Oxidative catalytic valorization of industrial lignin into phenolics: Effect of reaction parameters and metal oxides

Catalytic aerobic oxidation of lignin-based vanillyl alcohol under base–free conditions over an efficient and reusable LaFeO3 perovskite for vanillin production

“…It is noteworthy that the yield of vanillin when isopropanol was used as the solvent was higher than those of methanol and ethanol, which might be due to the change in their acidity and dielectric constant values with increasing carbon chains. 36 Furthermore, ethanol was less acidic and more basic, and was inferior to methanol acting as a quenching agent to control the repolymerization reaction by reacting with the generated intermediates. 37 As a result, the yield of vanillin was lower than that of methanol as the solvent.…”

Structure elucidation of prot, alkali and dealkaline lignin(s) by NMR, FT-IR and Py-GC/MS: effect of solid acid and base catalysts

“…Alkali lignin was bought from Sigma Aldrich with 99.9% purity, and dealkaline lignin was purchased from TCI chemical, Tokyo as commercial lignin. The metal oxides MgO and CaO were also acquired from Sigma Aldrich, and ZSM-5 and Y-zeolite were bought from Zeolyst in the form of H-ZSM-5 (30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40) and HY (8)(9), respectively. All of the obtained catalysts were thermally pretreated before applying them to the reaction.…”

“…The total phenolic content was noticed to be 78.7% during the non-catalytic reaction, and it increased to 83% while In our previous study, we reported that the presence of Co 3+ and Co 2+ helps in breaking the syringyl unit present in lignin into acetosyringone (S-type phenolic) with CeO 2 (Ce 4+ and Ce 3+ ) promoting this reaction. 30 Thus, the ionic character helps to target the selective compound formation from lignin breaking.…”

“…In our previous study, we reported that the presence of Co 3+ and Co 2+ helps in breaking the syringyl unit present in lignin into acetosyringone (S-type phenolic) with CeO 2 (Ce 4+ and Ce 3+ ) promoting this reaction. 30 Thus, the ionic character helps to target the selective compound formation from lignin breaking. Here, two new syringols (S-type compound), e.g.…”

Critical Techniques for Overcoming the Diffusion Limitations in Heterogeneously Catalytic Depolymerization of Lignin

“…It can promote the solubility of residual undissolved lignin and suppress the side reaction, and thus promote the selectivity of the desired products. The isolated lignin has low solubility in water and single organic solvent such as ethanol and acetone, but moderate solubility in alkaline and mixtures of organic solvent and water with a good solvent factor at room temperature [9a,54] . In contrast, both organosolv and Kraft lignin were entirely dissolved in a water: ethanol mixture (1 : 1) at 115 °C and the aggregation was suppressed completely [45] .…”