Understanding how the crystalline nature of Fe-promoted alumino-borate PKU-1 catalyst affects Glycerin ketalization: The systematic control of surface composition and acidity

A series of Fe-doped alumino-borate catalysts (18 % Fe-PKU-1) with a range of crystalline qualities has been obtained by varying synthesis conditions. Based on Angle-resolved X-ray Photoelectron Spectroscopy, pyridine adsorption infrared spectroscopy, and potentiometric titration, crystalline quality is correlated as volcano trends with the surface composition and electronic structure of Fe-PKU-1, especially for the boron species. Through the systematic change of synthesized conditions, the catalyst with the appropriate crystalline quality shows the highest surface compositions of boron and oxygen vacancies. This leads to strong surface Lewis acidity and results in the high catalytic performance of glycerin ketalization, 97 % conversion and 99 % selectivity in DL-1,2-Isopropylideneglycerol (Solketal).