Oxidized polyethylenimine

Abstract

Abstract Polyethylenimine (PEI) has been oxidized with aqueous hydrogen peroxide to yield a hygroscopic, water‐soluble, slightly basic, yellow polymeric solid (OPEI) containing about 25% oxygen. Some chain degradation accompanies oxidation. The nature of the product varies somewhat with preparative conditions. OPEI, in the presence of strong alkali, reduces silver salts and peptizes a portion of the silver. By use of infrared, ultraviolet, and proton magnetic resonance spectroscopy together with qualitative testing, OPEI has been found to contain carboxyl groups, unoxidized primary amine groups, tertiary amine oxide, small amounts of aldehyde and nitrone groups, and a considerable amount of secondary amide. The probable reaction sequence is: PEI → dialkylhydroxylamine → nitrone → oxazirane → rearranged product. Oxazirane groups appear to be absent, as well as oxime, nitro, nitrite, and nitrate. The groups which reduce silver salts are not known with certainty but are probably of the hydroxylamine type. The carboxyl content of OPEI is associated with the lower molecular weight species which are present.