47 



chance to be saponified than an estergronp of a molecule of tri- 

 glyceride. 



To be able to form an opinion about the surface tensions of tri-, 

 di-, and monogljcerides against saponifying surroundings the behaviour 

 of the laurines was examined by the aid of the apparatus described 

 in the preceding §. The results are found in table 2. 



TABLE 2. 



The laurinic acid was prepared by saponification of trilaurine, 

 obtained from Tangkallak fat, followed by distillation in vacuo. The 

 lower laurines were obtained by esterification of laurinic acid with 

 excess of glycerine at about 200° in the way indicated by van Elüik 

 Thieme *). To purify the dilaurine it was first recrystallized from 

 alcohol (to remove monolaurine), then from benzene (to remove 

 trilaurine). The monolaurine was first recrystallized from petroleum- 

 ether (to remove di- and trilaurine), then from alcohol (to remove 

 monolauryldiglycerine). All the glycerides were perfectly free from 

 oleic acid and free fatty acid. For the rest the constants mentioned 

 in columns 2 — 4 sufficiently express the purity of the substances used. 



The number of drops of monolaurine rising in aqueous solutions 

 could not be determined, as a skin is formed on the boundary of 



1) Solidifying point. 



2) Thesis for the doctorate. Delft (1911). 



