Trimyristin from Nutmeg

Purpose To apply the technique of extraction for isolating a natural product. 

Diethyl ether and acetone are both highly volatile and flammable solvents. Use no flames or electrical dryers in the laboratory during this experiment. 

Monitor the heating of diethyl ether under reflux so that the ring of condensate remains in the lower third of the condenser. This will ensure that no vapors escape from the condenser into the room. Very little heat will be required regardless of the heating source used to maintain reflux. 

Preparation Sign in at www.cengage.com/login to answer Pre-Lab Exercises, access videos, and read the MSDSs for the chemicals used or produced in this procedure. Read or review Sections 2.7, 2.9, 2.10, 2.11, 2.13, 2.17, 2.21,2.22, 2.29, 3.2, and 3.3. 

Apparatus A 25- and a 50-mL round-bottom flask, ice-water bath, apparatus for heating under reflux, magnetic stirring, simple distillation, vacuum filtration, and flameless heating. 

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In one of the experiments in this chapter, you isolate the naturally occurring fat trimyristin from nutmeg, a valuable spice. In other experiments in this textbook, you have the opportunity to isolate citral, the odoriferous component of lemongrass oil (Sec. 4.6), and to separate different pigments found in green leaves (Sec. 6.2). You may also examine the two enantiomers of carvone, one of which is found in spearmint and the other in caraway seed oil (Sec. 7.4). The techniques you will use in these experiments serve as an introduction to the methods that are used in research laboratories to isolate natural products having potential value to society. 

Microscale extractions of trimyristin from nutmeg, and cholesterol from gallstones, have been described. Diethyl ether was used as the solvent in both cases. A packed Fhsteur pipet column was used for filtering, drying (nutmeg experiment), and decolorizing (gallstone experiment). 

Myristic acid occurs as a glyceride in many vegetable fats and oils, in particular in coconut oil,i its isolation from which involves separation from homologs by fractional distillation of the acids or their esters. The trimyristin obtained from nutmegs 2 (p. 100) or from the seeds of Virola venezuelensis forms the most suitable source. 

The only convenient source of trimyristin is nutmegs, and ether is the most suitable solvent for its extraction. It has also been prepared from glycerol and myristic acid. ... 

Trimyristin is a white crystalline fat, m.p. 54-55 , obtainable from nutmeg, and is the principal constituent of nutmeg butter. Hydrolysis of trimyristin with hot aqueous sodium hydroxide gives an excellent yield of myristic acid, m.p. 52-53 , as the only fatty acid. 

So here is the major justification for the equation between the essential oils and the Essential Amphetamines. Care must be taken to make an exact distinction between myristicin (this essential oil) and myristin (the fat) which is really trimyristin or glyceryl trimyristate from nutmeg and coconut. This is the fat from myristic acid, the C-14 fatty acid, and these two similar names are often interchanged even in the scientific literature. 

Extraction of natural materials often produces complex mixtures of products, as described in the Historical Highlight at the end of this chapter, so additional operations are required to separate and purify individual compoimds. These procedures may involve techniques in which the compounds are separated on the basis of their acidic or basic properties (Sec. 5.3) or by chromatographic methods (Chap. 6). Thus, the isolation of pure natural products normally involves a series of complex and time-consuming operations. Fortunately there are some exceptions to this general rule. The isolation of trimyristin (20) from nutmeg is one of them. 

Considering the solubility properties of trimyristin (20), would water be a good choice as an extracting solvent for obtaining 20 from nutmeg ... 

If nutmeg butter, a commercial fat obtained by the hot pressing of ground nutmegs, is available, the above extraction may be omitted. The only operation necessary is a double crystallization of the crude material from boiling 95 per cent alcohol. Since nutmeg butter is frequently adulterated with foreign fats, the purity of the product should be checked by the saponification number (232 for pure trimyristin). 

The filtrate from the crude trimyristin contains the odorous oils of the nutmeg. A further quantity of trimyristin may be obtained from it by distilling with steam and recrystallizing the non-volatile residue twice from alcohol but the amount is not commensurate with the trouble, and this operation is not advised unless the residues from at least 5000 g. of nutmegs are on hand. 

The compound trimyristin, 5.19, can, unusually, be isolated from ground nutmeg by ether extraction (its concentration and solubility are high). It is purified by recrystallization from acetone ... 

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