Conversion of Hydroxylamines to Polyurethanes
The conversion of hydroxylamines to urethanes and polyurethanes has been described in the literature . The carbonyl of the carbonate linkage provides a ready coreactant for the hydroxylamine, and high molecular weights have been reported using this procedure (Fig. 12.16) with removal of the phenol coproduct and design of the R group to inhibit formation of the cyclic urethane. The cost of diphenyl carbonate, its high unit ratio, and the large volume of phenol coproduct could be an inhibiting factor in implementation. An alternative direct reaction of phosgene or C02 with hydroxylamines would yield mixed cyclic products like 2-oxazolidinone or hydroxyethyl imidazolidinone (Fig. 12.17) or mixed urethane/carboxylate chain functionality due to the reactivity of both amines and hydroxyls for the electrophilic carbonic acid derivatives depending on initial reagents.