Methane dehydroaromatization over modified Mn/H-ZSM-5 zeolite catalysts: Effect of tungsten as a secondary metal

2016 ◽  
Vol 78 ◽  
pp. 37-43 ◽  
Author(s):  
Themba E. Tshabalala ◽  
Neil J. Coville ◽  
Michael S. Scurrell
Keyword(s):  
Zeolite Catalysts ◽  
Methane Dehydroaromatization

ChemInform Abstract: Metal/Zeolite Catalysts of Methane Dehydroaromatization

ChemInform ◽  
2014 ◽  
Vol 45 (38) ◽  
pp. no-no
Author(s):  
N. A. Mamonov ◽  
E. V. Fadeeva ◽  
D. A. Grigoriev ◽  
M. N. Mikhailov ◽  
L. M. Kustov ◽  
...  
Keyword(s):  
Zeolite Catalysts ◽  
Methane Dehydroaromatization

scholarly journals Acidic and Catalytic Properties of Mo-Containing Zeolite Catalysts for Non-Oxidative Methane Conversion

2017 ◽  
Vol 6 (3) ◽  
pp. 201 ◽  
Author(s):  
A.V. Vosmerikov ◽  
G.V. Echevsky ◽  
L.L. Korobitsyna ◽  
N.V. Arbuzova ◽  
L.M. Velichkina ◽  
...  
Keyword(s):  
Induction Period ◽  
Methane Conversion ◽  
Space Velocity ◽  
Zeolite Catalysts ◽  
Mechanical Mixing ◽  
Ammonium Heptamolybdate ◽  
Methane Dehydroaromatization ◽  
Conversion Of Methane ◽  
Benzene Toluene ◽  
The Stability

<p>The conversion of methane into benzene, toluene and naphthalene at the reaction temperature of 750 °C and gas hourly space velocity (GHSV) of 500-1500 h<sup>-1</sup> over zeolites modified via impregnation with ammonium heptamolybdate and mechanical mixing with Mo oxide and nanopowder is studied under non-oxidative conditions. It has been established that the highest methane conversion per one run and maximal yield of aromatic hydrocarbons are reached for the sample containing 4.0 mass.% the Mo nanopowder. The stability of Mo-containing zeolite catalysts in the process of methane dehydroaromatization at different GHSV has been studied and a characteristic presence of the induction period caused by the formation of active Mo forms both on the external surface and into the zeolite channels has been established. Both the duration of induction period and stable catalyst operation are decreasing with increasing of GHSV. It was demonstrated that acidic properties of a Mo-containing zeolite catalyst depend on the Mo concentration and method of its introduction.</p>

scholarly journals Resistance against Carbon Deposition via Controlling Spatial Distance of Catalytic Components in Methane Dehydroaromatization

Catalysts ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 148
Author(s):  
Yan Zeng ◽  
Ayano Kimura ◽  
Peipei Zhang ◽  
Jiaming Liang ◽  
Jiaqi Fan ◽  
...  
Keyword(s):  
Mechanical Milling ◽  
High Selectivity ◽  
Carbon Deposition ◽  
Zeolite Catalysts ◽  
Spatial Distance ◽  
Product Selectivity ◽  
Active Components ◽  
Methane Dehydroaromatization

Molybdenum-zeolite catalysts always suffer from severe carbon deposition and rapid deactivation in the methane dehydroaromatization (MDA) process. Herein, we present a strategy that controls spatial distance between Mo species and HMCM-22 zeolite over Mo/HMCM-22 catalysts, to inhibit the severe carbon deposition. Our characterization analyses demonstrate that the Mo/HMCM-22 catalysts possess the same active components, but the spatial distance plays a key role in determining product selectivity in the MDA process. The MDA performance reveals that Mo/HMCM-22-MM (mechanical milling) catalyst, with a medium spatial distance between Mo species and HMCM-22 zeolite, significantly inhibits carbon deposition and produces high selectivity to benzene. This work shows that spatial distance between molybdenum and zeolite is an important property for suppressing carbon deposition and improving benzene selectivity in MDA process.

Metal/zeolite catalysts of methane dehydroaromatization

2013 ◽  
Vol 82 (6) ◽  
pp. 567-585 ◽  
Author(s):  
N A Mamonov ◽  
E V Fadeeva ◽  
D A Grigoriev ◽  
M N Mikhailov ◽  
Leonid M Kustov ◽  
...  
Keyword(s):  
Zeolite Catalysts ◽  
Methane Dehydroaromatization

Advances in ultramicrotomy for physical sciences applications

1993 ◽  
Vol 51 ◽  
pp. 710-711
Author(s):  
G. McMahon ◽  
T. Malis
Keyword(s):  
Particle Surface ◽  
Zeolite Catalysts ◽  
Physical Sciences ◽  
Pull Out ◽  
Large Particles ◽  
Novel Applications ◽  
Metal Wires ◽  
Frequent Problem ◽  
Specific Orientation ◽  
Diamond Knife

As with all techniques which are relatively new and therefore underutilized, diamond knife sectioning in the physical sciences continues to see both developments of the technique and novel applications.Technique Developments Development of specific orientation/embedding procedures for small pieces of awkward shape is exemplified by the work of Bradley et al on large, rather fragile particles of nuclear waste glass. At the same time, the frequent problem of pullout with large particles can be reduced by roughening of the particle surface, and a proven methodology using a commercial coupling agent developed for glasses has been utilized with good results on large zeolite catalysts. The same principle (using acid etches) should work for ceramic fibres or metal wires which may only partially pull out but result in unacceptably thick sections. Researchers from the life sciences continue to develop aspects of embedding media which may be applicable to certain cases in the physical sciences.

Methane activation by ZSM-5-supported transition metal centers

2021 ◽  
Author(s):  
Daniyal Kiani ◽  
Sagar Sourav ◽  
Yadan Tang ◽  
Jonas Baltrusaitis ◽  
Israel E. Wachs
Keyword(s):  
Transition Metal ◽  
Methane Activation ◽  
Group V ◽  
Metal Centers ◽  
Methane Dehydroaromatization

The literature on methane dehydroaromatization (MDA) to benzene using ZSM-5 supported, group V–VIII transition metal-based catalysts (MOx/ZSM-5) is critically reviewed with a focus on in situ and operando molecular insights.

Effect of Ethane Addition on Methane Dehydroaromatization over Mo/HZSM-5 Catalyst

2010 ◽  
Vol 31 (1) ◽  
pp. 78-83
Author(s):  
Changyong SUN ◽  
Songdong YAO ◽  
Wenjie SHEN ◽  
Liwu LIN
Keyword(s):  
Methane Dehydroaromatization

Performance of Ag-HZSM-5 Zeolite Catalysts in n-heptane Conversion

2017 ◽  
Vol 68 (1) ◽  
pp. 116-120
Author(s):  
Iuliean Vasile Asaftei ◽  
Neculai Catalin Lungu ◽  
Lucian Mihail Birsa ◽  
Ioan Gabriel Sandu ◽  
Laura Gabriela Sarbu ◽  
...  
Keyword(s):  
Aromatic Hydrocarbons ◽  
Metal Content ◽  
Pulse Method ◽  
Acid Strength ◽  
Strength Distribution ◽  
Zeolite Catalysts ◽  
Benzene Toluene ◽  
Acid Strength Distribution ◽  
Silver Cations ◽  
Heptane Conversion

The conversion of n-heptanes into aromatic hydrocarbons benzene, toluene and xylenes (BTX), by the chromatographic pulse method in the temperature range of 673 - 823K was performed over the HZSM-5 and Ag-HZSM-5 zeolites modified by ion exchange with AgNO3 aqueous solutions. The catalysts, HZSM-5 (SiO2/Al2O3 = 33.9), and Ag-HZSM-5 (Ag1-HZSM-5 wt. % Ag1.02, Ag2-HZSM-5 wt. % Ag 1.62; and Ag3-HZSM-5 wt. % Ag 2.05 having different acid strength distribution exhibit a conversion and a yield of aromatics depending on temperature and metal content. The yield of aromatic hydrocarbons BTX appreciably increased by incorporating silver cations Ag+ into HZSM-5.

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