Investigation of the catalytic activity of niobium phosphates for liquid phase alkylation of anisole with benzyl chloride

In this work crystalline niobium phosphate with different degrees of crystallinity was synthesized by two different methods as catalysts for benzylation of anisole with benzyl chloride. The catalysts were characterized by XRD, N2 physisorption, solid state 31P and 93Nb NMR, structural FTIR and FTIR after adsorption of pyridine. The catalytic activities were measured in the benzylation of anisole with benzyl chloride. The NMR technique seems to be more sensitive in evaluating the presence of amorphous phase, compared with DRX data. The crystalline niobium phosphate prepared by recrystallization of a commercial sample presented activity comparable to its parent compound, in contrast with the crystalline catalyst prepared from niobic acid. The activity was attributed to the Lewis sites present mostly on the amorphous phase of the catalysts.

Figure optionsDownload high-quality image (44 K)Download as PowerPoint slideResearch highlights▶ 31P and 93Nb solid state NMR proved to be more sensitive in evaluating the presence of different phases in niobium phosphate compared with DRX. ▶ High catalytic activity of niobium phosphate for benzylation of anisole with benzyl chloride. ▶ It can be noticed that crystalline Nb-P is also active for reactions promoted by Lewis acid sites.