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CoBr2-MnBr2 containing catalysts for catalytic oxidation of p-xylene to terephthalic acid

Paper ID Volume ID Publish Year Pages File Format Full-Text
43477 45971 2008 7 PDF Available
Title
CoBr2-MnBr2 containing catalysts for catalytic oxidation of p-xylene to terephthalic acid
Abstract

Catalytic oxidation of p-xylene (PX) to terephthalic acid (TA) was studied with catalysts containing cobalt acetate, manganese acetate, CoBr2 and MnBr2. The catalysts contain neither highly corrosive hydrogen bromide nor other metal ions, and have the advantage of easy catalyst recovery. The effects of Br/Co atomic ratio, reaction time and temperature, PX concentration, oxygen pressure, and catalyst concentration on PX conversion and product/intermediate yields were investigated. The catalyst system had a suitable reaction temperature of 100 °C, which was much lower than the commercial process temperature (175–225 °C). The maximum product (TA) yield was 93.5%, obtained at a Br/Co atomic ratio of three. Higher Br concentration resulted in the lower TA yield, which was ascribed to the benzylic bromide formation. The synthesis of TA could be adequately described as four reaction steps in series (PX → p-tolualdehyde → p-toluic acid → 4-carboxybenzaldehyde → TA), with a pseudo-first-order rate equation for each step, and the third step was rate-limiting. The rate constant ratios (kj/k3, j = 1 → 4) obtained at 100 °C were similar to the kj/k3 values reported earlier for cobalt acetate/manganese acetate/HBr catalysts in a range of 185–191 °C.

Graphical abstractCatalytic oxidation of p-xylene to terephthalic acid was studied with catalysts containing CoBr2 and MnBr2. The catalysts contain neither highly corrosive hydrogen bromide nor other metal ions, and have the advantage of easy catalyst recovery. The maximum product yield obtained was 93.5% at 100 °C, which was much lower than the reaction temperature used for the commercial processes (175–225 °C).Figure optionsDownload full-size imageDownload as PowerPoint slide

Keywords
Oxidation catalysts; Cobalt bromide; Manganese bromide; p-Xylene; Terephthalic acid
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CoBr2-MnBr2 containing catalysts for catalytic oxidation of p-xylene to terephthalic acid
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volume 340, Issue 2, 1 June 2008, Pages 271–277
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
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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
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