Insight into the active site and reaction mechanism for selective oxidation of methane to methanol using H2O2 on a Rh1/ZrO2 catalyst

2020 ◽  
Vol 44 (4) ◽  
pp. 1632-1639 ◽  
Author(s):  
Qi Zhao ◽  
Bing Liu ◽  
Yuebing Xu ◽  
Feng Jiang ◽  
Xiaohao Liu
Keyword(s):  
Reaction Mechanism ◽  
Selective Oxidation ◽  
Active Site ◽  
Oxidation Of Methane ◽  
Methanol Formation ◽  
Zro2 Catalyst ◽  
Insight Into

Five-coordinated Rh leads to the over-oxidation of CH4, while four-coordinated Rh stabilizes CH3 and facilitates methanol formation via the CH3OOH intermediate.

The crystal structure of human mitochondrial 3-ketoacyl-CoA thiolase (T1): insight into the reaction mechanism of its thiolase and thioesterase activities

2014 ◽  
Vol 70 (12) ◽  
pp. 3212-3225 ◽  
Author(s):  
Tiila-Riikka Kiema ◽  
Rajesh K. Harijan ◽  
Malgorzata Strozyk ◽  
Toshiyuki Fukao ◽  
Stefan E. H. Alexson ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Reaction Mechanism ◽  
Active Site ◽  
Quaternary Structure ◽  
Fatty Acyl ◽  
Physiological Importance ◽  
Loop Domain ◽  
Solution Studies ◽  
Hydrolysis Of ◽  
Insight Into

Crystal structures of human mitochondrial 3-ketoacyl-CoA thiolase (hT1) in the apo form and in complex with CoA have been determined at 2.0 Å resolution. The structures confirm the tetrameric quaternary structure of this degradative thiolase. The active site is surprisingly similar to the active site of theZoogloea ramigerabiosynthetic tetrameric thiolase (PDB entries 1dm3 and 1m1o) and different from the active site of the peroxisomal dimeric degradative thiolase (PDB entries 1afw and 2iik). A cavity analysis suggests a mode of binding for the fatty-acyl tail in a tunnel lined by the Nβ2–Nα2 loop of the adjacent subunit and the Lα1 helix of the loop domain. Soaking of the apo hT1 crystals with octanoyl-CoA resulted in a crystal structure in complex with CoA owing to the intrinsic acyl-CoA thioesterase activity of hT1. Solution studies confirm that hT1 has low acyl-CoA thioesterase activity for fatty acyl-CoA substrates. The fastest rate is observed for the hydrolysis of butyryl-CoA. It is also shown that T1 has significant biosynthetic thiolase activity, which is predicted to be of physiological importance.

Selective oxidation of methane in the presence of nitric oxide: comments on the reaction mechanism

1990 ◽  
Vol 6 (4) ◽  
pp. 399-407 ◽  
Author(s):  
Graham J. Hutchings ◽  
Michael S. Scurrell ◽  
Jeremy R. Woodhouse
Keyword(s):  
Nitric Oxide ◽  
Reaction Mechanism ◽  
Selective Oxidation ◽  
Oxidation Of Methane

scholarly journals The metal centres of particulate methane mono-oxygenase

2008 ◽  
Vol 36 (6) ◽  
pp. 1134-1137 ◽  
Author(s):  
Amy C. Rosenzweig
Keyword(s):  
Crystal Structure ◽  
Reaction Mechanism ◽  
Structure Determination ◽  
Active Site ◽  
Spectroscopic Data ◽  
Present Review ◽  
Methylococcus Capsulatus ◽  
Research Groups ◽  
Oxidation Of Methane ◽  
Before And After

pMMO (particulate methane mono-oxygenase) is an integral membrane metalloenzyme that catalyses the oxidation of methane to methanol. The pMMO metal active site has not been identified, precluding detailed investigation of the reaction mechanism. Models for the metal centres proposed by various research groups have evolved as crystallographic and spectroscopic data have become available. The present review traces the evolution of these active-site models before and after the 2005 Methylococcus capsulatus (Bath) pMMO crystal structure determination.

Selective oxidation of methane and its homologues to alcohols catalyzed by gold compounds and a proposed reaction mechanism

2010 ◽  
Vol 430 (2) ◽  
pp. 50-53 ◽  
Author(s):  
L. A. Levchenko ◽  
N. G. Lobanova ◽  
V. M. Martynenko ◽  
A. P. Sadkov ◽  
A. F. Shestakov ◽  
...  
Keyword(s):  
Reaction Mechanism ◽  
Selective Oxidation ◽  
Oxidation Of Methane ◽  
Gold Compounds

A proposed reaction mechanism for the selective oxidation of methane with nitrous oxide over Co-ZSM-5 catalyst forming synthesis gas (CO + H2)

2018 ◽  
Vol 43 (29) ◽  
pp. 13133-13144 ◽  
Author(s):  
Naseer A. Khan ◽  
Eric M. Kennedy ◽  
Bogdan Z. Dlugogorski ◽  
Adesoji A. Adesina ◽  
Michael Stockenhuber
Keyword(s):  
Nitrous Oxide ◽  
Reaction Mechanism ◽  
Selective Oxidation ◽  
Synthesis Gas ◽  
Oxidation Of Methane

scholarly journals Cation-exchanged zeolites for the selective oxidation of methane to methanol

2018 ◽  
Vol 8 (1) ◽  
pp. 114-123 ◽  
Author(s):  
Ambarish R. Kulkarni ◽  
Zhi-Jian Zhao ◽  
Samira Siahrostami ◽  
Jens K. Nørskov ◽  
Felix Studt
Keyword(s):  
Transition Metal ◽  
Selective Oxidation ◽  
Metal Cation ◽  
Active Site ◽  
Methane Activation ◽  
Transition Metal Cation ◽  
Trade Off ◽  
Oxidation Of Methane ◽  
Active Site Motif

Development of an ideal methane activation catalyst presents a trade-off between stability and reactivity of the active site that can be achieved by tuning the transition metal cation, active site motif and the zeolite topology.

scholarly journals Approaches for Selective Oxidation of Methane to Methanol

Catalysts ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 194 ◽  
Author(s):  
Richa Sharma ◽  
Hilde Poelman ◽  
Guy B. Marin ◽  
Vladimir V. Galvita
Keyword(s):  
Selective Oxidation ◽  
Active Site ◽  
Density Functional ◽  
Spectroscopic Studies ◽  
Methane Activation ◽  
Chemical Looping ◽  
Intermediate Species ◽  
Functional Theory ◽  
Oxidation Of Methane ◽  
Industrial Standards

Methane activation chemistry, despite being widely reported in literature, remains to date a subject of debate. The challenges in this reaction are not limited to methane activation but extend to stabilization of the intermediate species. The low C-H dissociation energy of intermediates vs. reactants leads to CO2 formation. For selective oxidation, nature presents methane monooxygenase as a benchmark. This enzyme selectively consumes methane by breaking it down into methanol. To assemble an active site similar to monooxygenase, the literature reports Cu-ZSM-5, Fe-ZSM-5, and Cu-MOR, using zeolites and systems like CeO2/Cu2O/Cu. However, the trade-off between methane activation and methanol selectivity remains a challenge. Density functional theory (DFT) calculations and spectroscopic studies indicate catalyst reducibility, oxygen mobility, and water as co-feed as primary factors that can assist in enabling higher selectivity. The use of chemical looping can further improve selectivity. However, in all systems, improvements in productivity per cycle are required in order to meet the economical/industrial standards.

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