posted on 2024-02-22, 13:38authored byHanqing Zhao, Weiqiang Yu, Chun Gu, Jie Xu, Song Shi, Jin Gao, Yajing Zhang
In
recent years, lignin and its derivatized phenolic
compounds
have garnered significant attention in the scientific community due
to their sustainability. However, the reaction for converting lignin-based
phenolic compounds into other fine chemicals presents several challenges,
including stringent reaction conditions, catalyst deactivation, and
low reaction efficiency. Herein, an efficient synthesis strategy was
proposed for the etherification of lignin-based phenolic compounds
with a green methylation reagent of dimethyl carbonate under mild
conditions, constructing a chemical barrier wall within the microenvironment
of the 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) catalyst system via
inorganic bases to enhance the catalytic activity. Excellent etherification
conversion and selectivity of lignin-based ether (>99.5%) was obtained
at 145 °C for 60 min. A possible reaction mechanism was also
postulated based on the results. This work demonstrates that the construction
of barrier walls reduces the loss of active sites of the DBU system,
concurrently enhancing the catalytic efficiency, which has a potential
application prospect.