09.12.2012 Views

Food Lipids: Chemistry, Nutrition, and Biotechnology

Food Lipids: Chemistry, Nutrition, and Biotechnology

Food Lipids: Chemistry, Nutrition, and Biotechnology

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

Figure 4 Reaction mechanisms for the chemical inter- <strong>and</strong> intraesterification of two triglycerides<br />

via the carbonyl addition mechanism. (Adapted from Ref. 30.)<br />

stant 3k (Fig. 5). Not all possible exchanges produced a net change in triacylglycerol<br />

composition, leading to 2k <strong>and</strong> k rate constants.<br />

B. Claisen Condensation<br />

In Claisen condensations, the sodium methoxide removes an acidic hydrogen from<br />

the carbon � to the carbonyl carbon, yielding an enolate ester [23]. This reaction<br />

produces a carbanion, a powerful nucleophile (Fig. 3B). This nucleophile will attack<br />

carbonyl groups, forming a �-keto ester intermediate <strong>and</strong> a glycerylate. The glycer-<br />

Copyright 2002 by Marcel Dekker, Inc. All Rights Reserved.

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!