نتایج جستجو برای: selective oxidation

تعداد نتایج: 311890  

2008
M. Martinez B. Viguier P. Maugis J. Lacaze

The relation between chemical composition, microstructure and oxidation properties has been investigated on various FeAl based alloys, the aim being to induce changes in the microstructure of the compound by selective oxidation of aluminium. Oxidation kinetics that was evaluated on bulk specimens showed that, due to fast diffusion in the alloys, no composition gradient is formed during the alum...

Journal: :Plant physiology 1984
P Ravanel M Tissut R Douce

The effects of several rotenoids have been studied on potato (Solanum tuberosum L.) tuber and etiolated mung bean (Phaseolus aureus Roxb.) hypocotyls mitochondria. The selective inhibition of mitochondrial complex I is characterized by several tests: (a) no effect can be observed on exogenous NADH or succinate oxidation; (b) malate oxidation is inhibited at pH 7.5; (c) one-third decrease of ADP...

2009
Graham J. Hutchings

Heterogeneous catalysis plays a key role in the manufacture of essential products in key areas of agriculture and pharmaceuticals, but also in the production of polymers and numerous essential materials. Our understanding of heterogeneous catalysts is advancing rapidly, especially by using the latest characterisation methods on these relatively complex effect materials. At the heart of these ca...

2003
Georgios Kyriakou Federico J Williams Mintcho S Tikhov Richard M Lambert

Alkene selective oxidation is of major technological importance since alkene epoxides are versatile chemical intermediates used in the manufacture of a wide range of commodity and fine chemicals. The reaction itself is mechanistically very interesting and it has attracted a lot of the academic interest over many years. Various models have been proposed in order to explain why the reaction is ap...

2013
Pu Ma Huamin Zhai

Carboxylic acid groups were introduced onto thermomechanical pulp (TMP) long fiber surfaces by 2,2,6,6,tetramethylpiperidine-1-oxyl radical (TEMPO)-mediated oxidation in the present study. The number of introduced carboxylic groups was closely related to the NaClO dosage, and more flexible fibers with lower curl and kink index were generated. Lignin was dissolved during the TEMPO-mediated oxida...

Journal: :Chemical communications 2010
Joanna Dzierzak Emanuela Bottinelli Gloria Berlier Enrica Gianotti Eugen Stulz Radoslaw Michal Kowalczyk Robert Raja

Transition-metal complexes containing amino acids encapsulated within solid supports generate isolated active centres that function as effective selective oxidation catalysts using benign oxidants such as air and display high turnovers and selectivity in industrially significant oxidation reactions.

2013
Lennart Möhlmann Stefan Ludwig Siegfried Blechert

This publication describes a highly selective oxidation of aldehydes to the corresponding acids or esters. The reaction proceeds under metal-free conditions by using N-heterocyclic carbenes as organocatalysts in combination with environmentally friendly oxygen as the terminal oxidation agent.

2017
John J. Molloy Thomas A. Clohessy Craig Irving Niall A. Anderson Guy C. Lloyd-Jones Allan J. B. Watson

We report the direct chemoselective Brown-type oxidation of aryl organoboron systems containing two oxidizable boron groups. Basic biphasic reaction conditions enable selective formation and phase transfer of a boronic acid trihydroxyboronate in the presence of boronic acid pinacol (BPin) esters, while avoiding speciation equilibria. Spectroscopic investigations validate a base-promoted phase-s...

2016
Catherine Brookes Michael Bowker Peter P. Wells

In industry, one of the main catalysts typically employed for the selective oxidation of methanol to formaldehyde is a multi-component oxide containing both bulk Fe2(MoO4)3 and excess MoO3. It is thought that the excess MoO3 primarily acts to replace any molybdenum lost through sublimation at elevated temperatures, therefore preventing the formation of an unselective Fe2O3 phase. With both oxid...

2016
Thomas Sheppard Helen Daly Alex Goguet Jillian M Thompson

The mono(μ-oxo) dicopper cores present in the pores of Cu-ZSM-5 are active for the partial oxidation of methane to methanol. However, copper on the external surface reduces the ratio of active, selective sites to unselective sites. More efficient catalysts are obtained by controlling the copper deposition during synthesis. Herein, the external exchange sites of ZSM-5 samples were passivated by ...

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