Friedel – Crafts Acylation: Synthesis of 4-Methoxyacetophenone

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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 …show more content…

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.

With the methods used, .053g of 4-Methoxyacetophenone was obtained.

The theoretical yield of 4-Methoxyacetophenone is .764g. Our actual experimental yield was .053g. The percent yield was 6.9%.

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