Fe doped aluminoborate PKU-1 catalysts for the ketalization of glycerol to solketal: Unveiling the effects of iron composition and boron

An inexpensive Fe doped aluminoborate consisted of 18% Fe in PKU-1 material that exhibits high selectivity of 4-hydroxymethy-2,2-dimethyl-1,3-dioxolane (Solketal, 98.3%), considerable activity (TOF 51.7 h(-1)), and recyclable ability in the ketalization of glycerol to Solketal with acetone at 318 K has been developed. Our study demonstrated that the structure of Fe (less agglomerated iron species vs. FeOx clusters) can be tuned by changing Fe loading in the PKU-1 material, which correlated well with experimental observations. Furthermore, the surface boron sites were promoted by iron loading and behaved as Lewis-acid sites to facilitate the reaction process of glycerol ketalization, while the Solketal selectivity was closely related with the structure of iron species in PKU-1, which was proved by kinetic studies, density function theory (DFT) calculations, and a series of spectroscopy studies. This investigation demonstrates that the surface B sites can play important roles in the reaction instead of being spectators. (C) 2021 Published by Elsevier B.V. on behalf of Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences.

Automated summary

An inexpensive Fe doped aluminoborate material with high selectivity and recyclability has been developed for the ketalization of glycerol. The structure of iron species and surface boron sites play crucial roles in the reaction process. Changing the iron loading can tune the structure of iron species in the material, thereby affecting the selectivity of the reaction.