Intramolecular Friedel-Craft Acylation PDF

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Summary

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Description

Melina Rosado 2/14/18 Experiment: Intramolecular Friedel-Crafts Acylation The purpose of this lab experiment is to understand intramolecular Friedel-Crafts Acylation by forming α-tetralone using 4-phenylbutyric acid. Mechanism

Compound

Molecular weight (g/mol)

Density (g/mL)

Boiling point °C

Melting Point °C

Amount used

Methanesulfonic acid α-tetralone

64.05

1.48

167-168

20

1.5 mL

146.19

1.10

127

5-6

N/A

4-phenylbutyric

164.20

5.3 g/L

165

49-51

220 mg

acid Diethyl ether NaHCO3

74.12 84.01

713 kg/m³ 2.16

34.6 851

-116.3 50

3 mL 2 mL

Silica Ether Sodiun sulfate

60.09 74.12 142.04

2.65 713 kg/m³ 2.66

2230 34.6 1429

1600 -116.3 884

N/A 2-3 mL N/A

Structures

Melina Rosado

1.

4-phenylbutyric acid

2.

α-tetralone

3.

Diethyl ether

4.

Methanesulfonic acid

5.

Sodium bicarbonate

MSDS 

Methanesulfonic Acid: Extremely hazardous, skin and eye irritant, corrosive; skin inflammation and burning, eye redness, itching, and watering.



Sodium sulfate: irritant of skin and eye, hazardous inhalation.



4-phenylbutyric Acid: irritant of skin and eyes.



Diethyl ether: flammable, irritant of skin and eyes.



Sodium Bicarbonate: eye and skin irritant.



Silica: hazardous inhalation.



α-tetralone: toxic if inhaled, harmful if swallowed.

Procedure 1. Add 1.5 mL of methanesulfonic acid to a 5-mL conical vial equipped with spin vane and condenser. 2. Stir and heat to 85–100 ºC. 3. Once 85 °C is reached add 220 mg of 4-phenylbutyric acid and stir at reflux for one hour. 4. After one hour add the reaction mixture to a test tube that contains 5.0 mL of ice cold water.

Melina Rosado 5. Wash the aqueous layer with 3 mL of diethyl ether twice while combining both organic washed. 6. Wash the combined organic layers were with 2 mL of saturated aqueous NaHCO3 and then with 2 mL of water. 7. After water wash dry organic layer with sodium sulfate. 8. Set up a column containing cotton, a one-half inch layer of silica gel topped by a one-half inch layer of sodium sulfate and sand. 9. Isolate the product by passing the organic layer through the pipet with 5 mL of diethyl ether. 10. Rinse the pipet with an additional 2–3 mL of ether. 11. Remove the solvent under vacuum. The product is a colorless oil. 12. Obtain mass and NMR. Setup

Calculations

Melina Rosado Mass of 4-phenylbutyric aid: 0.228 g Mass of petri dish: 95.865 g Mass of petri dish and product: 95.9048 g Mass of product: 0.0398 g 1mol ∏ ¿=0.203 g of product ∏ ¿ × 146.19 g 1 mol ¿ 1 mol 1 mol ׿ 0.228 g 4− phenyl… × 164.20 g Percent yield 0.0398 g ×100=¿ 19.6% 0.203 g Conclusion/ Discussion For this lab experiment an intramolecular Fridel-Craft Acylation reaction was conducted to convert 4-phenylbutyric acid to α-tetralone. The reaction was set to reflux for 50 minutes. By the end of the reaction, the solution was a dark brown which could indicate some unreacted starting material. The solution was washed and separated into organic and aqueous layer. A column chromatography was performed to separate product from the organic layer. The product looked a little bit dark when it should’ve been a colorless oil and this could be due to impurities or contamination. The percent yield for this reaction was 19.6%. An NMR was taken for this product. HA is around 8.2 ppm which is an aromatic proton and it’s more downfield because its closer to the carbon double bond. Around 7.5 ppm HA’-HA’’’ are the aromatic protons. There is a high peak around 7.2 ppm which can indicate the solvent, in this case chloroform. HB is around 3.0 ppm and is more downfield than the other hydrogens in cyclohexanone because is next to an aromatic ring. HD is around 2.7 ppm and Hc around 2.0 ppm, and next to this peak there’s a high peak indicating water. In addition, the NMR shows TMS AT 0.00 ppm. For the IR of 4-phenylbuyric acid sp2 C-H stretch is shown around 30103100 cm-1, OH stretch around 3200-3600 cm-1, sp3 C-H stretch around 2850-3000 cm-1, aromatic carbons are shown 1600-1500 cm-1 and carbon double bond at 1650-1800 cm-1....