Mechanistic study on –C–O– and –C–C– hydrogenolysis over Cu catalysts: identification of reaction pathways and key intermediates

2018 ◽  
Vol 8 (3) ◽  
pp. 755-767 ◽  
Author(s):  
Benjamin Kühne ◽  
Herbert Vogel ◽  
Reinhard Meusinger ◽  
Sebastian Kunz ◽  
Markwart Kunz
Keyword(s):  
Catalyst Surface ◽  
Bond Cleavage ◽  
Chelate Complex ◽  
Reaction Pathways ◽  
Mechanistic Study ◽  
Side Reactions ◽  
Sugar Alcohols ◽  
Oh Groups ◽  
Surface Yield ◽  
Cu Catalysts

Sugar alcohols are found to adsorb over Cu catalysts via two vicinal OH-groups, forming a chelate complex with selective –C–O– bond cleavage of adjacent free OH-groups. Different side reactions via unsaturated intermediates on the catalyst surface yield C1 to C5 polyols.

Hydrogenation-dehydrogenation and cleavage functions of hydrorefining catalysts studied by the reaction of tetrahydrothiophene

1986 ◽  
Vol 51 (12) ◽  
pp. 2770-2780 ◽  
Author(s):  
Alexandra Drahorádová ◽  
Miroslav Zdražil
Keyword(s):  
Activated Carbon ◽  
Catalyst Surface ◽  
Bond Cleavage ◽  
Unsaturated Hydrocarbons ◽  
Cleavage Reactions

The reaction of tetrahydrothiophene in a stream of nitrogen was used to study the relations between dehydrogenation and C-S cleavage reactions on sulphided Co-Mo/Al2O3 catalysts. The course of the reaction was compared for Co-Mo catalysts supported on alumina and activated carbon, for alumina alone as well as for a Pt/C catalyst. The effect of substitution of nitrogen for hydrogen, of the addition of water to the feed, of pre-sulphidation of catalysts and their deactivation by coking on the rate and selectivity of the reaction were also investigated. The results showed that hydrogenation-dehydrogenation and dehydrosulphurization activity of the sulphide catalysts have the same origin. Hydrogen accelerates dehydrosulphurization on the sulphide catalysts by removing sulphur and unsaturated hydrocarbons formed on catalyst surface by C-S bond cleavage reactions.

Regiochemical Selectivity in the Carbon-Sulfur Bond Cleavage of 2-Methylbenzothiophene: Synthesis, Characterization, and Mechanistic Study of Reversible Insertion into a C-S Bond

1995 ◽  
Vol 117 (47) ◽  
pp. 11704-11709 ◽  
Author(s):  
Andrew W. Myers ◽  
William D. Jones ◽  
Shawn M. McClements
Keyword(s):  
Bond Cleavage ◽  
Mechanistic Study ◽  
Sulfur Bond

A Mechanistic Study of Trichoderma reesei Cel7B Catalyzed Glycosidic Bond Cleavage

2013 ◽  
Vol 117 (29) ◽  
pp. 8714-8722 ◽  
Author(s):  
Yu Zhang ◽  
Shihai Yan ◽  
Lishan Yao
Keyword(s):  
Trichoderma Reesei ◽  
Bond Cleavage ◽  
Glycosidic Bond ◽  
Mechanistic Study ◽  
Glycosidic Bond Cleavage

Mechanisms of Electrochemical N2 Splitting by a Molybdenum Pincer Complex

2021 ◽  
Author(s):  
Quinton Bruch ◽  
Santanu Malakar ◽  
Alan Goldman ◽  
Alexander Miller
Keyword(s):  
Electrode Surface ◽  
Redox Reactions ◽  
Catalytic Reduction ◽  
Reaction Pathways ◽  
Bulk Solution ◽  
Mechanistic Study ◽  
Pincer Ligands ◽  
Computational Studies ◽  
Pincer Complex ◽  
Bond Scission

Molybdenum complexes supported by tridentate pincer ligands are exceptional catalysts for dinitrogen fixation using chemical reductants, but little is known about their prospects for electrochemical reduction of dinitrogen. The viability of electrochemical N2 binding and splitting by a molybdenum(III) pincer complex, (pyPNP)MoBr3 (pyPNP = 2,6-bis(tBu2PCH2)-C5H3N)), is established in this work, providing a foundation for a detailed mechanistic study of electrode-driven formation of the nitride complex (pyPNP)Mo(N)Br. Electrochemical kinetic analysis, optical and vibrational spectroelectrochemical monitoring, and computational studies point to two reaction pathways: in the “reaction layer” pathway, the molybdenum(III) precursor is reduced by 2e– and generates a bimetallic molybdenum(I) Mo2(-N2) species capable of N–N bond scission. In the “bulk solution” pathway the precursor is reduced by 3e– at the electrode surface to generate molybdenum(0) species that undergo chemical redox reactions via comproportionation in the bulk solution away from the electrode surface to generate the same bimetallic molybdenum(I) species capable of N2 cleavage. The comproportionation reactions reveal the surprising intermediacy of dimolybdenum(0) complex trans,trans-[(pyPNP)Mo(N2)2](-N2) in N2 splitting pathways. The same “over-reduced” molybdenum(0) species was also found to cleave N2 upon addition of lutidinium, an acid frequently used in catalytic reduction of dinitrogen.

scholarly journals Controlling reaction pathways of selective C–O bond cleavage of glycerol

2018 ◽  
Vol 9 (1) ◽  
Author(s):  
Weiming Wan ◽  
Salai C. Ammal ◽  
Zhexi Lin ◽  
Kyung-Eun You ◽  
Andreas Heyden ◽  
...  
Keyword(s):  
Bond Cleavage ◽  
Reaction Pathways

Reaction pathways and roles of N-alkylmorpholine in amine·alane transamination: A mechanistic study

2014 ◽  
Vol 39 (10) ◽  
pp. 5003-5009 ◽  
Author(s):  
Chengbao Ni ◽  
Liu Yang
Keyword(s):  
Reaction Pathways ◽  
Mechanistic Study

Lead ion induced chemodosimeter approach of a tripodal hydroxyl-quinoline based phospho-ester through P–O bond cleavage

2016 ◽  
Vol 45 (22) ◽  
pp. 9187-9192 ◽  
Author(s):  
Dibyendu Sain ◽  
Chanda Kumari ◽  
Ashish Kumar ◽  
Hari Pada Nayek ◽  
Swapan Dey
Keyword(s):  
Bond Cleavage ◽  
Chelate Complex ◽  
Lead Ion

Pb2+ induced phosphoester hydrolysis followed by the formation of a penta coordinated chelate complex of lead.

scholarly journals Mechanistic Study of Diaryl Ether Bond Cleavage during Palladium‐Catalyzed Lignin Hydrogenolysis

ChemSusChem ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 4487-4494 ◽  
Author(s):  
Yanding Li ◽  
Steven D. Karlen ◽  
Benginur Demir ◽  
Hoon Kim ◽  
Jeremy Luterbacher ◽  
...  
Keyword(s):  
Bond Cleavage ◽  
Mechanistic Study ◽  
Ether Bond ◽  
Diaryl Ether ◽  
Palladium Catalyzed ◽  
Ether Bond Cleavage

Mechanistic study of a manganese porphyrin catalyst for on-demand production of chlorine dioxide in water

2015 ◽  
Vol 19 (01-03) ◽  
pp. 492-499 ◽  
Author(s):  
Scott D. Hicks ◽  
Silei Xiong ◽  
Curt J. Bougher ◽  
Grigori A. Medvedev ◽  
James Caruthers ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Chlorine Dioxide ◽  
Transfer Reaction ◽  
Water Soluble ◽  
Reaction Pathways ◽  
Mechanistic Study ◽  
Manganese Porphyrin ◽  
Oxygen Atom Transfer ◽  
On Demand ◽  
Proton Coupled Electron Transfer

A water-soluble manganese porphyrin complex was examined for the catalytic formation of chlorine dioxide from chlorite under ambient temperature at pH 5.00 and 6.90. Quantitative kinetic modeling allowed for the deduction of a mechanism that accounts for all experimental observations. Catalysis is initiated via an OAT (Oxygen Atom Transfer) reaction resulting in formation of a putative manganese(V) oxo species, which undergoes ET (Electron Transfer) with chlorite to form chlorine dioxide. As chlorine dioxide accumulates in solution, chlorite consumption slows down and ClO 2 reaches a maximum as the system reaches equilibrium. In phosphate buffer at pH 6.90, manganese(IV) oxo accumulates and its reaction with ClO 2 gives ClO 3-. However, at pH 5.00 acetate buffer proton coupled electron transfer (PCET) from chlorite to manganese(IV) oxo is fast and irreversible leading to chlorate formation only via the putative manganese(V) oxo species. These differences underscore how PCET rates affect reaction pathways and mechanism. The ClO 2 product can be collected from the aqueous reaction mixture via purging with an inert gas, allowing for the preparation of chlorine dioxide on-demand.

A mechanistic study of the C–P bond cleavage reaction of 1,2-(PH2)2-C6H4 with nBuLi/Sb(NMe2)3

2008 ◽  
pp. 6454 ◽  
Author(s):  
Ruth Edge ◽  
Robert J. Less ◽  
Vesal Naseri ◽  
Eric J. L. McInnes ◽  
Robert E. Mulvey ◽  
...  
Keyword(s):  
Bond Cleavage ◽  
Mechanistic Study ◽  
Cleavage Reaction ◽  
Bond Cleavage Reaction
Sign in / Sign up

Export Citation Format

Share Document