Ternary Liquid Systems - 3-Heptanol-Water-Acetic Acid and 3-Heptanol-Water-Ethyl Alcohol

1952 ◽  
Vol 44 (7) ◽  
pp. 1668-1670 ◽  
Author(s):  
C. M. Oualline ◽  
M. Van Winkle
Keyword(s):  
Acetic Acid ◽  
Ethyl Alcohol ◽  
Ternary Liquid Systems ◽  
Liquid Systems

Standard of Purity for Cholesterol

1963 ◽  
Vol 9 (2) ◽  
pp. 121-134 ◽  
Author(s):  
Nathan Radin ◽  
Adalbert L Gramza
Keyword(s):  
Acetic Acid ◽  
Sulfuric Acid ◽  
Ethyl Alcohol ◽  
Spectral Region ◽  
Glacial Acetic Acid ◽  
Absolute Ethyl Alcohol ◽  
The Third ◽  
Derivative Method ◽  
Ultraviolet Spectral Region ◽  
Lower Limits

Abstract Three recrystallization technics were used to fractionate five commercial cholesterol products and one artificial mixture. One technic involved the recrystallization of cholesterol from absolute ethyl alcohol, the second technic involved the recrystallization of cholesterol from glacial acetic acid, and the third technic used the dibromide derivative method. The molar absorptivities for the various crystal batches were in the range of 1610 to 1750 L. mole-1 cm.-1 at 620 mµ with a modified Liebermann-Burchard procedure. The molar absorptivities were in the range of 9,800 to 11,500 L. mole-1 cm.-1 at 560 mµ with a modified sulfuric acid-iron method. The original products and the ethyl alcohol recrystallized products showed molar absorptivities at the lower limits of the ranges, while the glacial acetic acid and dibromide derivative recrystallized cholesterol showed molar absorptivities at the higher limits of the ranges. Absorption peaks at 235 mµ for methyl alcohol solutions of the cholesterol preparations were used to estimate cholesterol impurities on the basis of 7-keto cholesterol acetate absorption values. The decrease of absorption in the ultraviolet spectral region established that impurities were removed from the cholesterol preparations studied.

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