III. INDUSTRIAL PREPARATION 



497 



tiratnuMit of the extract, which freezes out much of the extracted lipid ma- 

 terial, and by removal of solvent, yields a tocopherol-enriched oil.'" 



The details of procedure and e(iuipment used for the solvent extraction 

 of vegetable oils with litiuid propane or other hydrocarl)oiis have lieen de- 

 scribed but without much information concerning the potency of the con- 

 centrates obtained.^* "^* Also, fractional crystallization of cottonseed oil from 

 solvents yields a tocopherol-containing fraction. ^^ 



Adsorption chromatography is used to prepare relatively pure individual 



TABLE I 



Description op Some Typical Commercially Available 

 Tocopherol Preparations 



tocopherols, usually on a small scale, as in analytical procedures.^' ^^ How- 

 ever, chromatography can be adapted to large-scale production. '^"'^ 



Molecular distillation of tocopherol-containing oils has proved to be an 

 efficient and practical procedure for preparing potent concentrates of natu- 



'0 W. D. McFarlane, U.S. Pat. 2,497,317 (Feb. 14, 1950). 



" N. D. Embree and N. H. Kuhrt, U.S. Pat. 2,454,692 (Nov. 23, 1948). 



12 A. W. Hi.xson and R. Miller, U.S. Pat. 2,508,387 (May 23, 1950). 



13 W. M. Leaders and F. A. Norris, U.S. Pat. 2,521,234 (Sept. 5, 1950). 

 " W. S. Singleton and A. E. Bailey, Oii & Soap 21, 224 (1944). 



If* A. Emmerie, Ann. N. Y. Acad. Set. 52, 309 (1949). 



16 0. Isler, Chimia (Switz.) 5, 249 (1951). 



1' J. C. Drummond, British Pat. 517,401 (Jan. 29, 1940). 



18 I. G. Farbenindustrie, German Pat. 717,483 (Jan. 29, 1942). 



