Chemical characteristics of lignin isolated from black locust wood after its hydrothermal treatment

The specimens from black locust wood were hydrothermally treated for 1, 4 a nd 8 hours at 140 degrees, and 1 and 4 hours at 160 degrees. In the isolate d dioxane lignins, the following analyses were performed: determination of the functional groups, nitrobenzene oxidation, gel permeation chromatograph y. The obtained results showed that in the first phases of the hydrothermal treatment, degradation of lignin macromolecule and extraction of low molec ular portions into the solution take place predominantly, followed by the c ondensation reactions of lignin.