The
alkaline catalysts commonly applied to alkoxylation are characterized
by a limited spectrum of activity caused by an irreversible termination
of the polyether chains. The presented results show that double metal
cyanide (DMC) catalysts reduce or eliminate the aforementioned adverse
rearrangement of hydroxyl groups. Moreover, DMC catalysts indicate
high activity at low concentrations (ppm range), as expressed by high
polymerization rates. It was demonstrated that decreased concentrations
of DMC catalyst irreversibly influence its reactivity and the dispersity
of the obtained products, as exemplified by the production and determination
of selected polyoxypropylenediols at different concentrations of the
catalyst. Because of their unique advantages, the DMC catalysts are
a very attractive alternative to conventional alkaline catalysts for
the polyaddition of oxiranes. The phenomenon was discussed and explained
by an alteration of reaction rate coefficients at subsequent polyaddition
stages.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.