fulltext.study @t Gmail

The oxidation of 2-methyl-1-naphthol to menadione with H2O2, catalyzed by Nb-based heterogeneous systems

Paper ID Volume ID Publish Year Pages File Format Full-Text
42544 45930 2009 5 PDF Available
Title
The oxidation of 2-methyl-1-naphthol to menadione with H2O2, catalyzed by Nb-based heterogeneous systems
Abstract

This paper examines the reactivity of catalysts based on niobium oxide dispersed in silica, for the oxidation of 2-methyl-1-naphthol to 2-methyl-1,4-naphthoquinone (menadione) with aqueous hydrogen peroxide. The catalytic performance is affected by the hydroperoxide concentration, and by the mode of oxidant addition. The reaction scheme is rather complex, including, along with the desired reaction, also parallel and consecutive side processes. The catalyzed oxidation reaction to yield menadione is always accompanied by radical reactions leading to coupling products. The use of diluted hydrogen peroxide solutions (concentration 3.5 wt.%) favors the formation of these heavy compounds. On the other hand, in the presence of concentrated hydrogen peroxide solution (35 wt.%), the oxidation of the substrate to menadione occurs even without catalyst. High selectivity to menadione (i.e., 93%) is achieved only at the very beginning of the reaction when the substrate is added to the catalyst-containing hydrogen peroxide solution, the oxidant concentration being 35%. Under the latter conditions, the low concentration of substrate disfavors the undesired coupling reactions.

Graphical abstractThis paper examines the reactivity of catalysts based on niobium oxide dispersed in silica, for the oxidation of 2-methyl-1-naphthol to 2-methyl-naphthoquinone (menadione) with aqueous hydrogen peroxide. The catalytic performance is affected by the hydroperoxide concentration, and by the mode of oxidant addition. The reaction scheme is rather complex, including, along with the desired reaction, also parallel and consecutive side processes.Figure optionsDownload full-size imageDownload as PowerPoint slide

Keywords
2-Methyl-1-naphthol; 2-Methylnaphthoquinone; Menadione; Niobia-silica; Selective oxidation; Hydrogen peroxide
First Page Preview
The oxidation of 2-methyl-1-naphthol to menadione with H2O2, catalyzed by Nb-based heterogeneous systems
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us
Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volume 356, Issue 2, 15 March 2009, Pages 162–166
Authors
, , , , , , ,
Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us