Catalysts play a crucial role in industrial processes, enabling them to be performed under economic conditions. Their stability and selectivity are decisive parameters. A current work by Dr. Ding, postdoctoral fellow in the Heumann group, in close collaboration with the group of Prof. Sheng Dai from the Oak Ridge Laboratory, USA and Prof. Zhen-An Qiao from Jilin University in China, discusses the development of a highly stable iron-based catalyst for the regiospecific ortho-oxidation of phenol to catechol (1,2-dihydroxybenzene). Dihydroxybenzenes are a significant class of compounds and play an important role in pharmaceuticals, polymerization inhibitors and coatings, hence triggering considerable efforts to study transformations that give rise to them.
In the presented work, atomically dispersed iron sites on carbon nanotubes are key to success. The catalyst was synthesized using an ionic liquid, which is responsible for the stabilization of the Fe ions. The polymerization of the ionic liquid leads to an entangling around the carbon nanotube support, thus creating a very stable compound. In aspiration to understand the observed regioselectivity of this catalyst, it was investigated utilizing a wide range of experimental methods (STEM, TEM, NEXAFS, XPS) and supported with theoretical work.
This work has brought some new perspectives in understanding the role of iron species in selective oxidation reactions. Furthermore, the insights into the correlation of the catalytic behavior of iron species with the coordinated environment will advance future design of highly selective and efficient iron-based heterogeneous catalysts.
The importance of this finding was recognized by the editorial board of the Green Chemistry journal and therefore highlighted as inside back cover of the current issue.
Original publication: Ding, Y., Zhang, P., Xiong, H., Sun, X., Klyushin, A., Zhang, B., Liu, Z., Zhang, J., Zhu, H., Xiao, Z.-A., Heumann, S., Dai, S. (2020). Tuning Regioselective Oxidation toward Phenol via Atomically Dispersed Iron Sites on Carbon Green Chemistry https://doi.org/10.1039/D0GC01717E