Sharp [sup.13]C resonances at 177 and 135 ppm were identified to be due to mellitic acid using addition of a standard of mellitic acid.
The only aromatic carboxylic acid that exhibits such structural features is mellitic (benzenehexacarboxylic) acid.
The charred residues seem to not be stable; subsequent oxidation results in the release of free mellitic acid and other benzenepolycarboxylic acids in subsoil SOM, resonating at 135 and 177 ppm in the [sup.13C]-NMR spectra.
In addition, our work continues to investigate the network polymers, which are derived from mellitic trianhydrides (MTA) in reaction with the diamines, sodium salts.
Mellitic trianhydride (MTA), 4,4[prime]-oxydianiline (ODA), and 2,5-diaminobenzenesulfonic acid (DABSA) were obtained from Aldrich Chemical Co., 4,4[prime]-Diaminostilbene-2,2[prime]-disulfonic acid (DASBDSA) was purchased from Lancaster Synthesis Ltd.