Enhancement of catalytic properties and lifetime of nanostructured SAPO-34 by La isomorphous substitution and alteration of Si/Al ratio used in methanol conversion to light olefins

RSC Advances ◽  
2016 ◽  
Vol 6 (56) ◽  
pp. 51024-51036 ◽  
Author(s):  
Abolfazl Amoozegar ◽  
Mohammad Haghighi ◽  
Sogand Aghamohammadi
Keyword(s):  
Catalytic Properties ◽  
Methanol Conversion ◽  
Light Olefins ◽  
Isomorphous Substitution

Methanol conversion to light olefins was investigated over SAPO-34 catalysts with La introduction exploring the effect of different Si/Al ratios.

Structural/Texture Evolution During Facile Substitution of Ni into ZSM-5 Nanostructure vs. its Impregnation Dispersion Used in Selective Transformation of Methanol to Ethylene and Propylene

2020 ◽  
Vol 23 ◽  
Author(s):  
Parisa Sadeghpour ◽  
Mohammad Haghighi ◽  
Mehrdad Esmaeili
Keyword(s):  
High Temperature ◽  
Physicochemical Properties ◽  
Active Sites ◽  
Catalytic Performance ◽  
Fixed Bed Reactor ◽  
Light Olefins ◽  
Isomorphous Substitution ◽  
Impregnation Method ◽  
Hydrothermal Temperature ◽  
X Ray

Aim and Objective: Effect of two different modification methods for introducing Ni into ZSM-5 framework was investigated under high temperature synthesis conditions. The nickel successfully introduced into the MFI structures at different crystallization conditions to enhance the physicochemical properties and catalytic performance. Materials and Methods: A series of impregnated Ni/ZSM-5 and isomorphous substituted NiZSM-5 nanostructure catalysts were prepared hydrothermally at different high temperatures and within short times. X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), Energy dispersive X-ray (EDX), Brunner, Emmett and Teller-Barrett, Joyner and Halenda (BET-BJH), Fourier transform infrared (FTIR) and Temperature-programmed desorption of ammonia (TPDNH3) were applied to investigate the physicochemical properties. Results: Although all the catalysts showed pure silica MFI–type nanosheets and coffin-like morphology, using the isomorphous substitution for Ni incorporation into the ZSM-5 framework led to the formation of materials with lower crystallinity, higher pore volume and stronger acidity compared to using impregnation method. Moreover, it was found that raising the hydrothermal temperature increased the crystallinity and enhanced more uniform incorporation of Ni atoms in the crystalline structure of catalysts. TPD-NH3 analysis demonstrated that high crystallization temperature and short crystallization time of NiZSM-5(350-0.5) resulted in fewer weak acid sites and medium acid strength. The MTO catalytic performance was tested in a fixed bed reactor at 460ºC and GHSV=10500 cm3 /gcat.h. A slightly different reaction pathway was proposed for the production of light olefins over impregnated Ni/ZSM-5 catalysts based on the role of NiO species. The enhanced methanol conversion for isomorphous substituted NiZSM-5 catalysts could be related to the most accessible active sites located inside the pores. Conclusion: The impregnated Ni/ZSM-5 catalyst prepared at low hydrothermal temperature showed the best catalytic performance, while the isomorphous substituted NiZSM-5 prepared at high temperature was found to be the active molecular sieve regarding the stability performance.

scholarly journals Control of zeolite microenvironment for propene synthesis from methanol

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Longfei Lin ◽  
Mengtian Fan ◽  
Alena M. Sheveleva ◽  
Xue Han ◽  
Zhimou Tang ◽  
...  
Keyword(s):  
Active Sites ◽  
Inelastic Neutron Scattering ◽  
Sustainable Manufacturing ◽  
Methanol Conversion ◽  
Acid Sites ◽  
Light Olefins ◽  
Carbon Bond ◽  
X Ray ◽  
Carbon Carbon Bond ◽  
Catalytic Stability

AbstractOptimising the balance between propene selectivity, propene/ethene ratio and catalytic stability and unravelling the explicit mechanism on formation of the first carbon–carbon bond are challenging goals of great importance in state-of-the-art methanol-to-olefin (MTO) research. We report a strategy to finely control the nature of active sites within the pores of commercial MFI-zeolites by incorporating tantalum(V) and aluminium(III) centres into the framework. The resultant TaAlS-1 zeolite exhibits simultaneously remarkable propene selectivity (51%), propene/ethene ratio (8.3) and catalytic stability (>50 h) at full methanol conversion. In situ synchrotron X-ray powder diffraction, X-ray absorption spectroscopy and inelastic neutron scattering coupled with DFT calculations reveal that the first carbon–carbon bond is formed between an activated methanol molecule and a trimethyloxonium intermediate. The unprecedented cooperativity between tantalum(V) and Brønsted acid sites creates an optimal microenvironment for efficient conversion of methanol and thus greatly promotes the application of zeolites in the sustainable manufacturing of light olefins.

Effect of magnesium on the catalytic properties of polymetallic zeolite catalysts for conversion of dimethyl ether to light olefins

2020 ◽  
Vol 298 ◽  
pp. 110087 ◽  
Author(s):  
N.V. Kolesnichenko ◽  
Е.N. Khivrich ◽  
T.K. Obukhova ◽  
Т.I. Batova ◽  
G.N. Bondarenko
Keyword(s):  
Dimethyl Ether ◽  
Catalytic Properties ◽  
Zeolite Catalysts ◽  
Light Olefins

Methanol Conversion to Light Olefins over SAPO-34. Sorption, Diffusion, and Catalytic Reactions

1999 ◽  
Vol 38 (11) ◽  
pp. 4241-4249 ◽  
Author(s):  
D. Chen ◽  
H. P. Rebo ◽  
K. Moljord ◽  
A. Holmen
Keyword(s):  
Methanol Conversion ◽  
Catalytic Reactions ◽  
Light Olefins

Methanol conversion on silica-aluminas. Production of light olefins

1991 ◽  
Vol 44 (1) ◽  
pp. 133-138
Author(s):  
U. A. Sedran ◽  
N. S. Fígoli
Keyword(s):  
Methanol Conversion ◽  
Light Olefins

Behaviors of coke deposition on SAPO-34 catalyst during methanol conversion to light olefins

2007 ◽  
Vol 88 (5) ◽  
pp. 437-441 ◽  
Author(s):  
Guozhen Qi ◽  
Zaiku Xie ◽  
Weimin Yang ◽  
Siqing Zhong ◽  
Hongxing Liu ◽  
...  
Keyword(s):  
Methanol Conversion ◽  
Coke Deposition ◽  
Light Olefins
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