132 



of grams of potassium hydrate to neutralize the vohitile acids in 100 grams 

 of butter fat, we have the following proportion: 



.005612 X 34.48 X 20 = 3.86 grams of KOH 



In order to calculate the molecular weight of the volatile acids, we first 

 calculate the weight of the soluble acids. To do this we make use of the 

 amount of insoluble acid or Hehner Value. The per cent, of insoluble acid 

 was found to be 87.54, mean molecular weight 254.8. The molecular weight 

 of the glycerides of tlie insoluble acids would be (254.8)3 + 38 = 802.4 mean 

 molecular weight of the insoluble acids as triglycerides."^ 



Then from the following proportion we obtain the per cent., or parts per 

 hundred of the triglycerides of the insoluble acids. 764.4 : 802.3 :: 87.54: x, 

 X = 91.87 grams per hundred of glycerides of the insoluble acids. 



Now 100 — 91.87 = 8.13 glycerides of the soluble acids. Since 3K0H 

 = 92 parts of glycerol or 38 parts of C3H2, then from the quantity of KOH 

 reciuired to neutralize the soluble acids in 100 grams of fat, which was found 

 to be equal to 3.86 grams, we can calculate the per cent, of C3H2 combined 

 with the soluble acids by means of the following proportion; 186. 36:3. 86::38:y, 

 X = .87 per cent, of C3H2. If we subtract this from the glycerides of Ihe sol- 

 uble acid we have then the amount of soluble acids in 100 grams of butter fat. 



8.13— .87 = 7.26 

 and therefore the molccMlar weiglit is determined from tiic following pro- 

 portion: 



x:56.12::7.26:3.86. x = 104.5 mean molecular of the volalile acids in this 

 sample of Ijutter fat. 



The mean molecular weight of the volatile acids of butter varies from 

 9o to 130 as recorded bj- Richmond and Lewkowitsch. This is ([uite natiual 

 and from the molecular weight of the different volatile acids entering into 

 the glycerids we can expect a variation in the mean molecular weight. A 

 slight variation of the different acids would cause a marked increase or de- 

 crease in the mean molecular weight. The molecular weights of the different 

 volatile acids entering into the glycerids we can expect a variation in the 

 mean molecular weight. This fact adds weight to the assumption that the 

 proportion of volatile acids are not constant. A slight variation of the dif- 

 ferent acids would cause a marked increase or decrease in the mean molecular 

 weight. The molecular weights of the different volatile acids entering into 

 the triglycerides of butter fat are as follows: 



'For the saponificuli )n of a t.i^lvceride bv K OH i.s expressed hv the following e<|Uation. 



fR. " ■ 



C,H:i'R, + 3 K OH = C3 H,(OH)3 -t- K (R, R, R,) 



IR> 

 M. W. of CjHj = 41 .'. 41 — 3 = 38 sin e the 3 h.v<lro;on .Ttoms are taken b.\- the acids. 



