Nitrogen-modified lignins was produced from the reaction of ammonia and lignins under proper conditions. ^1^3C and ^1H-^1^3C 2D-NMR HMQC spectroscopy was applied to detect the changes of lignin molecule during oxidative ammonolysis. Results showed that fragmentation of lignins molecule was highly drastic during oxidative ammonolysis. Probably oxidative modifications of moieties on the surface of lignin molecule (such as formation of CHO and COOH from CH~3 or CH~2) took place. Then nitrogen was incorporated into the lignin. However, no obvious changes was found in the highly-condensed lignin inner structures.

Key words: NUCLEAR MAGNETIC RESONANCE, CHEMICLAL MODIFICATION, BIOMACROMOLECULE, AMMONIATION