Lignin depolymerization via an integrated approach of anode oxidation and electro-generated H2O2 oxidation

Study on the cleavage of alkyl-O-aryl bonds by in situ generated hydroxyl radicals on an ORR cathode

“…The above results conrm that the concentration of in situ generated cOH radicals could be regulated carefully, which is of great help for mechanism study. The degradation rate and product distribution of PBP with changing cOH concentrations Our group has published the results on electrochemical degradation in undivided cells, 26 and this study focuses on the effect of cathodic reaction. It was conrmed that the cation exchange membrane could prevent H 2 O 2 or other ROS, LMCs and the degradation products from diffusing to anodic chamber, so the disturbance from anodic reaction could be avoided.…”

“…Previous study of our group has shown that 59.2% of lignin was depolymerized into LMW aromatic compounds for 1 h electrolysis under atmospheric pressure at 80 C, but more than 20 kinds of products were found. 26 During the research, we also found that the hydroxyl radicals might have played an important role in the cleavage of ether bonds in lignin molecules. However, systematic mechanism study based on product analysis is difficult to carry out because of the complexity of lignin degradation products, which hinders the improvement of the yield and reaction selectivity through further optimization of reaction conditions.…”

Solvent free depolymerization of Kraft lignin to alkyl-phenolics using supported NiMo and CoMo catalysts

“…2,[12][13][14] Oxidative approaches are also known and have also recently been established. 15,16 Reductive depolymerization, followed by hydrodeoxygenation of the obtained fragments to low molecular weight products like phenolics and aromatics has emerged as an attractive strategy. 17,18 During such a catalytic hydrotreatment, a number of reactions may occur, such as hydrocracking leading to depolymerization and hydrodeoxygenation (HDO) to give product mixtures that contain a markedly reduced oxygen content.…”

Greener Routes to Biomass Waste Valorization: Lignin Transformation Through Electrocatalysis for Renewable Chemicals and Fuels Production

“…Zhu et al studied ECO of crude lignin obtained from enzymatic processing of corn straw using aR uO 2 -IrO 2 /Tim esh anode and graphite cylinder felt cathode. [138] The synergistic effect of electrochemical oxidation assisted by in situ-generated H 2 O 2 was investigated and compared to anodic oxidation and H 2 O 2 oxidation alone. As lew of products (29 total compounds, 16 monomers and 13 dimers) were identified after oxidation.…”

“…[138] The integrated method had the most powerful depolymerization capacity and resulted in low molecular weightp roducts,d ecreasedn umber of C 9 groups, disruption of around 67.2 %o f the ether linkages, and a3 0.8 %i ncrease in newly formed hydroxyl groups compared to H 2 O 2 (12.8 %e ther-linkage disruption) or anodico xidation (10.3 %e ther-linkaged isruption) alone. [138] Although all three methods yieldedp roducts that are p-hydroxyphenyl derivatives, products like xylene (proposed to form by alkylation reaction from the migration of aC H 3 group to the aromatic ring) and ethyl benzene (obtained by the cleavage of b-5 bonds) were only observed for the anodic oxidation and the integrated approach. [138] Dimers of a-1, 5-5, b-5, and 4-O-5 types weref ound, indicatingt hat these linkages are unaffected once the dimers have been formed via the oxidative cleavage of adjacent linkages.…”