VII] FATS AND ALLIED SUBSTANCES 97 



Palm wax is obtained from the stem of the Wax Palm (Ceroxylon 

 andicolum), a native of the Andes, and Raphia wax from the leaves of 

 another palm {Raphia Ruffia). Pisang wax is produced by the leaves of 

 a variety of the Banana {Musa Cera). 



Waxes from different plants contain mixtures of various esters, of 

 which the component alcohols have been mentioned above. The most 

 commonly occurring acids are myristic, lignoceric, carnatibic, cerotic and 

 melissic acids (see p. 89). 



Expt. 96. Tests for wax. Take some commercial carnaiiba wax and make the 

 following experiments : 



(a) Warm a small piece with alcohol in a test-tube. It goes into solution and 

 separates out on cooling as a white crystalline deposit. Examine the crystals under 

 the microscope. 



(6) Warm a small piece with ether. It is soluble. 



(c) Heat a small piece of wax with solid potassium hydrogen sulphate in a test- 

 tube. There is no smell of acrolein, since glycerol is absent [see Expt. 92 (c)]. 



Phytosterols or Plant Sterols. 



These substances are unsaturated monohydric alcohols of high 

 molecular weight of which the structural formulae are unknown. They 

 are probably present in all parts of plants but the members most fully 

 investigated have chiefly been obtained from seeds. The sterols are 

 always found accompanying vegetable fats, and this connection is ac- 

 centuated by the fact that they are soluble in the solvents used in fat 

 extraction. When the fat is saponified, the sterols remain unaltered and 

 are said to form the "unsaponifiable residue" of fats. 



Various sterols have been isolated from different plants: many are 

 isomeric and a usual formula is C27H45OH. One of the best defined 

 sterols is sitosterol which occurs in the grain of the Wheat {Triticum 

 vulgare) and Rye (Secale cereale): also in seeds of the Flax (Linum 

 usitatissimum) and the Calabar Bean {Physostigma venenosum). 



Expt. 97. Detection of sterol in the grain of the Wheat. Weigh out 300 gms. of 

 grains and grind them in a coffee mill. Add 350 c.c. of ether to the ground mass in 

 a flask, and allow it to stand for 24 hrs. Filter the extract through a pad of asbestos 

 or glass wool in a funnel. Then wash the residue with another 150 c.c. of ether and 

 filter. The ether extract is then saponified with sodium ethylate which is prepared 

 as follows. Weigh out 2 gms. of metallic sodium, cut it into small pieces and add it 

 slowly to 20 c.c. of 96-98% alcohol. When it has dissolved, add the solution of 

 sodium ethylate to the ether extract in a separating funnel, shake well and allow the 

 mixture to stand for at least 24 hours. Saponification takes place in the cold, and 

 soap separates out. Filter, and shake up the filtrate several times with water in a 

 o. 7 



