Lignin and related compounds. V. The hydrogenolysis of aspen wood lignin using rhodium-on-charcoal as catalyst

The hydrogenolysis of aspen lignin using rhodium-on-charcoalas catalyst has been studied. The maximum yield of chloroform-soluble lignin degradation products was obtained at a reaction temperature of 195 °C. Analysis of this chloroform-soluble fraction revealed that the monomeric fraction was composed essentially of the four compounds, 1–4, only, and in a total yield representing at least 40% of the original lignin.Solvent extraction was shown to be preferred over thermal distillation as a preparative procedure for the separation of these phenolic derivatives. The significance of the isolation of these lignin degradation products is discussed.