Free radical reaction promoted by ionic liquid: a route for metal-free oxidation depolymerization of lignin model compound and lignin

Ionic liquid 1-benzyl-3-methylimidazolium bis(trifluoromethylsulfonyl)-imide ([BnMIm][NTf2]) can promote the generation of the (OOH)-O-center dot free radical and thereby efficiently transformed the beta-O-4 lignin model compound 2-phenoxyacetophenone into benzoic acid and phenol using O-2 as the oxidant. Furthermore, the IL-based metal-free catalytic system can also depolymerize other lignin model compounds and organosolv lignin effectively.