Experimental Procedure Part A: Isolation of Clove Oil
1) Weigh 5 g of dry cloves. Grind them to a coarse powder using a mortar and pestle. Reweigh the powder and record the weight. 2) Transfer the ground cloves to a 100 mL round‐bottom flask. Add 50 mL of distilled water and a few boiling chips. 3) Assemble the distillation apparatus (Figure 2). Use the 100 mL round‐bottom flask as the pot and 50 mL graduated cylinder or Erlenmeyer flask as the receiver. Start the flow of water through the condenser. Figure 2 Distillation set up 4) Ask your instructor to inspect your equipment set up. Turn on the heating mantle. When the mixture boils, adjust the heat to maintain a distillation rate of approximately 1 drop per second . 5) Stop the distillation when approximately 30‐40 mL of distillate has been collected. 6) Allow the distillate to cool to room temperature. Carefully pour the distillate into a separatory funnel. Add 10 mL of saturated NaCl solution. 7) Rinse the inside of the condenser and the receiver with 5‐10 mL of CH2Cl2 into the separatory funnel. 8) Cap the separatory funnel and gently swirl the contents for several seconds. Vent the separatory funnel frequently. After the pressure has been vented, shake the contents vigorously to thoroughly mix the two layers. 9) Allow the layers to separate. Drain the CH2Cl2 layer into an Erlenmeyer flask. 10) Repeat the extraction of the aqueous layer twice, each time with 5 mL portion of CH2Cl2. Combine organic layer in the same Erlenmeyer flask. 11) Dry the combined CH2Cl2 solution with anhydrous Na2SO4. 12) Decant the CH2Cl2 solution into a pre‐weighed ceramic evaporating dish, making certain that no Na2SO4 is transferred with the solution. 13) Place the evaporating dish on a hot water bath to remove CH2Cl2. 14) When all of the CH2Cl2 has been evaporated, allow the evaporating dish to cool to room temperature. Weigh it to the nearest 0.001 g and record the weight. Subtract the mass of the empty dish to obtain the mass of the clove oil. 15) Report the weight and percent yield of clove oil to your instructor. Part B: Characterization of the Isolated Clove Oil 1) Dissolve the clove oil in 2‐3 mL of methanol. 2) Obtain six test tubes and label them 1‐6. Label tubes 2, 4, and 6 as “blank”. Add 1 mL of methanol to all 6 test tubes. 3) Add 5 drops of clove‐oil solution to tubes 1, 3, and 5. Gently swirl each tube. 4) Add 5 drops of bromine in chloroform to tubes 1 and 2. Gently swirl and record your observation. 5) Add 5 drops of KMnO4 solution to test tubes 3 and 4. Gently swirl and record your observation. 6) Add a few drops of FeCl3 solution to test tubes 5 and 6. Gently swirl and record your observation. Laboratory Safety Precaution 1) Wear safety goggles and lab coat at all times while working in the laboratory. 2) Dichloromethane is irritating and toxic. Prevent eye, skin, and clothing contact. 3) Anhydrous sodium sulfate is irritating and hygroscopic. ‐ 53