Affichage des articles dont le libellé est chlorophyll. Afficher tous les articles
Affichage des articles dont le libellé est chlorophyll. Afficher tous les articles

jeudi 1 novembre 2018

Un peu technique, celui-ci

I am asked about the definition of the  "allomerization", and here is it :


The term “allomerization” was transferred into chlorophyll chemistry by Willstätter, who used it to describe then unknown reactions of chlorophylls occurring when they were standing in alcoholic solutions in contact with air . Indeed allomerization is identical to auto-oxidation , including several reactions  that yield a complex mixture of allomers and other alterations products such as solvolysis of the isocycle ring, demetallation, dephytylation and photooxidation .
Concerning the mechanism, it was assumed that allomerization involves as a primary step the auto-oxidation of the Chl enolate anion, formed in small amounts in methanol containing traces of bases and/or metal impurities.