TLC was used to identify the actual unknown product as well as other products/reactants present in the filtered solution. The procedure was conducted by placing a TLC plate in a developing chamber that is filled with a small amount of solvent. The solvent cannot be too polar because it will cause spotted compounds on the TLC plate to rise up too fast, while a very non-polar solvent will not allow the spots to move. The polarity of the spots also determines how far it moves on the plate; non-polar spots are higher than polar ones. After spots on the TLC form, the Rf values are calculated and used to analyze the similarity of the compounds.
There was a lack of an OH peak for methyl benzoate spectrum, which was good because it supports the idea that this IR spectrum was for the desired product. There was a carbonyl peak at 1717.1 for the student outcome of methyl benzoate, which was probably representative of the ester group in the product. Lastly, there were a few peaks from 3064.3-2840.9 that corresponded to the methyl hydrogens and the aromatic hydrogens: they were represented
Introduction The purpose of this week’s lab was to enhance our understanding of the Grignard reagents that were examined in lecture. In this lab, a Grignard reagent will be prepared through the reaction of magnesium turnings and bromobenzene. Instead of isolating the product it will then be combined with benzophenone, which will give the final product of triphenylmethanol. Procedure
The mass of the crude product was 0.77 g, where the purified product was 0.03g. Comparing the pure product to the amount of isoborneol used, the percent yield was found to be 2.4%. To improve this low percent yield the procedure should be again be examined. Reducing the amount of product lost during transfers, filtration, and sublimation would improve yield. Better transfer would involve more through washes of glassware. Moreover, the yield of the sublimation process was very low (3.9%).
To go in more depth, 98.2% is a high yield, despite the inaccuracies due to time constraints, and the inability to the recrystallize the benzoic acid. As mentioned earlier, product might have been lost during the many filtration procedures in the experiment, as not all of the product was poured out from the flask, onto the filter. Since, recrystallization could not be done, the benzoic acid was immediately transferred onto the watch glass, and it is when transferring some product could have been left on the filter. Overall, pouring product into the filter, and trying to get every particle of product from the flask for each filtration procedure in the experiment, is rather difficult, and is impossible to get every bit of product. Another key possibility, though it fortunately did not occur in the experiment, a green, or purple result
The total amount of AlCl3 in the final product was 7.37 grams. 7.37 grams was found by subtracting the mass of the Erlenmeyer flask without the product from the mass of the Erlenmeyer flask with the product. Using Stoichiometry, the isolated product was calculated to be 73.5%. The complete sheet of work validates the calculation of the percent for the isolated
The following lab period the solid was weighed (0.0483 g) and percent yield was calculated (65.5%) with the limiting reagent being tetraphenylcyclopentadienone. The melting point was determined. The first melting point was 204-204.9 °C and the second melting point was 215.6-215.9°C. Finally, an infrared spectroscopy was obtained for the
Through the extraction process, the mixture was separated into its pure benzocaine and benzoic acid portions. This could be proven by matching the melting points of the substituents obtained at the end of the lab to the average melting points found in several chemistry databases. In other words, the melting points of the purified benzocaine and benzoic acid compounds (93.2˚C and 131˚C, respectively) reflect a similar melting points to the documented 89˚C and 122.41˚C of the pure compounds found in nature. Although, the results was collected smoothly, the possibilities of errors are still existent. One source of error could aroused when light brown clouding forms at the interface of the two layers during acid extraction of benzocaine.
This appearance does not have any negative implications though. The experiment was carried out smoothly with no errors. Nevertheless, some mass could have been loss during the heating or during the transfer of the crystals into a vacuum filtration apparatus. When the dried crystals were collected from the Buchner funnel, some product was also lost. The loss of crystals was not significant though, as a decent percentage was found for the percent yield.
The purpose of this experiment was to perform elimination reactions with two different bases: potassium hydroxide and potassium t-butoxide. We explored the principles of dehydrohalogenation, Zaitsev’s rule, Hofmann’s rule, and elimination. Using these strong bases eliminated problems that could arise due to by-products produced by substitution reactions, and also allows a study of effects on the product ratios because one base is stronger than the other and has different steric requirements and molecular structure. In comparing the ratios of the different products produced by potassium hydroxide and potassium t-butoxide, we learned how different solvents and reagents affect the course and outcome of a chemical reaction. Reaction Scheme Theory Reaction Mechanism
Introduction Research in chemistry incorporates both microscopic and macroscopic properties. Essential to the properties compounds have both molecularly and environmentally is the ions and metals that make up many compounds. The properties of these chemicals depend heavily on the atoms that make up each particular chemical. Whether the compound is monoatomic, polyatomic, or even a polymer, being able to identify a compound is an essential tool in being able to make predictions and assumptions about the properties a specific chemical may have. Take for example the research being done on phosphorous and fluorine during World War II in Germany and during the Cold War which were able to be used as weapons, or during the early 1930’s when Germany
However, after refluxing for a while, yellow precipitates begin to form near the top of the flask. It was assumed that the remaining starting material was concentrated from a decrease volume to reappeared in solution. Nevertheless, this may have been a sign of contamination that will negatively affect the entire reaction. This observation later resulted in a yellowish
This supports the isolated product is majority made of the desired product and is largely pure. Mass spectrometry of the crude product shows the molecular ion peak is 162.1, which is the largest fragment in the mass spectrum (Figure 4) and corresponds to the molecular weight of methyl trans-cinnamate (Table 1). The base peak is 131, inferring the fragment lost is 31 m/z in size. This 31 m/z matches the OCH3 fragment of the ester, and would not result from a trans-cinnamic acid. This is evidence the product was successfully