Synthesis and Stability of Aryl Bis(nitrile oxides) With Potential as Curing Agents for Polysulfide Sealants

Abstract

Several aromatic bis( nitrile oxides) have been prepared as potential curing agents for sealants produced from thiol -terminated polysulfide liquid polymers. All were obtained by dehydrohalogenation of α-halo oximes and the requisite aldehydes were synthesized from either the dimethyl derivatives or the chloromethylated hydrocarbons. The direct chloromethylation of naphthalene which offered a convenient route to the naphthalene-1,4- and 1,5-bis(carbonitrile oxides) was re-examined. Also prepared were naphthalene-2,6-bis(carbonitri1e oxide), anthracene-9,10-bis(carbonitri1e oxide) and 4,4′-sulfonylbisbenzonitrile dioxide. The course of the reaction between naphthalene-2,3-dicarbaldehyde and hydroxylamine was established and shown to differ from that involving phthalaldehyde. Stabilities of the nitrile oxides at -15º, 4º and 25º were assessed by spectroscopic means.