Figure 5.
Lignin conversion (a), yield of p-hydroxybenzaldehyde (b), vanillaldehyde (c) and syringaldehyde (d) with reaction time (the reaction conditions were as follows: NaOH (2 mol/L), 120 °C, 5 bar partial pressure of oxygen in 20 bar total pressure, CL0=60.00 kg/m3, Ccatalyst=3 g/L and the lignin conversion=(C0-Ct)/C0, where C0 is the initial concentration of lignin, and Ct is the concentration of lignin at any reaction time).