Recent Development in Chemical Depolymerization of Lignin: A Review

Table 5

Supercritical fluids-assisted lignin depolymerization.

Lignin	Supercritical fluid	Reaction condition		Major products	Yield	Reference
		𝑇 (°C)	𝑃 (MPa)		wt.%
Kraft lignins	Methanol/KOH	290		Catechol	—	[36]
	Ethanol/KOH			Phenol
Organosolv lignin	Methanol/KOH	290		Catechol	—	[36]
	Ethanol/KOH			Phenol
Alkaline lignin	Water	300	25	Catechol	28.37	[37]
				Phenol	7.53
				Cresol	11.67
Organosolv lignin	Water + p-cresol	350–420		2-(Hydroxy-benzyl)-4-methyl-phenol	<75	[38]
Organosolv hardwood lignin	CO2/acetone/water	300–370	10	Syringol	3.6	[39]
				Guaiacol	1.6
				2-Methyoxy-4-methyl-phenol	1.6
Organosolv wheat straw lignin	CO2/acetone/water	300–370	10	Syringic acid	2.2	[39]
				Guaiacol	1.6