@Article{jrm.2023.030122,
AUTHOR = {Zhimei Li, Kuan Tian, Keping Wang, Zhengyi Li, Haoli Qin, Hu Li},
TITLE = {Acidic Magnetic Biocarbon-Enabled Upgrading of Biomass-Based Hexanedione into Pyrroles},
JOURNAL = {Journal of Renewable Materials},
VOLUME = {11},
YEAR = {2023},
NUMBER = {11},
PAGES = {3847--3865},
URL = {http://www.techscience.com/jrm/v11n11/54426},
ISSN = {2164-6341},
ABSTRACT = {Sustainable acquisition of bioactive compounds from biomass-based platform molecules is a green alternative for
existing CO<sub>2</sub>-emitting fossil-fuel technologies. Herein, a core–shell magnetic biocarbon catalyst functionalized
with sulfonic acid (Fe<sub>3</sub>O<sub>4</sub>@SiO<sub>2</sub>@chitosan-SO<sub>3</sub>H, MBC-SO<sub>3</sub>H) was prepared to be efficient for the synthesis of
various N-substituted pyrroles (up to 99% yield) from bio-based hexanedione and amines under mild conditions.
The abundance of Brønsted acid sites in the MBC-SO<sub>3</sub>H ensured smooth condensation of 2,5-hexanedione with a
variety of amines to produce N-substituted pyrroles. The reaction was illustrated to follow the conventional PallKnorr coupling pathway, which includes three cascade reaction steps: amination, loop closure and dehydration.
The prepared MBC-SO<sub>3</sub>H catalyst could effectively activate 2,5-hexanedione, thus weakening the dependence of
the overall conversion process on the amine nucleophilicity. The influence of different factors (e.g., reaction temperature, time, amount of catalyst, molar ratio of substrates, and solvent type) on the reaction activity and selectivity were investigated comprehensively. Moreover, the MBC-SO<sub>3</sub>H possessed excellent thermochemical stability,
reusability, and easy separation due to the presence of magnetic core-shell structures. Notably, there was no activity attenuation after 5 consecutive catalytic experiments. This work demonstrates a wide range of potential applications of developing functionalized core-shell magnetic materials to construct bioactive backbones from
biomass-based platform molecules.},
DOI = {10.32604/jrm.2023.030122}
}