. Lower yields may be the result of spillage performed in the lab. In the second basic extraction, the organic layer now included benzoic acid and benzamide. When treated with NaOH to deprotonate benzoic acid, the newly formed sodium benzoate transitioned to the aqueous layer as a sodium salt. Benzoic acid is regenerated once again after the addition of HCl and became insoluble in the aqueous layer after protonation. Its precipitation was then filtered out for a 65.87% recovery. Compared to its literature melting point of 122.41C, the resulting 120.9C-123.5C melting range of the sample also supports the accuracy of the separation due to its similarities and high percent yield. In conclusion, the usage of base and acid liquid extraction was mostly successful in this experiment because it was able to efficiently and properly isolate the impure mixture into two separate components of benzocaine and benzoic acid. By performing the techniques of extraction and vacuum filtration, the similarities between literature and tested

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

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.

The purpose of this experiment is to practice common organic laboratory techniques inside the lab to get one oriented to the basic methods of procedure that can be used for later experiments. This experiment involves the separation of benzoic acid from a more crude form, consisting of benzoic acid, methyl orange, a common acid/base indicator, and cellulose, a natural polymer of glucose (Huston, and Liu 17-24). The technique that is used to perform this separation is called extraction. Extraction is a systematic process of separating mixtures of compounds, taking advantage of the affinity differences of compounds to separate them (Padias 128-37). This technique recognizes the principle that “like dissolves in like,” that is,

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.

Experiment 4A: Determination of a Partition Coefficient for Benzoic Acid in Methylene Chloride and Water, and Experiment 4B: Solvent Extraction I: Acid-Base Extraction Using the System Benzoic Acid, Methylene Chloride, and Sodium Bicarbonate Solution

118℃ and 118-119℃, and 126℃ respectively), when adding heat to the solution, both reactants, 1-butanol and ethanoic acid, will boil and turn into a vapour before the ester, at approximately 118℃. Therefore, their vapour will pass through the Liebig condenser and be condensed back into liquid form to be collected as a distillate before the ester. Only when the temperature reaches approximately 126℃ will the ester undergo this same process and be distilled to obtain an ester distillate. However, as the ester is distilled after the reactants, its distillate can only be collected later as a mixture with the distillates of the reactants. Moreover, as the density of 1-butanol and the ester, 1-butyl ethanoate is very similar (i.e. 0.81gmL-1 and 0.88gmL-1 respectively), it will also be hard to identify the ester layer. Hence, if a distillation set up were used for the production and collection of the ester, isolation of ester as it forms would not be

In 1941 Martin and Synge, described the discovery of liquid-liquid partition chromatography and also laid the foundation of Gas liquid chromatography and High performance liquid chromatography. They also introduced the concept of the Height Equivalent to the Theoretical Plate, which has since been adopted as the measure of Chromatographic efficiency.

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.

This lab report is based on the third experiment, and it was the Extraction: Separation and Purification Technique. The purpose of this third lab was for the lab students to understand about the process of extraction and how it can be used to separate substances. The lab students were given the mixture of the equal amounts of Aspirin (Acetyl Salicylic Acid), Acetanilide and Urea. The lab students would have to go through the process of extraction in order to separate the three compounds from each other. The goals of this the third lab was for the students to successfully separate the three compounds (Aspirin, Acetanilide, and Urea) from each other, figuring out the percent recovery and to determine the purity of the substances that were recovered.

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).

For the first part of the experiment, 1-propanol and methanol and 1-propanol mixture were used. The integral area (mV) was determined to be 1749 min*mV, but the average was found to be 1183.6 mV. The retention time was determined to be 1.565 min, but the average turned out to be 1.738 min between three groups. The findings may be off because the collect button and the substance was not inserted into the gas chromatograph at the same time. Or the data was not collected correctly. In part two of the experiment, the percent error for the calculated average atomic mass was 0.95%. The results were close to the literature value which was 83.799 amu while the calculated value was 83.42 amu. The greatest percent error was 163% when the length of one

In this experiment the objective was to analyze different compounds that moved through the Vernier Mini GC. With the assistance of a Vernier Mini GC, retention time at various temperatures could be observed. When a compound is put through the Vernier Mini GC, compounds that were more complex (non-polar, high boiling point, and molecular weight) had an extended retention time compared to simple compounds. Retention time is the time it takes for a compound to exit the column after being injected. This experiment, the retention time of different compounds were observed. Prior to completing the experiment, a hypothesis was constructed as regards to how structure affects retention time. The first part of experiment hypothesis is if the molecular