The goal of this experiment was to convert 2-methylcyclohexanol into 1-methyl-1-cyclohexene, 3-methyl-1-cyclohexene, methylenecyclohexane, and water through the addition of phosphoric acid and sulfuric acid. This was done through distillation where a mixture of 2-methylcyclohexanol, phosphoric acid, and sulfuric acid was distilled for 30 minutes in a reflux apparatus. Sulfuric acid being a strong acid acts as a catalyst in this reaction. Phosphoric acid also acts as a catalyst in this reaction. The distillate was then added to a centrifuge tube along with 1-2 ml of saturated sodium chloride. The bottom layer in the centrifuge tube was then extracted and dried using anhydrous sodium sulfate. This bottom layer was then distilled again in …show more content…
The product that is formed the most is 1-methyl-1-cyclohexexene because it is the most highly substituted and thus the most stable, while 3-methyl-1-cyclohexene and methylenecyclohexane are produced less because they are less highly substituted and thus less stable. This reaction proceeded through an E1 pathway. In the mechanism the sulfuric acid provides a proton which protonates the hydroxyl group on the 2-methylcyclohexanol. This forms a good leaving group on the 2-methylcyclohexanol which leaves the compound as water. A carbocation results and H2PO4^- deprotonates a hydrogen on a carbon atom next to carbon atom with a positive charge resulting in alkenes with the major and minor products. One major technique used in this experiment was distillation. The reason distillation works is because different organic compounds have different boiling points. Usually a mixture containing two compounds is placed in the round bottom flask in the distillation apparatus. When the distillation apparatus is turned on and heat is applied, the vaporization of the compound in the mixture with the lower boiling point occurs. This compound, then condenses in the condenser and is received by the receiving flask at the end of the distillation …show more content…
Based on the data it appears that 1-methyl-1-cyclohexene had the highest retention time while 3-methyl-1-cyclohexene had the lowest retention time. The area of the 1-methyl-1-cyclohexene is the greatest at 46.75314%, followed by the area of 3-methyl-1-cyclohexene at 16.59539%. The area of the methylenecyclohexane is the lowest at 1.99052%. The results seem to be accurate since the major products formed in this reaction are 3-methyl-1-cyclohexene and 1-methyl-1-cyclohexene. The GC shows that the areas for these two compounds are also the greatest. The minor product formed was methylenecylohexane and its area is the smallest based on the GC. Since it is a minor product, it is logical that it has the smallest observed area of all the products formed. The experiment was started with 6.678 grams of 2-methyl cyclohexanol. As such, based on the theoretical yield calculation, 5.590 grams of the final product should be obtained. In the experiment 3.810 grams of the final product were obtained giving a theoretical yield of 68.15%. Some explanations as to why the percent yield was not ideal could have been the reaction not going to completion during the reflux step, or some quantity of the product being lost when it was transferred from the receiving flask in the distillation apparatus, to the flask
Then the reaction tube was capped but not tightly. The tube then was placed in a sand bath reflux to heat it until a brown color was formed. Then the tube was taken out of the sand bath and allowed to cool to room temperature. Then the tube was shaken until a formation of a white solid at the bottom of the tube. After formation of the white solid, diphenyl ether (2 mL) was added to the solution and heated until the white solid was completely dissolved in the solution. After heating, the tube was cooled to room temperature. Then toluene (2 mL) was added to the solution. The tube was then placed in an ice bath. Then the solution was filtered via vacuum filtration, and there was a formation of a white solid. Then the product was dried and weighed. The Final product was hexaphenylbenzene (0.094 g, 0.176 mmol,
The purpose of this lab was to perform an electro-philic aromatic substitution and determine the identity of the major product. TLC was used to detect unre-acted starting material or isomeric products present in the reaction mixture.
The goal of this two week lab was to examine the stereochemistry of the oxidation-reduction interconversion of 4-tert-butylcyclohexanol and 4-tert-butylcyclohexanone. The purpose of first week was to explore the oxidation of an alcohol to a ketone and see how the reduction of the ketone will affect the stereoselectivity. The purpose of first week is to oxidize the alcohol, 4-tert-butylcyclohexanol, to ketone just so that it can be reduced back into the alcohol to see how OH will react. The purpose of second week was to reduce 4-tert-butylcyclohexanol from first week and determine the effect of the product's diastereoselectivity by performing reduction procedures using sodium borohydride The chemicals for this lab are sodium hypochlorite, 4-tert-butylcyclohexanone
Alcohol, which is the nucleophile, attacks the acid, H2SO4, which is the catalyst, forming oxonium. However, the oxonium leaves due to the positive charge on oxygen, which makes it unstable. A stable secondary carbocation is formed. The electrons from the conjugate base attack the proton, henceforth, forming an alkene. Through this attack, the regeneration of the catalyst is formed with the product, 4-methylcyclohexene, before it oxidizes with KMnO4. In simpler terms, protonation of oxygen and the elimination of H+ with formation of alkene occurs.
While the solution is being stirred, an air condenser is attached to the vial and 12.2 mg of NaBH4 is added in 3 portions through the condenser. The condenser is capped with a drying tube containing calcium chloride and cotton. After thirty minutes a TLC analysis is taken of the reaction to see how many compounds are present. Three compounds were identified on the TLC meaning that the reaction did not go to completion and the mixture was placed back on a hot plate to react further for ten minutes longer. The TLC showed the starting product 4-tert-butylcyclohexanone and the cis-/trans- forms of 4-tert-butylcyclohexanol; the cis isomer is more polar and will appear above the trans
barbier reaction: In a 50 mL round bottom flask that had a reflux condenser attachment, saturated ammonium chloride (5 mL), THF (1 mL), zinc powder (0.4 g), benzaldehyde (0.500 mL, 0.5225 g, 4.92 mmol), and allyl bromide (0.470 mL, 0.6533 g, 5.40 mmol) were charged with stir bar and stirred at room temperature for 45 minutes. Diethyl ether (10 mL) was added to the reaction mixture and stirred. The mixture was gravity filtered into a beaker that was topped with a watchglass. The filtrate was transferred to a separatory funnel and the organic layer was extracted with deionized water (10 mL) and diethyl ether (15 mL). The organic layer was placed into an Erlenmeyer flask and the aqueous layer was placed into a beaker, which was extracted with
Hydration of alkenes is characterized by the addition of water and an acid-catalyst to a carbon-carbon bond leading to an alcohol. Dehydration is exactly the opposite in which dehydration of an alcohol requires water to be removed from the reactant. Equilibrium is established between the two processes when the rate of the forward reaction equals the rate of the reverse reaction. The alkene that is used in this experiment is norbornene. Through hydration of norbornene, an alcohol group should be present on the final product yielded what is known as exo-norborneol. Percent yield is a numerical indication of how much of the reactant was actually reacted to yield product. The equation for percent yield is shown below:
Another simple improvement to the experiment could have been the addition of time to procedure A as well as possibly increasing the time heated under reflux. Since the entire procedure B had to be completed before the period of reflux was done, some of the steps and processes involved in procedure B were rushed or not given the adequate time allowed to produce the best sample of product. In general, the laboratory experiment was successful and turned out well to find that the bromide ion was the better nucleophile to both the n-butyl alcohol as well slightly toward the t-pentyl alcohol used in the
The three butene products have been verified to elute in the following order: 1-butene, trans-2-butene, and cis-2-butene. Theory: The dehydration of 2-butanol, a secondary alcohol, progresses readily in the presence of a strong acid like concentrated sulfuric acid (H2SO4). The reaction is completed via the E1 mechanism. Initially, the hydroxyl group is a poor leaving group, but that is remedied by its protonation by the acid catalyst (H2SO4) converting it to a better leaving group, H2O. The loss of this water molecule results in a secondary carbocation intermediate that continues to form an alkene in an E1 elimination.
All the reagents and solvents were obtained from standard suppliers. The 2:1 water:methanol was prepared by the Carleton College stockroom and methanol was degassed with argon with the use of a Schlenk Line, but the rest of the reagents and solvents were used with no further purification. The final step of the synthesis was performed in an inert atmosphere provided by a Schlenk Line. The 1H and 13C spectrums and COSY, DEPT, and HMQC experiments were collected with a Bruker Avance III HD 400 MHz High-Performance Digital NMR Spectrometer.
In this lab 2-methyl-butyn-2-ol is hydrated to 3-hydroxy-3-methyl-2-butanone. This process was preformed by using a strong acid which created an enol, and then the enol tautomerized. Due to this being a terminal alkyne, only one product will be formed. Techniques such as simple distillation, reflux, and gravity filtration were used to produce and separate the product from the mixture that it was in. When performing this lab using only one equivalent of alkyne produced a low percent of 1%. The low yield is a result of using one equivalent instead of two.
The joints were greased well to prevent vapor loss. 15 mL of the sample used and two boiling chips were placed in the distilling flask. The flask was heated with a hotplate in an oil bath. In separate, numbered, and calibrated test tubes, 0.5 mL of the distillate were collected while the temperature was recorded when each fraction was collected. The distillation was stopped when the temperature reached above 90˚. The set-up was cooled and the remaining liquid in the distilling flask were poured into a graduated cylinder. The volume was recorded. The temperature reading versus the volume of distillate were now plotted. The percent ethanol was computed.
The conical vial was placed in a small beaker and allowed to cool to room temperature. The mixture was Cooled thoroughly in an ice bath for 15-20 minutes and crystals collected by vacuum filtration on a Hirsch funnel. The vial was rinsed with about 5 mL of ice water and transferred into to the Hirsch funnel and again washed with two additional 5mL portions of ice water. Crystals were dried for 5-10 minutes by allowing air to be drawn through them while they remained on the Hirsch funnel. The product was transferred to a watch glass plate and allow the crystals to dry in air. Crude acetaminophen product was weighed and set aside a small sample for a melting point determination and a color comparison after the next step. Calculation of the percentage yield of crude acetaminophen (MW = 151.2). was done and recorded in the lab notebook.
The sample was subjected to steam distillation as illustrated in Figure 1. A total of 50ml of distillate was collected while recording the temperature for every 5.0 ml of distillate. The distillate was transferred into a 250ml Erlenmeyer flask and 3.0 g of NaCl was added. The flask was cooled and the content was transferred into a 250-ml separatory funnel. Then 25.0ml of hexane was added and the mixture was shaken for 5 minutes with occasional venting. The aqueous layer was discarded and the organic layer was left inside. About 25.0ml of 10% NaOH was then added and the mixture was shaken as before. The aqueous layer was collected and then cooled in an ice bath. It was then acidified with enough 6.00 M HCl while the pH is being monitored with red litmus paper. Another 25.0 ml of hexane was added and the mixture was shaken as before. The hexane extract was saved and a small amount of anhydrous sodium sulfate was added. The mixture was then swirled for a couple of minutes then filtered. A small amount of the final extracted was tested separately with 1% FeCl3 and Bayer’s reagent.
The purpose of this experiment is to compare the processes of distillation and fractional distillation to discover which procedure enables a more pure sample of ethanol to be collected from an ethanol/water mixture.