Observations The purpose of this experiment was to be able to synthesize triphenylmethyl bromide from triphenylmethanol by a trityl carbocation intermediate. During the experiment, 0.100 g of triphenylmethanol was placed into a small test tube. The triphenylmethanol looked like a white powder. Next 2 mL of acetic acid was added to the test tube and the solution turned a cloudy white color. There was a strong odor similar to the smell of vinegar given off. After the solution was heated and the solid dissolved, 0.2 mL of hydrobromic acid was added to the test tube. The solution turned a bright yellow color after the hydrobromic acid was added. The solution was heated in a hot water bath for 5-10 minutes and then let cool. After heating, the …show more content…
After adding the acetic acid and hydrobromic acid to the solution, and heating and recrystallizing the solution, the product triphenylmethyl bromide was created and had a mass of 0.103 g. The theoretical yield was calculated by determining the limiting reagent in the reaction. The triphenylmethanol was the limiting reagent in the reaction. The total amount of mass from the triphenylmethanol was converted to moles by using the molar mass of the triphenylmethanol. The amount of moles was then converted into grams to determine the theoretical yield, 0.125 g. The percent yield was then calculated by dividing the actual yield by the theoretical yield and multiplying the result by 100%. The percent yield was 82.4%. The melting point of the product was observed to be 139.5 °C. The theoretical yield of the product is 152 °C (University of South Carolina Department of Chemistry and Biochemistry). The melting point percent difference was calculated by subtracting the theoretical melting point from the actual melting point, dividing the result by the theoretical melting point, and multiplying the result by 100%. The melting point difference was 8.22%. Example calculations are shown …show more content…
Since triphenylmethanol is a tertiary alcohol, it went through an SN1 reaction where a carbocation was formed in order for the covalent bond to form. Compared to SN2 reactions, SN1 reactions are composed of three steps with the carbocation in the rate determining step. An important every day example of an SN1 reaction is the digestion of carbohydrates by glycosidase. This is an SN1 reaction where water is the nucleophile and and an alcohol is the leaving group. Humans use this process to break down carbohydrates for an energy source. Other biological organisms use this same process such as cows that break down cellulose through an SN1
Grignard is a reaction that is crucial to forming the new carbon-carbon bond. This is a two-part lab that teaches new techniques; the purpose of this lab is to introduce realistic organic synthesis and apply acid workup to produce triphenylmethanol. A Grignard reaction is characterized by the addition of a magnesium halide (an organomagnesium halide) to an aldehyde or a ketone in order to form a secondary or tertiary alcohol. These reactions are helpful because they serve as a crucial tool in performing important carbon-carbon bond-forming reactions (Arizona State University, 2018). This experiment aimed to observe the mechanisms of a Grignard reply to synthesize triphenylmethanol from benzophenone using phenylmagnesium bromide as the Grignard reagent.
In this test, primary halides precipitate the fastest while secondary halides need to be heated in order for a reaction to occur. Comparison of the rates of precipitation of the obtained product to standard 1° and 2° bromide solutions will show whether the product is a primary or secondary
The goal of experiment four was to use sodium dichromate to oxidize borneol to camphor. To purify the camphor use sublimation, then reduce camphor to isomeric alcohol isoborneol with sodium borohydride. Use the 1H NMR to determine the ratio of borneol to isoborneol in the final product. The experiment was carried out by using sodium dichromate to oxidize a borneol solution that was made with borneol and ethyl acetate. Once the reaction was complete the mixture was transferred into a separatory funnel where the ether and aqueous layers were separated and the aqueous layer was then extracted with two portions of ether.
In addition, phenolphthalein was added as an indicator. The aliquots were titrated against sodium hydroxide (NaOH) solution until end point was reached, after which volume of NaOH consumed was recorded. The value of the rate constant, k, obtained was 0.0002 s-1. The experiment was then repeated with 40/60 V/V isopropanol/water mixture and a larger value of k = 0.0007 s-1 was obtained. We concluded that the rate of hydrolysis of (CH3)3CCl is directly proportional to water content in the solvent mixture.
The hydrogen removed must be anti to the leaving group. The mechanism of E2 reaction has only one steps, which is displacement of leaving group by removing hydrogen. The rate of the E1 elimination is based on substrate only, while it depends on both substrate and base in E2 elimination. E1 elimination is favored by weak base and ptotic solvents, while E2 is favored by strong base, high concentration of nucleophile and aprotic solvents. The major product of E2 elimination is the more substituent alkene, while the products of E1 elimination are trans-cis alkene and terminal
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
Vacuum filtration was performed on the crude product, then it was recrystallized for purification. Melting point analysis was conducted on the recrystallized product to determine its identity. 3. The three possible mechanisms in this experiment were syn-addition
Enzymes are an important part of the cell and are crucial to sustaining a healthy life for an organism. An enzyme is a protein, composed from amino acids, and an enzyme’s role in the cell is to increase the cell’s ability to perform chemical reactions (Brain 2000). The chemical reactions that cells perform are critical to the development of cells and are how cells grow (Brain 2000). Tyrosinase is an enzyme that is commonly found in plants, and its function is to cause plants to brown, a process known as melanization (Chang 2012). Dihydroxyphenylalanine (DOPA) is an amino acid that reacts with Tyrosinanse, and this reaction eventually leads to create melanin, a product of melanization (Waite 1991).
As seen in table 1, the theoretical yield was .712 g of C_17 H_19 NO_3. The % yield of this experiment was 7.51 % of C_17 H_19 NO_3. . This low yield can be explained from a poor recrystallization technique combined with potential contamination. Throughout the experiment, the mixture changed color from green, orange, to yellowish lime, and eventually clear.
The yellow solution containing the reactants was slowly poured into the beaker containing the cold water and the acid in order to cause the precipitation of the alcohol, 9-fluorenol and to destroy (hydrolyzed) the unreacted excess sodium borohydride. Subsequently, the white precipitate was vacuum filtered and washed twice with 20.0 ml portions of distilled cold water by pouring the liquid into the Buchner Funnel during filtration. It was necessary to wash the alcohol prior to recrystallization considering that the C-OH bond is easily broken by the formation of a stable and benzylic carbocation that favors the synthesis of difluorenyl ether. Finally, before the purification by recrystallization of the obtained product, the white solid alcohol was allowed to dry over a period of a
(150.22g/mol)(3.5 x 10^-3 mol of nucleophile) = 0.525 g Actual yield = 0.441 g, Percent Yield = (0.441g/0.525g) x 100% = 84% 10. Percent recovery from recrystallization = (0.172g/0.441g) x 100% = 38% 11.
thanol is the desired product for the experiment, and it can be produced in various methods. Traditionally, it can be produced by the fermentation of sugar, starches, or cellulose. Synthetic ethanol can also be produced from ethene with the use of steam and catalyst. In scheme 1, it shows the reaction of how ethene converts into ethanol. Using catalyst, often time H3PO4, and running the reaction in 300°C with high pressure and high steam, ethene will react with water and produces ethanol.
The literature melting point range of methyl trans-cinnamate is ~34-38oC (Aldrich).4 The obtained melting point of the crude was 34.5-35.5oC, which is a highly narrow range of less than 1oC difference and it also falls within the expected melting point range. Hence, the crystal lattice structure of the product is largely intact, requiring an even amount of thermal energy to melt the sample. The experimental melting point range indicates the crude product is relatively pure with minimal impurities. The percent yield was satisfactory, having a 68% yield. To optimize this yield, consider the steps in how the reagents are introduced to the reaction mixture in terms.
The final product weight for percent yield was only the solid E product, which missed one half of the final product produce. If both products were weight, the percent yield would have been larger that it was. Instead of 22.33%, it could have been 44.66%. To prove that both products were obtained, but only one of the two products was analyze, a TLC plate of the DCM layer, that contains both products, and of the final product, was obtain.
Abstract The unknown concentration of benzoic acid used when titrated with standardized 0.1031M NaOH and the solubility was calculated at two different temperatures (20◦C and 30◦C). With the aid of the Van’t Hoff equation, the enthalpy of solution of benzoic acid at those temperatures was determined as 10.82 KJ. This compares well with the value of 10.27KJ found in the literature.