Depolymerization of lignin using solid acid catalysts

A process for the conversion of lignin to substituted phenolic compounds, said process comprising the steps of:

• i. charging lignin and a catalyst in the ratio ranging between 0.1:1 to 1:0.1 into a reactor followed by charging a solvent, wherein the catalyst consists of a heterogeneous solid acid catalyst;
• ii. optionally flushing the reactor with nitrogen, argon, helium, hydrogen or air;
• iii. adjusting the reactor to operate at atmospheric pressure and heating the reactor to a temperature in the range of 50 to 300° C. with stirring;
• iv. raising the stirring speed to 10 to 2000 rpm after stabilizing at the temperature;
• and
• v. carrying out a reaction for a period in the range of 0.1 to 96 hours to obtain substituted phenolic compounds.