Friedel- Crafts Acylation of Anisole PDF

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Friedel- Crafts Acylation of Anisole...

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Cari Hall CH 237-001 Experiment 7 April 9,2021

Friedel- Crafts Acylation of Anisole

I.

Introduction The purchasing agent at the olfactory accidentally ordered 500 kilograms of anisole instead of 500 pounds. The company needs to find a way to use the excess. The chemical technicians think it would be possible to synthesize 4- methoxyacetophenone from the anisole using Friedel- Crafts reaction. They are concerned about yielding the wrong isomers or a mixture of isomers that will be hard to separate. The goal of this experiment is to see weather or not Friedel- Crafts Acylation of Anisole yields mainly 4methoxyacetophenone or other isomers. The Friedel- crafts reaction is a form of substitution where a new carbon carbon bond is formed in place of an acyl or alkyl group. In this experiment aluminum trichloride reacts with acetic anhydride to form an acylium ion. In the next steps the acylium ion will react with the aromatic ring of anisole to form 4- methoxyacetophenone

II.

Results The theoretical yield of acetylanisole is calculated by following the steps below: -

(mass of anisole)/ (molar mass of anisole) * (1 mol of product/ 1 mol anisole * molar mass of methoxyacetophenone)

-

(1.08g/ 108.2 g/mol)*( 1/1 *( 150.2 g/mol)= 1.505 g

Cari Hall CH 237-001 Experiment 7 April 9,2021

The percent yield is calculated as follows: -

( Mass of recovered product)/ ( theoretical yield) *100

-

0.805g/ 1.505g * 100= 53/4%

During distillation the boiling range of the product starts at 172 degrees celsius through 178 degrees celsius.

According to the NMR the ortho isomer had 6 peaks: -

2 singlets with integration of 3 hydrogens

-

2 doublets with integration of 1 hydrogen

-

2 triplets with integration of 1 hydrogen

According to the NMR the meta isomer had 6 peaks: -

2 singlets with integration of 3 hydrogens

-

1 singlet with integration of 1 hydrogen

-

2 doublets with integration of 1 hydrogen

-

1 triplet with integration of 1 hydrogen

According to the NMR the para isomer had 4 peaks: -

2 singlets with integration of 3 hydrogens

Cari Hall CH 237-001 Experiment 7 April 9,2021 -

2 doublets with integration of 2 hydrogen

After analyzing the spectrum it can be confirmed that para-methoxyacetophenone is the only isomer formed. The NMR spectrum shows four peaks, two doublets and two singlets. The singlet occurring at 2.5 ppm corresponds to the three hydrogens of the methoxy group. The other singlet is in relation to the three hydrogens of the acetyl group. The doublet occurring at 6.9 ppm corresponds to the two equivalent aromatic hydrogens closest to the methoxy group. The other doublet occurs at 7.9 ppm and corresponds to the two equivalent aromatic hydrogens closest to the acetyl group. The para-isomer is the only one of the three that is symmetrical, which results in equivalent hydrogens and is why we only observe four peaks in the spectra instead of six, like the meta- and ortho-isomers. The asymmetrical isomers can be excluded as possible products.

III.

Discussion This particular experiment generally produced a low yield. So in order to try and

remedy that washing the aluminum trichloride with DCM helped produce a larger yield. After attaching the reflux condenser to the reaction flask the solution turned a deep purple in color. After washing it with crushed ice I made the mistake of not waiting for the solution to change to

Cari Hall CH 237-001 Experiment 7 April 9,2021 a grey- green color. In order to reverse this I added extra DCM before beginning the separation process.

IV.

Conclusion The goal of this experiment was to see weather or not Friedel- Crafts Acylation of

Anisole yields mainly 4- methoxyacetophenone or other isomers. According to the NMR it can be concluded that the para isomer is formed. Using this new information the chemical technicians at the Olfactory can make an informed decision on how to use the excess.

Cari Hall CH 237-001 Experiment 7 April 9,2021

Cari Hall CH 237-001 Experiment 7 April 9,2021

Cari Hall CH 237-001 Experiment 7 April 9,2021

Cari Hall CH 237-001 Experiment 7 April 9,2021

Cari Hall CH 237-001 Experiment 7 April 9,2021

Cari Hall CH 237-001 Experiment 7 April 9,2021...