Introduction
Friedel-Crafts acylation of anisole with acetic anhydride was used in this experiement to synthesize 4-methoxyacetophenone with the use of a reflux apparatus. Friedel-Crafts reactions can be done by alkylation, which involves mixing an alkyl or acyl halide with a Lewis acid, or acylation, which is done with acid chlorides or anhydrides(Lefevre). Acylation was used because it does not have as many disadvantages aklyations reactions have such as polyalkylation, second electrophilic attacks, and the rearrangement of alkyl carbocation electrophile (McMurry). Acylation reactions require molar amounts of a Lewis catalyst, in our case Aluminum Chloride (AlCl 3) was used (Arata, Nakamura, & Shouji).
Materials and Methods
Reflux
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This was done for 15 minutes until there were no visible vapors coming from the reaction mixture. The reaction mixture was then poured into a 50-mL beaker containing 5g of ice. The reaction flask was rinsed three times with 2 mL of dichloromethane. The rinsing was also added to the ice mixture.
The mixture was transferred to a seperatory funnel. Sodium Hydroxide (NaOH, 1 mL) was added to the funnel and the funnel was shaken vigorously making sure to open one end periodically to allow air to escape. The layers were allowed to separate and the two layers were poured into two separate beakers. The organic layer was poured back into the funnel and this step was repeated once more with NaOH, then again with NaCl. Once the organic layer was separated, 520g of anhydrous Magnesium Sulfate was added to dry the layer.
Distilling and Crystallizing the Product The organic layer was heated for approximately 30 minutes on a hot plate to try and remove the dichloromethane. Petroleum ether (1 mL) was added to a test tube and placed in an ice bath. The product from the flask was transferred to a watch glass. The 1 mL of petroleum ether was used to wash the crystals on the watch glass and was removed using a pipet.
Results
With the methods used, .053g of 4-Methoxyacetophenone was obtained.
Discussion
The theoretical yield of 4-Methoxyacetophenone is .764g. Our actual experimental yield was .053g. The percent yield was 6.9%.
The crude product was washed by taking the reaction product in the separatory funnel and adding 23 mL of deionized H2O. The mixture was shaken and allowed to settle until layers were observable. The top layer was the desired product and approximately 25 mL of aqueous layer was extracted from the separatory funnel. Next, 25 mL of 5% NaHCO3 was added to the separatory funnel in order to neutralize the acid. This mixture was swirled, plugged with the stopper and inverted. Built-up gas was released by turning the stopcock to its opened and closed positions, releasing CO2 by-product. This was done four times in one minute intervals. The solution was allowed to settle until layers were observable. The bottom layer that contained salt, base and water was extracted from the separatory funnel. The crude product was washed again as mentioned previously.
24) Separate the formed crystals (benzoin) and allow them to dry, then take the MP.
The next day an orange goopy textured product resulted. The extracts were then dried and combined with anhydrous sodium sulfate, then evaporated with dry air under the hood in a warm water bath. The liquid was cooled and had an initial weighing of 0.5887g. It was reweighed several minutes later with a final
What was concluded when doing the lab was to determine which product of the equation was the limiting reactant. When doing all the calculations were 83.1% of the yield of the compound. It is very close to having almost the perfect percentage of the limiting yield when doing the
Wash (swirl and shake) the organic layer with one 10-mL portion of water and again drain the lower aqueous layer. Transfer the organic layer to a small, dry Erlenmeyer flask by pouring it from the top of the separatory funnel. Dry the crude t-pentyl chloride over 1.01 g of anhydrous calcium chloride until it is clear (see Technique 12, Section 12.9). Swirl the alkyl halide with the drying agent to aid the drying.
The mixture was heated at 120°C using an aluminum block and was stirred gently. After all of the solid dissolved, it was heated for 20 additional minutes to ensure the reaction was complete.
After dissolving benzoic acid in 1.0mL CH2Cl2 and 1.0mL 10% NaHCO3 solution, two layers are created, the top layer is 10% NaHCO3 solution and the bottom is CH2Cl2.
As the acid was being added, the mixture was being stirred over a stir plate. Once completed, the reaction mixture was poured from the round bottom flask into a 500 mL separatory funnel and its top (organic) layer was extracted into another beaker. The bottom (aqueous) layer was placed back into the funnel and extracted twice with 50.0 mL of ethyl ether each. The newly extracted layers were combined and dried over magnesium sulfate (MgSO4). The dried solution was the decanted into a beaker to remove the MgSO4 salts and the product solution was collected via Buchner vacuum filtration. The resulting product was transferred into an Erlenmeyer flask with an inverted beaker on top and stored in a drawer.
The purpose of this lab was to synthesize triphenylmethanol from benzophenone and bromobenzene by the formation of a Grignard compound with the reagents bromobenzene and magnesium metal. The bromobenzene was first transformed into the Grignard compound and was then reacted with the benzophenone to make the final product. The mixture was then mixed with sulfuric acid and the organic layer was extracted via a separatory funnel. The mixture was then recrystallized from methanol and was allowed to dry and the percent yield, melting point, and the IR was obtained. The mass of the product obtained was 5.45 grams and the percentage yield was determined to be 41.95%. The melting point range obtained from the final product was 89-91°C
Different procedures were used to isolate benzil from the ether layer and benzoic acid from the aqueous layers. To isolate benzil, anhydrous MgSO4 was added to the flask containing the ether layer solution. MgSO4 removes the remaining water in the ether layer solution. After making sure that enough amount of MgSO4 present in the solution, the ether solution was filtered by using gravity filtration. During filtration, MgSO4 was removed from the solution and the ether solution was collected in 25 ml flask. To separate benzil from the filtered ether solution, the beaker containing the ether solution was heated until the ether evaporated. After letting the beaker to cool to room temperature, the mass of the beaker with the benzil crystals was measured. From the combined mass of the beaker and the benzil crystals and from the predetermined mass of the beaker, the mass of the collected crystals was calculated to be 0.266 gram.
In this preparative lab, an aldol (trans-p-anisalacetophenone) was produced from the reaction between p-anisaldehyde and acetophenone with the presence sodium hydroxide. The reaction also showed the importance of an enolate and the role it played in the mechanism. Sodium hydroxide acts as a catalyst in this experiment and is chosen because of its basic conditions and pH. The acetophenone carries an alpha hydrogen that has a pKa between 18 and 20. This alpha hydrogen is acidic because of its location near the carbonyl on acetophenone. When the sodium hydroxide is added, it deprotonates the hydrogen and creates an enolate ion. This deprotonation creates a nucleophilic carbon that can attack an electrophilic carbon (like a parent
The mixture was cooled down to room temperature and transferred to a separatory funnel where it was washed with four portions of 50 mL of water.
This process was then repeated two more times with subsequent additions of 10 mL of the 0.5M aqueous NaHCO3 and the aqueous layers drained off into the above mention labeled 100-mL beaker. Finally 5 mL of deionized water was placed into the funnel and mixed. The water was then drained off into the beaker containing the aqueous solution extracts. The solution was then saved until need later in the experiment.
A 0.5 g of sodium tungstate dihydrate was weighed and transferred into a 50-mL round-bottom flask with a magnetic stir bar. Approximately 0.6mL of Aliquat 336 was then transferred carefully into the round bottom flask using a 1mL syringe. The round bottom flask and its contents were then set up in an oil bath. 11mL of 30% hydrogen peroxide and 0.37 g of potassium bisulphate were added to the reaction mixture in the round bottom flask and stirred using a magnetic stirrer. Lastly, 2.5mL of cyclohexene was added using automatic dispenser and the mixture stirred. A condenser was fitted on the round bottom flask, clamped and attached to water horses. The reaction mixture was then heated on the oil bath and the reflux process initiated for an hour while stirring the mixture vigorously. Half way while rinsing, any trapped cyclohexene in the condenser was rinsed. After 1 hour, the round bottom flask was rinsed
4-boromo aniline failed in this reaction because of reduced solubility of its corresponding imines due to molecular weights increases. Although, in most cases, aldehyde derivatives did not constitute the product with acceptable yield, almost all the amines underwent smooth reactions to produce their derivatives in good to excellent yields at room