As one of the few renewable aromatic resources

the research of depolymerization of lignin into high-value chemicals has attracted extensive attention in recent years. Catalytic wet aerobic oxidation (CWAO) is an effective technology to convert lignin like sodium lignosulfonate (SL)

a lignin derivative

into aromatic aldehydes such as vanillin and syringaldehyde. However

how to improve the yield of aromatic aldehyde and conversion efficiency is still a challenge

and many operating conditions that significantly affect the yield of these aromatic compounds have rarely been investigated systematically. In this work

we adopted the stirred tank reactor (STR) for the CWAO process with nano-CuO as catalyst to achieve the conversion of SL into vanillin and syringaldehyde. The effect of operating conditions including reaction time

oxygen partial pressure

reaction temperature

SL concentration

rotational speed

catalyst amount

and NaOH concentration on the yield of single phenolic compound was systematically investigated. The results revealed that all these operating conditions exhibit a significant effect on the aromatic aldehyde yield. Therefore

they should be regulated in an optimal value to obtain high yield of these aldehydes. More importantly

the reaction kinetics of the lignin oxidation was explored. This work could provide basic data for the optimization and design of industrial operation of lignin oxidation.