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Chemeketa CH 241 - Trimyristin: A Fat from Nutmeg

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Chemistry 214 Clark College Trimyristin Extraction and Saponification Experiment 2 Page 1 of 4 Trimyristin: A Fat from Nutmeg This lab was developed by Dr. Tom Goodwin at the Toad Suck Institute for Green Organic Chemistry at Hendrix College in Conway, Arkansas. (http://www.hendrix.edu/chemistry/green.htm) REFERENCES 1. “Zero Effluent Laboratory”, L. R. Corwin, R. J. Roth, T. H. Morton, Brown University 2. “Soap from Nutmeg: An Integrated Introductory Organic Chemistry Laboratory Experiment”, M. C. S. De Mattos, D. E. Nicodem, J. Chem. Educ. 2002, 79, 9495; 3. “Organic Chemistry”, 4th Ed., Brown, Foote and Iverson, Brooks/Cole Publishing, Belmont, CA, 2005. INTRODUCTION Nutmeg is the common name of the seed from female Myristica fragrans, a tree native to the Spice Islands (the Moluccas, in the East Indies, now part of Indonesia). When the fruit of the tree matures, it splits in two, exposing a single seed sheathed in a crimson aril. The aril, a fibrous covering, constitutes the spice known as mace, and the seed is a whole nutmeg. Nutmeg has been known as a spice in the Middle East for at least 2500 years, but it was not introduced into Europe until the Middle Ages. Dutch and Portuguese merchants monopolized the European nutmeg trade until 1843, when French and British interests succeeded in cultivating nutmeg trees in the West Indies. There is a decided difference between East Indian and West Indian nutmeg. Like many other spices, nutmeg has a long history of medicinal use. Preparations of nutmeg have been used as analgesics, digestive stimulants, aphrodisiacs, amenorrheal agents, and hypnotics. Medicinal use has declined since the 18th century, save for a brief period at the end of the 18th century, when it was rumored to be an effective abortifacient. Several medical journals of this period reported a high incidence of nutmeg poisoning among women. The nutmeg is about half cellulose. The other major components are fats, 25-40%, and essential oils, 8-15%. The former constitute the major portion of the expressed oil of nutmeg (obtained by distilling the seed with steam). Both of these components contain thousands of different compounds, only a handful of which have been identified. The expressed oil, also known as nutmeg butter, is composed principally of a lipid called trimyristin, the structural formula of which is illustrated in reaction 1. This fat also occurs in other plant and animal products, such as coconut oil and cow’s milk. Trimyristin is an example of fundamental type of fat known as a triglyceride. Hydrolysis of one mole of a triglyceride affords one mole of 1,2,3-propanetriol (glycerin) and 3 moles of fatty acids, which are carboxylic acids containing the functional group at the end of a long alkyl chain. In addition to trimyristin (which is odorless when pure), solvent extraction of nutmeg yields as major components the three compounds illustrated below, which are responsible for most of the characteristic nutmeg odor. Myristicin occurs in much higher concentration than elemicin or safrole. OH3C(H2C)12O O (CH2)12CH3OOH3C(H2C)12OtrimyristinH3COH3COH3COOCH3myristicinelemicinsafroleOOOOChemistry 214 Clark College Trimyristin Extraction and Saponification Experiment 2 Page 2 of 4 Myristicin has been studied pharmacologically. In mice it inhibits the action of monoamine oxidase, an important enzyme in the central nervous system, and a distinct psychotomimetic effect has been detected in man. The effect of myristicin is reported to be stronger when the other constituents of the volatile oil are present. It has been suggested that the other components do not themselves contribute to the psychotropic activity, but promote absorption of myristicin by irritating the gastrointestinal tract. One hypothesis regarding the hallucinogenic activity of allylbenzene derivatives is that they are metabolized to compounds related to amphetamine. As for many pharmacologically active substances, the difference between an effective dose and a toxic dose is not great. An after effect of ingestion of large quantities of nutmeg or myristicin is a lasting aversion to its taste or smell. PROCEDURE Extraction of Trimyristin: 1. Add 20 ml of petroleum ether to powdered nutmeg (approx.10 g, weighed to nearest 0.1 g) in a 50 ml round-bottomed flask. (Note: “petroleum ether” is an historical name, and a misnomer. This solvent is actually a mixture of low molecular weight alkanes, and not an ether at all. It has properties much like gasoline, so you should avoid flames, keep the solvent vapors away from hot surfaces, avoid inhalation, and avoid skin contact.) 2. Add a boiling stone, lightly grease the glass joint, and reflux the mixture GENTLY (keep the heat low) for 30 minutes (30 minutes of actual boiling time) under a water-cooled condenser. Record frequent observations in your notebook. 3. At the end of the reflux period, turn off the heat, and move the heating mantle away from the round-bottomed flask so that the flask can cool. Allow the flask to remain undisturbed while it cools, and the insolubles settle to the bottom. 4. When the flask is cool to the touch, pipet the liquid away from the solid. The liquid solution is what we want to keep, since it contains the extracted trimyristin. Put a small latex bulb on a short Pasteur pipet and, without disturbing the precipitate, transfer as much of the liquid as you can to a tared, clean, dry, 100 mL round-bottomed flask. NOTE: YOU MUST MINIMIZE THE TRANSFER DISTANCE FROM ONE ROUND-BOTTOMED FLASK TO ANOTHER, OR RISK LOSING SOLUTION AS IT SQUIRTS OR DRIPS FROM THE PIPET. Try to avoid getting solution on the ground glass joint of the flask. 5. Now to transfer the remaining liquid, your objective is to place the tip of the pipet on the inside bottom of the round-bottomed flask, without getting any of the brown solid into the pipet. This works best if, as you slowly plunge the tip through the liquid and solid, you slowly depress the bulb so that bubbles are slowly expelled through the tip to expel any solid that tries to enter. Once the pipet tip is seated on the flask bottom, gently expel any remaining air from the bulb, then slowly allow the bulb to inflate. If you do this carefully, the solid particles will be excluded from the pipet, and the liquid will slowly seep in. Once the latex bulb is fully inflated (i.e., no longer sucking up liquid), you need to transfer the liquid


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