Kinetic Studies of Acetate Exchange intrans-4-Acetoxy-[η3-(1,2,3)-cyclohexenyl]palladium Complexes. Relevance for Asymmetric 1,4-Oxidation Reactions

2002 ◽  
Vol 21 (16) ◽  
pp. 3367-3375 ◽  
Author(s):  
Hanna K. Cotton ◽  
Renzo C. Verboom ◽  
Lars Johansson ◽  
Bernd J. Plietker ◽  
Jan-E. Bäckvall
Keyword(s):  
Kinetic Studies ◽  
Palladium Complexes ◽  
Oxidation Reactions

Synthesis and Characterization of Novel PEPPSI type Pd–BICAAC Complexes

2022 ◽  
Author(s):  
Márton Nagyházi ◽  
Balázs Almási ◽  
Ádám Lukács ◽  
Attila Bényei ◽  
Tibor Nagy ◽  
...  
Keyword(s):  
High Activity ◽  
Coupling Reaction ◽  
Kinetic Studies ◽  
Elemental Mercury ◽  
Palladium Complexes ◽  
Synthesis And Characterization ◽  
Heck Coupling ◽  
Moisture Resistant

A series of bicyclic alkylamino carbenes (BICAAC) (where N-aryl = dipp, mes, 2,6-dimethyl-4-(dimethylamino)phenyl, 5a-d) and their novel air- and moisture-resistant pyridine (pyridine, 4 dimethylaminopyridine) containing palladium PEPPSI-type Pd(II) complexes (6a-e) were synthetized and characterized. The new palladium complexes have shown high activity in Mizoroki–Heck coupling reaction even at as low as 100 ppm loading (TON up to 10000). Kinetic studies revealed that reactions carried out in the presence of elemental mercury resulted in decrease in activity. It indicates that the coupling reaction may have both molecular and Pd(0)-mediated catalytic paths.

scholarly journals New Insights into the Electrocatalytic Mechanism of Methanol Oxidation on Amorphous Ni-B-Co Nanoparticles in Alkaline Media

Catalysts ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 749 ◽  
Author(s):  
Wu ◽  
Zhang ◽  
Zhang ◽  
Duan ◽  
Li ◽  
...  
Keyword(s):  
Methanol Oxidation ◽  
Amorphous Materials ◽  
Reaction Order ◽  
Chemical Reduction ◽  
Three Dimensional ◽  
Kinetic Studies ◽  
Alkaline Media ◽  
Methanol Oxidation Reaction ◽  
Oxidation Reactions ◽  
Co Nanoparticles

Despite an increased interest in sustainable energy conversion systems, there have been limited studies investigating the electrocatalytic reaction mechanism of methanol oxidation on Ni-based amorphous materials in alkaline media. A thorough understanding of such mechanisms would aid in the development of amorphous catalytic materials for methanol oxidation reactions. In the present work, amorphous Ni-B and Ni-B-Co nanoparticles were prepared by a simple chemical reduction, and their electrocatalytic properties were investigated by cyclic voltammetry measurements. The diffusion coefficients (D0) for Ni-B, Ni-B-Co0.02, Ni-B-Co0.05, and Ni-B-Co0.1 nanoparticles were calculated to be 1.28 × 10−9, 2.35 × 10−9, 4.48 × 10−9 and 2.67 × 10−9 cm2 s−1, respectively. The reaction order of methanol in the studied transformation was approximately 0.5 for all studied catalysts, whereas the reaction order of the hydroxide ion was nearly 1. The activation energy (Ea) values of the reaction were also calculated for the Ni-B and Ni-B-Co nanoparticle systems. Based on our kinetic studies, a mechanism for the methanol oxidation reaction was proposed which involved formation of an electrocatalytic layer on the surface of amorphous Ni–B and Ni-B-Co nanoparticles. And methanol and hydroxide ions could diffuse freely through this three-dimensional porous conductive layer.

Kinetic Studies in the Chemistry of Rubber and Related Materials. III. Thermochemistry and Mechanisms of Olefin Oxidation

1947 ◽  
Vol 20 (3) ◽  
pp. 617-626
Author(s):  
J. L. Bolland ◽  
Geoffrey Gee
Keyword(s):  
Kinetic Studies ◽  
Ethyl Linoleate ◽  
Oxidation Products ◽  
Oxidation Reactions ◽  
Olefin Oxidation ◽  
Primary Products ◽  
Resonance Energies ◽  
Oxidation Chain ◽  
Bond Strengths

Abstract A new estimate of the O—O bond strength in hydroperoxides is reported, based on a determination of the heats of oxidation of ethyl linoleate and linolenate. This value is employed, together with other known bond strengths and resonance energies, to estimate the heats of a number of alternative oxidation reactions of olefins. By considering the effects of the olefin structure on these heats of reaction, it is possible to see how structural differences can lead to the formation of different oxidation products. The discussion is confined to primary products of the oxidation chain, but, even so, a considerable diversity of behavior is shown to be possible. The final material may include simple monomeric hydroperoxides, polymers with varying amounts of oxygen incorporated in the chain, cyclic peroxides, and scission products. The very limited experimental evidence available falls generally into line with expectation.

Synthesis of amino-phenolate manganese complexes and their catalytic activity in carbon dioxide activation and oxidation reactions

2020 ◽  
pp. 1-7
Author(s):  
Ali I. Elkurtehi ◽  
Francesca M. Kerton
Keyword(s):  
Carbon Dioxide ◽  
Variable Temperature ◽  
Styrene Oxide ◽  
Aerobic Oxidation ◽  
Kinetic Studies ◽  
Cyclic Carbonate ◽  
Oxidation Reactions ◽  
Co Catalyst ◽  
Carbonate Formation ◽  
Solvent Free Conditions

Two manganese(III) compounds were studied as catalysts for the reaction of carbon dioxide with propylene oxide, styrene oxide, and cyclohexene oxide, and formed cyclic carbonate products selectively under solvent free conditions in the presence of an ionic co-catalyst such as TBAB or PPNCl. Variable temperature kinetic studies allowed the activation energy for propylene carbonate formation to be determined (64 kJ mol−1). The catalysts showed good stability in these reactions and overall turnover numbers (TON) of up to 6000 were observed. The complexes showed low activity for the aerobic oxidation of 4-methyoxybenzylalcohol to the corresponding aldehyde, achieving up to 40% conversion in 72 h. However, near quantitative conversion of 1,2-diphenyl-2-methoxyethanol to provide up to 90% yield of benzaldehyde could be achieved over the course of 5 days. Both complexes showed similar reactivity in the two catalytic processes, and this is likely due to the weakly coordinating nature of the pendant donor within the tetradentate ligand.

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