CHEMICAL METHOD FOR LIGNIN DEPOLYMERIZATION
The present invention claims a new method to depolymerize and/or modify lignin or lignin related compounds by using copper, a copper coordination compound and peroxide in an aqueous solution. The copper coordination compound is applied in concentrations below 20 % preferably at 0.001-5 % in aqueous solutions. The coordination compounds include compounds containing nitrogen, such as pyridine, histidylglycine, phthalocyanine, acetonitril; containing a hydroxyl group, such as catechol; containing ether, such as 18-crown-6; containing sulfur, such as mercaptosuccinic acid; or containing olefinic double bonds, such as 1,3-cyclohexadiene. Peroxide can be added externally as hydrogen peroxide or as organic perioxide or as peracid or can be produced in the lignin containing solution by peroxide producing chemical reactions.