A method of converting lignin to phenolic compounds and dicarboxylates in high yield is described. The method involves the use of peroxy acids to react with lignin at a moderated treatment conditions. The peroxy acids can be used along or in combination of other catalysts that have the capability to lower the molecular weight of lignin. A phenolic compounds yield is achieved (>60%) and these phenolic compounds represents high value precursors for various applications include but not limited to antioxidants, health improvement agents, anticorrosive agents, liquid fuel components and performance enhancing agents, resin and adhesives. Dicarboxylic acids can be used for polymer applications or hydrodeoxygenation to hydrocarbon fuel.