Column Chromatography Lab Report

1.5ml of nitric acid was added to .30g of benzoin in a conical vial with a stir vane. The mixture was then heated in a 70 degree Celsius water bath, while stirred, for one hour. The mixture in the conical vial was then cooled to room temperature and, using a pipette, the solution was transferred to a beaker containing 4ml of ice water. The mixture slowly crystallized in the beaker and the crystallized product was filtered on a hirsch funnel with vacuum. 5 ml of cold water was used to wash the product and then the product was allowed to dry.

The objective of this lab is to synthesize acetaminophen from p-aminophenol. The techniques used to do so, consist of: reflux with heat to allow reaction to occur at a reasonable time period, extraction and filtration to isolate the desired product, and characterization of the product by analyzing IR spectras and melting points. Acetaminophen considered synthesized, primarily due to the IR spectrum exhibiting all the bond vibrations is the amide group. The percent yield of 124.6% imply that there was a mechanical error that occurred, thus, also tampering with the progression of the chemical reaction. The wide melting point range of 165 C-169 C denote the impurity of the acetaminophen product.

In the following reaction, benzil was rearranged to from benzilic acid by reacting it with potassium hydroxide in ethanol. 0.100 benzil was utilized and the theoretical yield of benzilic acid was 0.109 grams (see Eq 5). The final yield and weight of benzilic acid was 0.60 grams. The final yield and theoretical yield were used to calculate the percent yield, 55% (similar to Eq 3). The melting point of benzilic acid was 148.3C and the literature value for

The purpose of refluxing the reaction was to break the bond in the p-acetaminophen and acetic anhydride at the same time the condenser prevent some molecule to escape though evaporation by capturing it and return it into the reaction vessel. The heat was necessary to break bond in P-acetaminophen and in acetic anhydride by increasing the rate of reaction and bringing molecules closer to the activation energy. Product isolation was performed by cooling the solution, and filtered it to isolate the crystals of the products by using Hirsch funnel. This crude product was then purified through recrystallization technique and by using Craig tube. The final process was to identify the product by using dig melt machine to find out the melting point

The ethyl (3-oxo-2,3-dihydro-4H-1,4-benzothiazin-4-yl)acetate 4C (0.05 mol, 14.37g) was warmed in a mixture of ethanol and DMF (1:2) to get a clear solution and was cooled to room temperature. A solution of KOH (0.08 mol, 4.81g) in water (10 ml) was added to this solution and the mixture was stirred for 24h at room temperature to ensure the completion of the reaction. The completion of the reaction was monitored by TLC (CHCl3:MeOH, 9:1). The reaction mixture was evaporated to dryness and the residue dissolved again by adding ice cold water. The insoluble impurities were separated by filtration and the filtrate was acidified with 4N HCl to get a solid product (3-oxo-2,3-dihydro-4H-1,4-benzothiazin-4-yl)acetic acid (4D), collected by filtration.

The goal of this lab was to synthesize benzocaine by utilizing Fischer esterification, reflux, and melting point determination techniques. These techniques were successfully performed and the synthesis was successfully performed. Although, the synthesis was not very efficient due to the low percent yield of the product (28%) and the melting point of the product not correlating to that of benzocaine.

The 4-nitrobenzoic acid product had a percent yield of 48.89%, showing a very high yield out of 50%. The melting point range was from 236-238°C, whereas the literature value is 237-240°C. The melting point of the product was very close to the literature value and also had a narrow range, indicating a pure product and therefore deeming recrystallization unnecessary. However, if the acid need to be purified, methanol would be used as the recrystallizing solvent.

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Ethanol (3.5 mL, ...M) was added to Benzoin (...g) followed by an addition of sodium borohydride solution to the suspension of Benzoin in ethanol. The mixture was then heated with swirling. After the benzoin in the mixture was dissolved, it was heated for further 1-2 minutes with occasional swirling. The hot solution was then diluted with water. The suspension was then chilled and the product was collected by vacuum filtration. The product was then further recrystallized from the minimum amount of hot ethanol to give colourless glistening plates. (....g, % yield), m.p.

The objective of this experiment was to calculate the lower concentration limit of detection and detection threshold through instrumental analysis and human psychophysics, respectively. These values were then statistically compared to determine the superior method and inherent advantages/disadvantages were reviewed.1 Gas chromatography (GC) is a critical tool in a wide array of applications relating to food analysis, for the separation of various compounds (especially volatiles) within a mixture is typically essential in the characterization of inherent aroma compounds and undesirable defects of a given food product. Therefore, accurate quantification/qualification using GC/human psychophysics is a crucial aspect of the research and development

Chromatography Investigation Chromatography is a highly regarded technique used to separate the components of a mixture. It is based on the principle that each component possesses a unique affinity for a stationary phase and a mobile phase. The components that are more inclined to enter the mobile phase will migrate further on the chromatogram and distinguish themselves from the other components. The type of solvent used in chromatography is known to directly affect the separation of the mixture. In this experiment, thin-layer and column chromatography will be utilized to separate the numerous chlorophyll and carotenoid pigments of a spinach extract.

After all additional product ceased to form, the reaction mixture was cooled in an ice bath to allow precipitation of benzopinacol. The final product was then filtered off from the solution using a Buchener funnel. Its melting point, yield and infrared spetrum was then obtained.

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Gel-Filtration Chromatography is a commonly used method used in order purify a protein from a mixture, by means of separations. Different biomolecules differ in size, or their molecular weight. In the gel matrix inside the chromatography column, there are gel beads which are porous to allow certain sized molecules to enter. The molecules that are able to enter the pores of the gel, are held in stationary phase and will elute from the column later on, these are usually smaller, to medium sized molecules. Larger molecules that are not able to fit in the pores will elute out of the column first, they are involved in mobile phase where they just go straight through the column without interacting with the gel beads. Smaller molecules will have a higher elution volume, while the larger molecules will have a lower elution volume. The volume to elute the protein is inversely proportional to the molecules size.

It can be concluded that column chromatography is an effective way of separating components of a mixture. The crude pigment was sent through the column however three distinctly separate layers were collected (yellow, green-blue and blue). Each coloured layer represented a different pigment. It was made clear by the column chromatography that the beta-carotene (yellow) is the least polar pigment, chlorophyll b (green) is the most polar and chlorophyll a (blue-green) is intermediately polar based on the order the pigments were eluted. In the column, the least polar pigment eluted first as it adhered best to the 8:2 pet ether: acetone mobile phase. The last pigment that passed through was chlorophyll b as it was the most polar and adhered greatly to the silica. The effectiveness of column chromatography was confirmed using thin layer chromatography. On the silica plate, a spot was added for each separated pigment and the crude pigment. A highly effective separation using column chromatography would show corresponding distances travelled for the three separate colours and the three spots the crude separated into on the TLC plate. This confirmed that the column separated the pigments into the correct three layers. On the TLC