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Titration of cyclopropene esters with hydrogen bromide
Author(s) -
Feuge R. O.,
Zarins Zigrida,
White John L.,
Holmes Raiford L.
Publication year - 1969
Publication title -
journal of the american oil chemists' society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.512
H-Index - 117
eISSN - 1558-9331
pISSN - 0003-021X
DOI - 10.1007/bf02632500
Subject(s) - titration , cyclopropene , hydrogen bromide , chemistry , acetic acid , toluene , hydrogen , bromide , organic chemistry , inorganic chemistry , bromine
Esters of the naturally occurring cyclopropene acids have heretofore been determined by titration with hydrogen bromide in glacial acetic acid. However, highly purified cyclopropenes had an apparent purity of only 83–86% by this method. The catalyzed addition of acetic acid during the titration has been shown to occur. Substituting toluene for the acetic acid not only gives the correct cyclopropene content, but also sharpens the end point of the titration. The new titration is performed at 70–75 C and 1,3‐diphenylguanidine, which is soluble in toluene, should be used as a primary standard. The indicator solution is 0.03% crystal violet in butyric acid. Mono‐ and diglycerides and oxidized fatty compounds must be removed before titration. Oxirane oxygen can be determined by the new procedure, probably with an accuracy greater than that possible with hydrogen bromide in glacial acetic acid.