COMPOSITION OF NATURAL FATS AND OILS 181 



The latter investigators were able to separate caprylic, capric, lauric, my- 

 ristic, palmitic, and erucic acids from each other, although more satis- 

 factory results obtained when the methyl esters were fractionated. The 

 methyl esters of saturated and unsaturated acids, as well as the methyl 

 esters of certain dicarboxylic acids,^^ can be separated by distillation.^^ 



Many types of packing are used in the fractionating columns. These in- 

 clude Lessing rings made of 50-mesh copper screen, ^'^'* glass modifications of 

 the single-turn and double-turn wire helices previously used,^"^ and spiral 

 continuous wire coil packings in fractionating columns having separate 

 sleeve-like metal vacuum jackets. ^"'^ Klem^"^ successfully employed the 

 last type for the difficult separation of methyl palmitate, methyl stearate, 

 methyl oleate, and methyl elaidate from each other. Fenske and co- 

 workers,^*** after investigating many types of packing, have reported best 

 results with wire or glass helices, carding teeth, and jack-chains. A num- 

 ber of other workers have found wire helices especially efficient. ^"^"^"^ 

 Methyl palmitate and methyl stearate were fractionated very effectively by 

 Schoenheimer and Rittenberg™ by means of tightly fitting metal helices. 

 Price and McDermott^^^ have described a simple method for preparing 

 glass helices, while Longenecker^^ used single-turn glass helices in the in- 

 vestigation of the acids of beef tallow, peanut oil, the liquid esters of butter 

 fat and for separating the methyl esters of the butter fatty acids. ^^° By far 

 the most effective packing is the conical type developed by Stedman,^^^ 

 which has been further described by Bragg. ^^'^ In industrial columns, a 

 very efficient bubble-cap type is employed, but this cannot be satisfactorily 

 used on the laboratory scale. For a further discussion of fractionating 

 columns, the reader is referred to Longenecker^^* and Ralston.^- 



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 (1933). 



'"^ W. J. Podbielniak, Ind. Eng. Chem., Anal. Ed., 5, 119-135 (1933). 



103 A. Klem, Nature, 142, 616 (1938). 



'"^ M. R. Fen.ske, C. O. Tongberg, and D. Quiggle, Ind. Eng. Chem., 26, 1169-1177 

 (1934). 



'»s M. R. Fenske (to Pennsylvania State College), U. S. Patent No. 2,037,317 (Apr. 14, 

 1936). 



'"« C. O. Tongberg, S. Lawroski, and M. R. Fenske, Ind. Eng. Chem., 29, 957-958 

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"» H. E. Longenecker, Oil & Soap, 17, 53-57 (1940). 



