Table 3 Some studies reporting guaiacol, vanillin and related compounds in depolymerized lignin

Steam treated softwood and hemp lignin

Base-catalyzed depolymerization

Guaiacol, vanillin, catechol

[69]

Organosolv lignin

Base-catalyzed depolymerization

Guaiacol, syringol, syringaldehyde,

[70]

Spruce lignin

Hydrogenolysis/extraction

Ethylguaiacol, propylguaiacol,

[71]

Dealkaline lignin

Solid acid catalysts

Vanillin, guaiacyl acetone, homovanillic acid

[72]

Birch wood lignin

Hydrogenolysis with Ni-based catalysts

Propyl guaiacol and propyl syringol

[73]

Organosolv switchgrass lignin

Depolymerization and hydrodeoxygenation with formic acid and Pt/C

Guaiacol, 4-methylguaiacol, homovanillyl alcohol

[74]

Organosolv hardwood lignin

Depolymerization in supercritical carbon dioxide/acetone/water fluid

Guaiacol, 2-methoxy-4-methyl-phenol, syringol

[75]

Kraft lignin

Oxidation in aqueous methanol at acidic pH

Vanillin, methyl vanillate

[76]

Kraft lignin (Indulin AT)

Base (NaOH) catalyzed depolymerization at 220 °C

Guaiacol, vanillin, acetovanillone, vanillate, 4-hydroxybenzoate

This study