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Effect of boron on ZSM-5 catalyst for methanol to propylene conversion

100%

Xu A. , Ma H. , Zhang H. , Weiyong D. , Fang D.

Polish Journal of Chemical Technology

2013

tom 15

nr 4

95-101

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.

Density Functional Calculations on the Adsorption of N2O and H2O on the Ion-ex changed ZSM-5

88%

Gao H. W. , Guo L. , Deng H. H. , Ge L. Y. , Yan T. X.

2009

tom Vol. 83, nr 6

1195-1201

Density functional theory (DFT) calculations were performed to study the configuration and electronic states of N2O and H2O adsorbed on the ion-ex changed ZSM-5 using the Gaussian98 program. We also calculated the adsorption energy of NO2 species and H2O ad sorbed on various ion exchanged ZSM-5. The calculated results indicated that Cu+, Co2+ and Ti3+ sites on ZSM-5 have strong affinity to N2O and these metal cations are stable against water poisoning.

Influence of heteropoly acid and USY zeolite on activity of ZSM-5 containing catalysts.

75%

Grzechowiak J. R. , Masalska A.

tom Vol. 10, nr 57

343-348

Activity and selectivity of Ni/ZSM-5+Al2O3 catalyst (8 wt.% NiO) containing 30 wt.% Ni,H-ZSM-5 were compared to those of catalysts to which USY zeolite, Ni,H-ZSM-5 zeolite, and heteropoly acid were added (20%). The ZSM-5 containing catalyst modified with heteropoly acid was less active than those modified by zeolite (USY, ZSM-5). N-Hexane conversion was highest for the catalyst contg. 50 wt.% zeolite. The yield of hydrocracking products was higher for the catalyst contg. 50 wt.% ZSM-5 than that of catalyst containing 30 wt.% ZSM-5 and 20 wt.% USY zeolites. Modification of the ZSM-5 containing catalyst did not result in higher yield of isomerization products.