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Ni/SiO2 catalysts prepared with ethylenediamine nickel precursors: Influence of the pretreatment on the catalytic properties in glucose hydrogenation

Paper ID Volume ID Publish Year Pages File Format Full-Text
44066 46002 2007 9 PDF Available
Title
Ni/SiO2 catalysts prepared with ethylenediamine nickel precursors: Influence of the pretreatment on the catalytic properties in glucose hydrogenation
Abstract

Nickel catalysts prepared with different metal loadings (5, 10, and 20 wt% Ni) by impregnation with nickel ethylenediamine complexes revealed small nickel particles (mean diameter: 2–3 nm) after reduction, even for high metal loadings (20 wt%). When used in the hydrogenation of glucose, these catalysts show almost no nickel leaching compared to a commercial Ni/SiO2 catalyst (prepared by precipitation, 67 wt% Ni), but they are slightly less active (TOF: 2 to 10 × 10−3 s−1) than a commercial nickel/silica catalyst (TOF: 14 × 10−3 s−1) and revealed lower yields to sorbitol (3–42% compared to 60%). The catalytic results depend on the pretreatment conditions performed. When the catalysts are calcined before reduction, higher conversion (19–45%) and selectivity to sorbitol (81–92%) are obtained than when they are directly reduced without calcination pretreatment (conversion: 10–16% and selectivity to sorbitol: 21–59%) after 5 h of reaction time, respectively. The difference was ascribed to the fact that complete decomposition of the nickel ethylenediamine precursor was achieved only when calcination pretreatment was performed. Indeed, when the catalysts were directly reduced, X-ray photoelectron spectroscopy (XPS) revealed a nitrogen-compound probably responsible for lower conversion and higher selectivities to fructose and mannose, indicating Lobry de Bruyn-Alberda van Ekenstein rearrangement. However, no nickel sintering was observed in contrast to the catalyst calcined before reduction.

Graphical abstractTo overcome nickel leaching, Ni/SiO2 catalysts (5, 10, and 20 wt%) were prepared using nickel ethylenediamine complexes. In glucose hydrogenation, they show almost no leaching, but slightly lower activity (TOF) and lower yields to sorbitol compared to an industrial catalyst. The catalytic results depend on the pretreatment performed.Figure optionsDownload full-size imageDownload as PowerPoint slide

Keywords
Hydrogenation; Glucose; Sorbitol; Nickel catalysts; Leaching
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Ni/SiO2 catalysts prepared with ethylenediamine nickel precursors: Influence of the pretreatment on the catalytic properties in glucose hydrogenation
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volume 318, 20 February 2007, Pages 45–53
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
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Price was $35.95
You save - $31
Price after discount Only $4.95
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