98 



MASS. EXPERIMENT STATION BULLETIN 166. 



Titration of excess alkali. 



R in the graphic formula of the fatty acids represents C and H in differ- 

 ent amounts, according to the acid, but in the proportion of CnHjn+i, 

 except in the case of unsaturated and of dibasic acids. 



Saponification Numbers of Triglycerides. 



Glyceride. 



Formula. 



Molecular 

 Weight. 



Saponifica- 

 tion 

 Number. 



Acetin, . 



Butyrin, 



Valerin, 



Caproin, 



Caprylin, 



Capri n, 



Laurin, . 



Myristin, 



Palmitin, 



Stearin, 



Arachin, 



Olein, . 



Erucin, . 



Linolin, 



Linolenin, 



Clupanodonin, 



Ricinolein, . 



Dihydroxystearin, 



(CHaCOOsCsHs 



(C3H7COO)3C3H6 

 (C4H9COO)3C3H6 



(C6HaCOO)3C3H5 



(C7Hl6COO)3C3H5 

 (C9Hl9COO)3C3H5 

 (CllH23COO)3C3H5 

 (Cl3H27COO)3C3H5 

 (Cl6H3lCOO)3C3H5 

 (Cl7H36COO)3C3H5 



(CisHssCOOsCsHo 



(;Cl7H33COO)3C3H5 



(C2lH4lCOO)3C3H5 



(Cl7H3lCOO)3C3H5 



(Cl7H29COO)3C3H5 



(Cl7H27COO)3C3H5 



(Cl7H32.0H.COO)3C3H6 



(Cl7H33(OH)2COO)3C3H6 



218.112 

 302.208 

 344.256 

 386.304 

 470.400 

 554.496 

 638.592 

 722.688 

 806.784 

 890.880 

 974.976 

 884.832 

 1,053.024 

 878.784 

 872.736 

 866.688 

 932.832 

 986.880 



771.732 

 556.981 

 488.950 

 435.729 

 357.832 

 303.562 

 263.586 

 232.914 

 208.636 

 188.941 

 172.644 

 190.233 

 159.848 

 191.542 

 192.869 

 194.215 

 180.444 

 170.562 



Supplementary Notes. — The term "saponification or saturation equiv- 

 alent," as employed by Allen ^ and others, indicates the grams of fat that 

 are saponifiable with one equivalent of potassium hydroxide in grams 

 (56.108); in other words, the grams of fat saponifiable with 1 liter of N 

 potassium hydroxide. 



Saponification equivalent (sq) 



Saponification number (s) = 



56108 



s 



56108 

 sq 



mg. of fat. 

 c.c. N alkali' 



The lower the molecular weight of the fatty acids (or esters) the more 

 alkali will be required to satisfy 1 gram, and the higher will be the saponifi- 

 cation number. The presence of free fatty acids increases the saponifica- 

 tion number, and unsaponifiable matter decreases it. The majority of oils 



' Commercial Organic Analysis, 2, pp. 15, 16 (1910). 



