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Essay about thin layer chromatography
Essay about thin layer chromatography
Essay about thin layer chromatography
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In this experiment, column chromatography and thin layer chromatography were used to separate a mixture of fluorene and 9-fluorenone. These two methods were then compared, and the results were analyzed. In column chromatography, 0.1010 g of mixture was separated. During the separation, fluorene eluted first. This compound was white in color once dried with the rotary evaporator. A percent yield of 93.47% was calculated for fluorene. The product that eluted first was confirmed to be fluorene by the IR spectrum obtained and the experimental melting point. The IR spectrum RM-02-CC1 was the spectrum obtained for this compound. Aromatic carbon- hydrogen bonds, carbon-carbon double bonds and hydrogens attached to sp2 carbons were shown by peaks 3038 …show more content…
The IR spectrum RM-02-CC2 was obtained. The spectrum consisted of a carbonyl peak, an aromatic carbon-carbon double bond peak, and a sp2 hybridized carbon and hydrogen bond peak at 1713, 1598, and 734. These functional groups are all present in 9-flourenone. The carbonyl group specifically was important because fluorenone was the only that contained a carbonyl group. The Identity was further confirmed by the melting point, 79-80˚C. This value is similar to the known value 84˚C2. The melting point observed during the experiment is greater than the known because the sample is slightly impure. This impurity is caused by presence of fluorene on the tip of the columns. As stated before, the tip of the column needs to be manage to ensure pure products. The presence of fluorene would increase the temperature as seen in the melting point results because the melting point of this compound is greater than fluorenone. Overall, both compounds were separated with column chromatography and presented reasonable yields for both products. Column chromatography is a useful technique to separate mixtures with both large and small quantities. Unlike TLC, column chromatography and be used for large amounts of
Fluorescence measurement provides very important information about the photochemistry of a particular molecule. The first part of this experiment was dealing with the fluorescence behavior of a Leucophor PAF. Information from both spectrophotometry and fluorimetry was used to measure the quantum yield as well as to explain why Leucophor PAF was use as commercial optical brightener. The second part of this experiment dealing with fluorescence quenching of quinine bisulphate solution (QBS) is the presence of sodium chloride.
Therefore, the gas chromatography could not be performed to determine its composition. The ratio of the three samples obtained, were not all accurate. The first sample, of pure hexane should have had a ratio close to 100% hexane to 0% heptane. The second ratio should have been close to 50% hexane to 50% heptane and the third should have been the reverse of the first sample, with 0% hexane to 100% heptane. The boiling point of hexane is around 65°C and the boiling point of Heptane is 100°C. The first sample’s error could have occurred due to the late extraction of the sample. When the boiling point was reached, the extraction of the sample from the distillation vial should have occurred immediately, not doing so caused some of the vapors from heptane to be included into the first sample. This could be prevented next time by lowering the heat of the Variac transformer, which would have allowed for the heating of the compound to be slower than what it was
Separations are important techniques in chemistry that are used to separate various components of a mixture. They are carried out by mixing two immiscible liquids containing certain solutes together in a separatory funnel, allowing them to separate, then extracting the distinct layers that form. The ratio of the concentration of solute present in the upper layer to the concentration in the lower layer is called the partition coefficient. The efficiency of a separation is described by this partition coefficient. If the coefficients for the two layers are largely different, then the separation can be carried out in a single step. If they aren’t, a more complex process is necessary.1,2 Countercurrent chromatography is a technique used carry out separations in these kinds of cases. It uses a continuous liquid-liquid partitioning process to streamline the usual extraction procedure.
Rogers, D. H.; Morris, J. C.; Roden, F. S.; Frey, B.; King, G. R.; Russkamp, F. W.; Bell, R. A.; Mander, L. N. Pure Appl. Chem., 1996, 68, 515.
The purpose of this experiment is to learn how to use fractional distillation to separate a mix of isopropyl acetate and toluene, redistill them, and use gas chromatography to examine the separation.
Discussion The reaction of (-)-α-phellandrene, 1, and maleic anhydride, 2, gave a Diels-Alder adduct, 4,7-ethanoisobenzofuran-1,3-dione, 3a,4,7,7a-tetrahydro-5-methyl-8-(1-methylethyl), 3, this reaction gave white crystals in a yield of 2.64 g (37.56%). Both hydrogen and carbon NMR as well as NOESY, COSY and HSQC spectrum were used to prove that 3 had formed. These spectroscopic techniques also aided in the identification of whether the process was attack via the top of bottom face, as well as if this reaction was via the endo or exo process. These possible attacks give rise to four possible products, however, in reality due to steric interactions and electronics only one product is formed.
The isomerization procedure was done in order to create dimethyl fumarate from dimethyl maleate. Dimethyl maleate and dimethyl fumarate are cis and trans isomers, respectively. This procedure was done via a free radical mechanism using bromine. The analysis of carvones reaction was done in order to identify the smell and optical rotation of the carvone samples that were provided. The odor was determined by smelling the compound and the optical rotation was determined using a polarimeter.
The crude extract obtained by solvent extraction was subjected to various qualitative tests to detect the presence of common chemical constituents as:
The Thin layer chromatography is one of the oldest techniques which is used to identify what is present in an unknown mixture. It is a very useful technique for research,forensics,environmental testing, and many more fields because it is simple and inexpensive way to analyze small samples. In this experiment two compounds (solid) were used ferrocene and acetylferrocene. In the first step 50 ml of 2:8 diethyl ether/petroleum ether was placed in an erlenmeyer flask covered with a parafilm paper to avoid evaporation. Then the glass column was prepared placing a small cotton on the bottom of the glass column and then added a small amount of sand , wich will give the stationary phase an even base and prevent concentration and streaking of the bands
The purpose of this experiment was to test for quality control and analysis of a commercial product, in this case vinegar. The experiment performed determined the actual molarity of a specific brand of vinegar as compared to information provided on the bottle. The standardization of HCl and NaOH was also performed in order to understand the process of titrations. The importance of testing for quality control to be sure the product being sold holds up to its commercial value and is authentic in what it advertises to be. Quality control is a way to test the standards of a commercial product by testing a sample of the output against original specifications. Quality control is also used to protect public health and ensure the safety
In conclusion Gas Chromatography has many uses to separate and analyse compounds and to be able find separate components in a mixture to identify any unknown components. Because of it's simplicity and effectiveness it is one of the most important tools to chemistry. Like most analytical techniques it has its advantages such as not being harmful to the sample be used and disadvantages such as not being particularly use with liquids that change temperate easily.
The combination of the separation technique of LC allows pure compounds to enter the identification by mass spectrometry and therefore increases the chance of successful identification of an unknown substance. This is based on the principle that many compounds with identical retention characteristics have different mass spectra and in this way can be differentiated. The...
Figure 2 also shows that when a solvent is used that is lighter than water, density < 1, the organic phase will be on the top in the separatory funnel, while solvents denser than water, density > 1, will sink to the bottom of the funnel (2). The success of the separatory funnel technique allowed for Thin Layer Chromatography (TLC) and Infrared Spectroscopy (IR) analysis.
Chromatography and electrophoresis are used for many wonderful processes that take place in labs. Chromatography and electrophoresis are separation techniques employed by chemists. Chemists execute multiple chemical tasks daily therefore they must find the most efficient ways to carry out these functions. Even though electrophoresis has some benefits, Chromatography is more useful than electrophoresis because it is more versatile and can be widely used in research; chromatography should be used more than electrophoresis in scientific research because it is more effective in a lab setting and can be used in more fields.
The purpose of this particular experiment is to acquire the product 4-methylcyclohexene from the reactant 4-methylcyclohexanol by altering the equilibrium and using an elimination (E1) reaction involving dehydration with a strong acid acting as a catalyst. The following techniques and analyses were utilized in this experiment: simple distillation, “salting-out” the crude product, neutralization, unsaturation test, and infrared spectroscopy. Simple distillation is necessary for separating a liquid mixture and collecting the purified product or desired result. “Salting-out” the crude product was employed as a means of an extraction and purification process; that is, the salt would extract the water from the mixture, which leads to a reduction in solubility of the organic compound.