6 FATS, OILS, AND WAXES 



C 2 H 5 OH + H 2 SO 4 = C 2 H 5 HSO 4 + H 2 O 

 Ethyl hydro- 

 gen sulphate 



C 2 H 5 OH + CH 3 COOH = CH 3 COOC 2 H 5 + H 2 O 

 Ethyl Acetic Ethyl acetate 



alcohol acid 



The reaction between an acid and an alcohol containing 

 three hydroxyl groups (OH) instead of only one, may be 

 expressed by the following equation : 



CH 2 OH C^HggCOOH C^H^COOCH,, 

 CHOH + C 17 H 35 COOH = C^HggCOOCH + 3H 2 O 



CH 2 OH C 17 H 35 COOH C 17 H 35 COOCH 2 

 Glycerol Stearic acid Tristearyl glycerol 

 or tristearin 



the resulting compound tristearin also being an ester. 



The naturally occurring fats are mixtures of similar esters 

 of glycerol with other fatty acids such as palmitic C 15 H 31 COOH 

 or butyric C 3 H 7 COOH acids, or with the unsaturated acid 

 oleic acid C 17 H 33 COOH. 



A wax, on the other hand, is an ester of a monohydric 

 alcohol as illustrated by the equation : 



C 15 H 31 COOH + C 30 H 61 OH = C 15 H 31 COOC 30 H 61 + H 2 O 

 Palmitic acid Myricyl Myricyl palmitate 

 alcohol 



myricyl palmitate being the chief constituent of beeswax. 



Lapworth and Pearson * have shown that the glycerol in 

 fats may be directly replaced by a higher polyhydric alcohol 

 such as mannitol. This replacement may be brought about 

 by distilling olein or stearin with mannitol under reduced 

 pressure in the presence of sodium ethoxide. By this treat- 

 ment much of the glycerol of the fat is expelled, the maximum 

 yield being reached when the proportion of fat to the mannitol 

 corresponds with two molecules of the former to three mole- 

 cules of the latter. The composition of the mannitol olein, 

 or mannitol stearin, corresponds with that of a mixture of 

 dioleates or distearates of mannitan and isomannide. It has 

 been shown by feeding experiments that mannitol olein is 

 utilized by animals to the same extent as olive oil.f 



* Lapworth and Pearson : " Biochem. Journ.," 1919, 13, 296. 

 f Halliburton, Drummond and Cannan : id., 1919, 13, 301. 



