132 EXPERLM1-:XT STATION. [Jan. 



question of distillation of the acids the process would be less 

 difficult, but for fractionation, using a Bruehl or similar type 

 aj^paratus, it proved almost impossible, in case of the higher 

 acids, to prevent solidification in the side neck (outflow tube). 

 The danger arising from a plugged apparatus at the high tem- 

 jierature involved has also to be taken into account. An attempt 

 Avas made to heat the tube and keep the acidsdiquid by means of 

 a hot-water jacket, also by an electrically heated asbestos cover- 

 ing, but neither process fully met the requirements of the case. 

 The slow distribution of heat in vacuo is, of course, one of the 

 obstacles in the way. 'For the distillation of solids of high melt- 

 ing point Bredt and A. van dor Maaren-Jansen ^ devised an 

 elaborate piece of apparatus having a flask and receiver of spe- 

 cial construction, and an overflow tube heated by electricity, but 

 it is hardly suited for a general laboratory or for handling any 

 considerable quantity of material. 



There are two other conditions necessary for a successful dis- 

 tillation of fatty acids, namely, absence of moisture and a cur- 

 rent of hydrogen or carbon dioxide to prevent bumping and to 

 lessen decomposition. Overlapping of the acids in difl^erent 

 fractions cannot be obviated entirely, and if an unsaturated acid 

 was present in the original, it will probably appear in nearly 

 every fraction. 



Students under the direction of Professor Burrows of the 

 University of Vermont have applied this process for a partial 

 separation of the insoluble acids of several oils with a fair meas- 

 ure of success. With all due allowance for the possibilities of 

 the method in the production of pure saturated fatty acids, the 

 inherent difficulties render it inadvisable in most instances. 



B. Crystai^lizatioi^t from Alcohol. 

 Crystallization in this connection is practically limited in its 

 application to the removal of a small amount of impurities, 

 especially unsaturated acids. It can hardly be considered other 

 than a supplementary treatment, though excellent for that pur- 

 pose, to follow either of the distillation methods. Dry neutral 

 alcohol suitable for such work can be prepared by distillation 

 after treatment with caustic lime. In dissolving the acids care 



« Liebig'a Ann. Chem., 354, 367 (1909). 



