The present thesis is concerned with two topics in the field of material-based biorefineries. The first part addresses the reaction behavior of mono- and polysaccharides under ammoxidation (a.) conditions. By a., lignin can be turned into a soil improving material. Technical lignin always contains a certain amount of carbohydrates, which makes exact knowledge of their reaction behavior and the potential toxicity of their reaction products necessary. Therefore, cellulose, xylan, xylose and glucose were subjected to different a. conditions and analysed by GPC, GC/MS after derivatization and algae growth inhibition tests. Polysaccharides did show degradation, but produced only small amounts of low molecular and phytotoxic substances. Monosaccharides produced over 100 different compounds, N-heterocyclic compounds (imidazoles, pyrazines, pyridines) as well as open-chain compounds (sugars, amino sugars, aldonic acids, -hydroxyamides, -amino acids). The kinetics and reaction mechanisms were investigated and discussed. In the algae growth inhibition test, basic heterocycles of intermediate hydrophilicity showed the highest response, while more hydrophilic or less basic ones exhibited no inhibition. The second part is concerned with the preparation, characterization and reaction behavior highly periodate-oxidized cellulose, i.e. “dialdehyde cellulose” (DAC). DAC may be produced from various resources, such as microcrystalline cellulose, pulp, waste paper or cotton linters. The prepared solutions and their reactions in homogeneous phase can conveniently be analyzed by liquid state NMR. Analysis by size exclusion chromatography reveals a strong dependence of the molar mass from dissolution conditions, eluent and storage of the samples. By reaction with multifunctional amines, dialdehyde cellulose is cross-linked. The crosslinking products are analyzed by NMR, FTIR and DSC.