Isolation of Trimyristin from Nutmeg, And
1
Isolation of A Lipid from Nutmeg
Introduction
The lipids isolated from most sources contain mixtures of fatty acid components. The lipid isolated from nutmeg, however, contains almost totally the 14-carbon fatty acid, tetradecanoic acid, which is commonly called myristic acid. The lipid is commonly called trimyristin, since it is made from three myristic acids.
Chemical Equation
Precautions
Methyl t-butyl ether (MTBE) is flammable, so no flames in the lab.
Procedure
Weigh about 1.0 grams of ground nutmeg (record what use actually weigh out), and transfer it to your 25 mL round-bottomed flask. Add 10 mL of MTBE and 2 boiling stones to the flask, attach a reflux condenser, and heat the nutmeg at reflux for at least 30 minutes. Allow the reaction to cool, and filter off the nutmeg residue by gravity filtration into a 50 mL round-bottomed flask. Rinse your 25 mL round-bottomed flask with 10 ML of MTBE, and filter this into the 50 mL flask as well. Remove the MTBE on the rotary evaporator. Add 5 mL of 95% ethanol to the round-bottom flask, and heat it to boiling on the steam bath. If all of the solid doesn’t dissolve, add another 5 mL of 95% ethanol, and heat it to boiling. Once all of the solid has dissolved, remove the flask from the steam bath, allow it to cool to close to room temperature, then cool it in ice. Cool 5 mL of 95% ethanol in ice as well. Collect the solid by suction filtration using your Hirsch funnel, rinse the flask with your cold ethanol, and wash the solid in the funnel with this rinse. Transfer the solid to a watch glass, and allow it to dry for a few days. Weigh it and record its melting point range. Transfer the product to a vial labeled as trimyristin, weight, and your names.
Report format
1. Title Page
a)A descriptive title containing 10 - 20 words.
b)Course and section numbers.
c)Dates that the experiment was performed.
d)Your name, and partner’s name, if any.
2. Data and Calculations: Show your calculations.
a)Weight of nutmeg started with.
b)Weight of trimyristin isolated.
c)Calculation of percent yield of trimyristin from nutmeg. Show your work.
d)Melting point range of trimyristin.
3. Questions
a)Find a reference that tells what percent of nutmeg is trimyristin. Report the result and the reference.
b)Write balanced chemical equations for both acid and base hydrolysis of trimyristin.
c)Trimyristin is a solid, but triolein (right) is a liquid. Explain why. More than one sentence is necessary.
d)Trimyristin and myristic acid have similar melting points. What simple chemical test could you do to tell if you had isolated myristic acid or trimyristin? Describe how you would do the test, and what you would see to tell you if you had trimyristin or myristic acid.