CHFiMTCVL PROPERTIES OF FATS AND OILS 277 



the large proportion of the hydroxyl-containing triglyceride triricinolein, 

 this fat reacts rapidlj^ with alcohols. ^^- A methaiiolysis of coconut oil in the 

 presence of hydrochloric acid has been used by Elsdon*^^ for the estimation 

 of the component acids. 



(a) Glyceroli/sis. A special type of alcoholysis is exemplified by the re- 

 action between the triatomic alcohol glycerol, and fat. This reaction is 

 widely employed commercially for the production of partially esterified 

 products. 



According to Marklej^,^^* several different reactions are possible be- 

 tween glycerol and triglyceride molecules. According to these schemes, 

 one mole of triglyceride can react with V2, 1, or 2 moles of glycerol to 

 jjroduce var^ying proportions of either mono- or diglycerides or both. These 

 reactions are illustrated below: 



HzC-O-C-R HOCHj HaCOH HjCOH 



HC-O-C-R + HOCH ► HC-O-C-R + HCOH 



HzC-G-C-R H0CH2 HaC-O-C-R HzCOC-R 



Triglyceride Glynerol Diglyceride Monoglyceride 



HaC-O-C-R HOCH2 HjCOH 



^0 I I 



HC-O-C-R + 2 HOCH «.3 HCOH 



HaC-O-C-R HOCH2 H2C-O-C-R 



Triglyceride 2 Glycerol .3 Monogl\ceride 



J" 

 HzC-G-C-R HOCHa H2COH 



10 1 10 



2 HC-O-C-R + HOCH -Z HC-O-C-R 



I /O I I /° 



H2C-0-C-R HOCH2 H2C-0-C-R 



2 Trigl\'ceride Gl\cerol 3 Digl.\-ceride 



Eckey and Formo-* have recently described a procedure for the syntheses 

 of mono- and diglycerides in which the so-called "directed" interesterifica- 

 tion is employed. Previously dried c.p. glycerol is mixed with cottonseed 

 oil to which the catalyst, consisting of sodium methoxide in xylene, has 

 previously been added; precautions are taken to exclude air during the 

 mixing of the catalyst and the cottonseed oil. Various proportions of 

 glycerol may be employed. The mixture is continuously agitated over the 

 desired period at a constant temperature. When the proportion of free 

 hydroxyl groups to ester groups is between 1 to 5 and 1 to 2, the reaction 

 mixture consists chiefly of diglycerides, provided that a favorable time- 



^12 A. Haller, Compt. rend., I44, 462-466 (1907). 



*" G. D. Elsdon, Analyst, 38, 8-11 (1913). 



■"■• K. S. Markley, Fatty Acids, Intersoienre, New York, 1947. 



