Pre Lab 2 - Conversion of Carvone to carvacrol PDF

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Conversion of Carvone to carvacrol...

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Conversion of acid-catalyzed isomerization of Carvone to Carvacrol Introduction: The experiment will focus on the acid-catalyzed isomerization of (R)-carvone to Carvacrol. This isomerization converts an active compound into an inactive product. A combination of reflux. liquid/liquid extraction, suction filtration, IR, and NMR spectroscopy will be used to perform and achieve the results. This reaction will happen under the acidic conditions with sulfuric acid and heat. A carbocation rearrangement coupled with a keto/enol tautomerization will occur in the formation of carvacrol form (R)-(-) carvone. First, reflux will be used to react (R)-(-) carvone with sulfuric acid under heat. The purpose of reflux is to ensure that constant heat is applied to the chemical reaction without losing any liquid to evaporation. Later, liquid/liquid extraction will be used to obtain and isolate the product. Suction filtration is used to remove the drying agent sodium sulfate from the solution. Finally, an IR and NMR spectroscopy will be performed to ensure the reaction of (R)-(-) carvone to carvacrol. Balanced Equation:

Mechanisms:

Table of Reagents Compound Name

structure

BP (°C)

(R)-(-)carvone

MW (g/mol) 150.22

MP (°C)

Density (g/mL)

25.2 °C

0.959

Carvacrol

150.22

234 °C

1 °C

0.976

Sulfuric acid

98.08

270 °C

1.84

Diethyl ether

74.12

35 °C

0.71

Sodium bicarbonate

84.006

50 °C

2.2

Sodium sulfate

142.04

884 °C

2.66

water

18.02

Brine (sodium chloride/water)

76.46

100 °C

1 -25 °C

1.186

Safety: ● Safety glasses, lab gloves, and lab coats must be worn at all times. ● Brine is not flammable but may be irritating to the respiratory tract, eyes, and skin.

● (R)-(-) carvone is not very flammable; however, is harmful when swallowed. In addition, it also harmful to the respiratory system when inhaled. ● Carvacrol will cause irritation when it is contacted to the skin, it can also be harmful when is being inhaled. It is also slightly flammable. ● Sulfuric acid is not flammable. It will cause irritation when it is contacted to the skin, be in severe pain when in contact with the eye, and is harmful to the respiratory system. ● Diethyl ether is flammable. It can cause irritation when in contact with the skin and the eye. ● Sodium bicarbonate is not flammable; however, preventing dusting into the eye. ● Sodium sulfate is not flammable; however, may cause skin and eye irritation. If ingested can cause nausea, vomiting, and diarrhea. Procedure 1. Prepare 2.0 g of R-(-) carvone to a 100 mL round bottom flask and prepare a magnetic sit bar into the round bottom flask. 2. Add 25 mL of 6M sulfuric acid and reflux the solution for 45 minutes. 3. Remove the solution from heat, and stir the solution to cool down for 10 minutes. 4. Prepare an ice bath while the solution if cooling. 5. Put the solution into the ice bath for 10 minutes. 6. Transfer the reaction mixture to a separatory funnel, and extracted twice with 25 mL of diethyl ether. 7. Wash the combined organic layer with 15 mL of water and then washed with 15 mL of saturated NaHCO3. 8. Then wash the organic layer with 15 mL of brine and dry the solution by using sodium sulfate. 9. Remove the drying agent by vacuum filtration and transfer the product to a 24/40 round bottom flask. 10. Record the mass of the produce, and conduct IR and NMR of the crude product....