Methylester of rapseed oil

Jeffrey W. Chisholm JWCHISH at AC.DAL.CA
Sun Oct 2 20:42:06 EST 1994


>I need information or referanses on the subject methylesters of rapseed oil, 
>including prosessing of rapseed oil and the prosess for methyesterification.


>Can anyone give me information or referanses by Email ?

Rapseed oil, like any other plant derived oils is obtained by an organic
solvent extraction method.  You should be able to find the methodology in
any good lipids text.

    As for the preparation of fatty acid methyl esters from lipids,
there are 3 common methods.  1. The most common involves a methanolic
Boron triflouride reaction, however, this method has never worked all
that well for me.  2. The best method is probably by methylation using
diaziomethane, this method gives almost 100% esterification, but is
extremely dangerous unless the proper facilities and technical expertise
are available.  The safest way I have seen is by preparing diazomethane
in the mini diazald apparatus available from Aldrich (I think), even
with this apparatus, the diazomethane preparation must be performed
in a fume hood with lots of plexiglass and all glass-ware must be
carefully examined to avoid sharp edges as diazomethane is extremely
explosive.  3. The third method and the one I have most often used involves
acetyl chloride in methanol.  This method works well and can be done
easily in a teflon stoppered culture tube.  The reference is:

Lepage, G. and Roy,C.C. (1986) J. Lipid Res. 27, 114-120.

It should be noted that the original method uses benzene as a solvent,
I have found hexane can be used instead without any change in yield.
This method is extremely useful in preparing ultra-pure methyl ester
samples for gas chromatography.  There are many books and journal articles
available on the gas chromatography of lipids that explain the
methyl esterification of lipids further.

Hope this helps :)

Jeffrey W. Chisholm
Lipoprotein Research Group
Department of Biochemistry
Dalhousie University
Halifax, Nova Scotia, Canada

Jwchish at ac.dal.ca



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