The extraction and recrystallization will be completed during the first lab week for Project 1. The Product Analysis will be accomplished during the second week.
Extraction of Crude Trimyristin
1. In a 100 mL round bottom flask, mix ~5 g nutmeg and 50 mL 1:1 anhydrous ethanol:ethyl acetate.
2. Add a magnetic stir bar to the flask and stir the mixture while refluxing for 45 minutes. (During this time, complete step 1 under Recrystallization of Trimyristin).
3. After the refluxing period, vacuum filter the warm solution to remove the nutmeg.
4. Transfer the extraction solution to a clean round bottom flask and remove the solvent by rotary evaporation. (Your instructor/TA will help you with the equipment).
5. Isolate the crude solid by vacuum filtration: Use a small amount of cold ethanol to transfer the resulting solid from the round bottom flask into a Buchner funnel. Allow the suction to briefly dry the solid.
Recrystallization of Trimyristin
1. Determine the best choice of solvent for recrystallizing trimyristin:
a. Use a 250 mL beaker to prepare a boiling water bath on a hot plate.
b. Place a half-pea-sized amount of solid trimyristin in each of 4 test tubes.
c. In each test tube, add ~2 mL of one of the solvents to be tested (water, ethyl acetate, acetone, and ethanol).
d. If the solid does not dissolve, heat the test tube in the water bath to determine if it is soluble at higher temperature. (You may add a little additional solvent if the trimyristin appears to partially dissolve).
e. For any samples that display solubility at higher temperature, cool the test tube in an ice bath to see whether the dissolved trimyristin recrystallizes.
f. Use your results to determine the best solvent for recrystallizing trimyristin.
2. Recrystallize your entire sample of crude trimyristin using the sample you chose in Step 1.
a. Add the solid sample to a 50 mL Erlenmeyer flask.
b. Add enough HOT solvent to cover the solids.
c. Place the flask on a warm hot plate and add solvent in small increments until all of the solid dissolves.
d. Allow the solution to cool SLOWLY to room temperature.
e. When the mixture is room temperature AND solids have reappeared, chill the flask in an ice bath. Separately chill some of the recrystallization solvent as well.
f. Vacuum filter the chilled solids, washing them with a small amount of the cold solvent.
g. Allow the solids to dry with the vacuum running for at least 20 minutes.
3. Save your recrystallized trimyristin in an uncapped test tube for analysis the following week.
Product Analysis (Week 2)
1. Determine the melting point of two samples: 1) your isolated trimyristin and 2) a mixture of your sample with a trimyristin standard. NOTE: There are three sample slots in the Digimelt apparatus, so these samples may be run simulataneously. Look up the melting point of trimyristin. Start your melting point analysis at a temperature ~15°C lower, and use a ramp rate of 2°C per minute.
2. Obtain an infrared spectrum of your trimyristin. (Your instructor and/or TA will show you how to use the instrument).
3. Determine the mass of your trimyristin and save it in a capped test tube for Project 2.