B-ZSM-5 catalysts were prepared by various modification methods with boric acid, including ion-exchange, impregnation and direct synthesis. The catalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), NH3-Temperature Programmed Desorption (NH3-TPD), N2 adsorption-desorption, Fourier Transform Infrared spectrometry (FT-IR), 27Al and 11B MAS NMR spectra. The results revealed that the weak acidity of catalysts was significantly increased by modification. The catalytic activity was measured in a fixed bed at 460°C for methanol to propylene (MTP) reaction. The results of MTP reaction showed a great increment of the propylene selectivity for the boron modified samples, especially for the directly synthesized B-ZSM-5 which also displayed high activity and selectivity towards C2 =-C4 = olefins. It was found that the remarkable selectivity strongly depended on the intensity of weak acidity.
JavaScript is turned off in your web browser. Turn it on to take full advantage of this site, then refresh the page.