Mid- and near-infrared spectroscopic investigations ofN-phenylmaleimide (NPM)/amine reactions

The reactions between N-phenylmaleimide (NPM) and several amines have been examined by both mid-infrared (mid-IR) and near-infrared (near-IR) spectroscopy. Significant overlap exists among several functional groups of NPM/amine systems in the mid-IR spectral region. Interference between these absorptions significantly reduces the utility of mid-IR spectroscopy for quantitative studies of NPM/amine reaction kinetics. In contrast, the absorption bands of these functional groups are well separated in near-IR spectra. The ability of near-IR spectroscopy for studying the kinetics of the reactions between the maleimide-containing compound with amines is clearly established. Near-IR absorptions suitable for quantitative studies of these reactions are identified.