Catalysis and deactivation of montmorillonite K10 in the aryl O -glycosylation of glycosyl trichloroacetoimidates

Abstract

The catalysis of montmorillonite K10 (MK10) for aryl O-glycosylation of glycosyl trichloroacetimidates was investigated. It was found that the catalyst MK10 is deactivated gradually in the recycle glycosylation. The fresh and the deactivated catalysts were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Thermogravimetric analysis (TGA), and N₂ adsorption-desorption. The results show that the eliminated trichloroacetamide molecule deposits on the MK10, which blocks and poisons the active sites, resulting in the deactivation of the catalyst. The regeneration of the deactivated MK10 by calcination was studied preliminarily.