Methacrylic acid (MAA) and 2-hydroxyethyl methacrylate (HEMA) were cografted with acrylonitrile (AN) onto polyethylene fiber by radiation-induced graft polymerization. The cyano groups
produced were converted to amidoxime groups (−C(NOH)NH2) by reaction with hydroxylamine
(NH2OH) to recover uranium in seawater. Various weight ratios of AN/MAA or AN/HEMA in
the monomer mixture for cografting generated MAA- and HEMA-cografted amidoxime (AO) fibers
with various hydrophilicities. The amidoxime group density and water content were balanced
to enhance the uranium adsorption from seawater. MAA-cografted AO fibers exhibited a higher
adsorption rate than HEMA-cografted AO fibers. The optimum value of the weight ratio of AN/MAA = 60/40 in the monomer mixture was observed both in a submerged mode at an ocean site
and in a flow-through mode in the laboratory. The amount of uranium adsorbed was 0.90 g/kg
of the MAA-cografted AO fiber at 293−298 K after 20 days of contact at the ocean site.
o-Imidoquinones, a rather rare class of compounds, are prepared from anilides by the action of Dess-Martin periodinane (DMP) and water. Their chemistry has been extensively investigated and found to lead to p-quinones and polycyclic systems of diverse molecular architectures. Applications of this methodology to the total synthesis of the naturally occurring compounds, epoxyquinomycin B and BE-10988, are described. Finally, another rare chemical entity, the ketohydroxyamide moiety, has been accessed through this DMP-based synthetic technology, and its reactivity has been studied. Among its most useful reactions is a set of cascade heterocyclic annulations leading to a variety of polycyclic systems of possible biological relevance.
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