KINETICS OF THE ALKALINE NITROBENZENE OXIDATION OF LIGNIN IN RICE STRAW

Alkaline nitrobenzene was used to oxidize and thereby depolymerize lignin in rice straw to aldehydes, and the conditions needed for a high yield of aldehydes were examined. Of the concentrations tested, 5% (v/v) nitrobenzene and 2 N potassium hydroxide were optimum. A kinetic model for the simulation of the formation of aldehydes has been proposed. In the model, the nucleus, which gave an aldehyde, was assumed to consist of components with different susceptibilities to degradation, although the degradation of each component was taken to obey first-order kinetics. The heterogeneity of susceptibility to degradation was represented by a normal Gaussian distribution with respect to the free energy of activation for first-order degradation. The model simulated fairly well the transient changes in the concentrations of aldehydes observed at different temperatures.