Process for the electrochemical cleavage of lignin at a diamond electrode

Abstract

The invention relates to a process for the electrochemical cleavage of lignin by means of a diamond electrode and also to a process for producing vanillin and derivatives thereof by electrochemical cleavage of lignin in a solution having a pH≦11.

1 . A process for the degradation of lignin comprising electroyzing an aqueous solution comprising lignin in an electrochemical cell with a diamond electrode to produce a lignin degradation product, wherein the lignin has a yield of hydroxybenzaldehyde derivatives and/or phenol derivatives higher than  5 % by weight, and the aqueous solution has a PH≦11. 
     
     
         2 . The process according to  claim 1 , wherein the aqueous solution is acidic. 
     
     
         3 . The process according to  claim 1 , wherein the diamond electrode is a boron-doped diamond electrode. 
     
     
         4 . The process according to  claim 1 , wherein the lignin degradation product is continuously removed from the electrochemical cell. 
     
     
         5 . The process according to  claim 1 , wherein the lignin degradation products arc product is removed by steam distillation. 
     
     
         6 . The process according to  claim 1 , wherein the lignin degradation product is removed by continuous extraction using an organic solvent. 
     
     
         7 . The process according to  claim 1 , wherein the lignin degradation product is selected from the group consisting of guaiacol, vanillin and acetovanillone.