The promoting role of silver on the supported silver salt of dodecatungstosiliticic acid in the methanol-to-hydrocarbon conversion

1987 ◽  
Vol 35 (1-2) ◽  
pp. 173-184 ◽  
Author(s):  
G. Öhlmann ◽  
H. Ehwald ◽  
V. S. Musykantov
Keyword(s):  
Silver Salt ◽  
Hydrocarbon Conversion ◽  
Methanol To Hydrocarbon

scholarly journals Palladium-catalyzed Suzuki-Miyaura coupling of thioureas or thioamides

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Shaoyu Mai ◽  
Wendong Li ◽  
Xue Li ◽  
Yingwei Zhao ◽  
Qiuling Song
Keyword(s):  
Silver Salt ◽  
Coupling Reaction ◽  
Coupling Reactions ◽  
Mechanistic Studies ◽  
Aromatic Rings ◽  
Cross Coupling Reactions ◽  
Broad Array ◽  
Palladium Catalyzed

AbstractCross-coupling reactions involving metal carbene intermediates play an increasingly important role in C–C bond formation. Expanding the carbene precursors to a broader range of starting materials and more diverse products is an ongoing challenge in synthetic organic chemistry. Herein, we report a Suzuki-Miyaura coupling reaction of in situ-generated Pd–carbene complexes via desulfurization of thioureas or thioamides. This strategy enables the preparation of a broad array of substituted amidinium salts and unsymmetrical diaryl ketones. The reaction is readily scalable, compatible with bromo groups on aromatic rings, tolerant to moisture and air and has a broad substrate scope. Furthermore, a single crystal structure of Pd-diaminocarbene complex is obtained and proven to be the key intermediate in both catalytic and stoichiometric reactions. Preliminary mechanistic studies demonstrate the dual role of the silver salt as a desulfurating reagent assisting the elimination of sulfur and as oxidant facilitating the PdII/Pd0/PdII catalytic cycle.

A computational study of methanol-to-hydrocarbon conversion — Towards the design of a low-barrier process

2010 ◽  
Vol 88 (8) ◽  
pp. 866-876 ◽  
Author(s):  
Bun Chan ◽  
Leo Radom
Keyword(s):  
Quantum Chemistry ◽  
Computational Study ◽  
Carbon Pool ◽  
Low Energy ◽  
Zeolite Catalysts ◽  
Hydrocarbon Conversion ◽  
Aromatic Carbon ◽  
Computational Quantum Chemistry ◽  
Methanol To Hydrocarbon ◽  
Computational Quantum

Computational quantum chemistry has been employed to examine the production of ethylene with methanol-to-hydrocarbon (MTH) processes via a carbon pool mechanism. We find that the M05-2X functional performs well for the types of reactions that are involved. The methylation reactions of the aromatic cocatalyst are the most energy-demanding steps in the process. For the subsequent production of C2H4, we have identified a low-energy pathway that involves multiple methyl shifts, followed by concerted deprotonation and C2H4 elimination. The substitutions of the Al and Si atoms in the participating Si–OH–Al moiety of zeolite catalysts with Ga and Ge do not lead to lower barriers for the methylation reactions, nor does the use of a more electron-rich aromatic cocatalyst. However, we find that the use of two cocatalysts, a nucleophile and an aromatic carbon pool, can provide an overall low-energy pathway for the MTH process.

scholarly journals Surface enhanced dynamic nuclear polarization solid-state NMR spectroscopy sheds light on Brønsted–Lewis acid synergy during the zeolite catalyzed methanol-to-hydrocarbon process

2019 ◽  
Vol 10 (39) ◽  
pp. 8946-8954 ◽  
Author(s):  
Abhishek Dutta Chowdhury ◽  
Irina Yarulina ◽  
Edy Abou-Hamad ◽  
Andrei Gurinov ◽  
Jorge Gascon
Keyword(s):  
Solid State ◽  
Nmr Spectroscopy ◽  
Lewis Acid ◽  
Dynamic Nuclear Polarization ◽  
Solid State Nmr ◽  
Nuclear Polarization ◽  
Solid State Nmr Spectroscopy ◽  
Surface Enhanced ◽  
Methanol To Hydrocarbon

Surface-enhanced dynamic nuclear polarization solid-state NMR spectroscopy has been applied to identify the role of surface-carbene species and elucidating Brønsted–Lewis acid synergy during the zeolite-catalyzed methanol-to-hydrocarbon process.

π‐Interactions between Cyclic Carbocations and Aromatics Cause Zeolite Deactivation in Methanol‐to‐Hydrocarbon Conversion

2020 ◽  
Vol 59 (18) ◽  
pp. 7198-7202 ◽  
Author(s):  
Chao Wang ◽  
Min Hu ◽  
Yueying Chu ◽  
Xue Zhou ◽  
Qiang Wang ◽  
...  
Keyword(s):  
Hydrocarbon Conversion ◽  
Π Interactions ◽  
Methanol To Hydrocarbon

scholarly journals Effects of crystal size on methanol to hydrocarbon conversion over single crystals of ZSM-5 studied by synchrotron infrared microspectroscopy

2020 ◽  
Vol 22 (34) ◽  
pp. 18849-18859
Author(s):  
Ivalina B. Minova ◽  
Santhosh K. Matam ◽  
Alex Greenaway ◽  
C. Richard A. Catlow ◽  
Mark D. Frogley ◽  
...  
Keyword(s):  
Induction Period ◽  
Single Crystals ◽  
Crystal Size ◽  
Hydrocarbon Conversion ◽  
Infrared Microspectroscopy ◽  
Hydrocarbon Pool ◽  
Methanol To Hydrocarbon ◽  
Increasing Temperature

The induction period for alkene formation from methanol in single crystals of HZSM-5 decreases with decreasing crystal size and increasing temperature and hydrocarbon pool species are formed almost instantaneously at higher temperatures.

π‐Interactions between Cyclic Carbocations and Aromatics Cause Zeolite Deactivation in Methanol‐to‐Hydrocarbon Conversion

2020 ◽  
Vol 132 (18) ◽  
pp. 7265-7269 ◽  
Author(s):  
Chao Wang ◽  
Min Hu ◽  
Yueying Chu ◽  
Xue Zhou ◽  
Qiang Wang ◽  
...  
Keyword(s):  
Hydrocarbon Conversion ◽  
Π Interactions ◽  
Methanol To Hydrocarbon
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