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Selective hydrogenation of α,β-unsaturated aldehydes over Au/MgxAlO hydrotalcite catalysts

Paper ID Volume ID Publish Year Pages File Format Full-Text
42455 45926 2009 7 PDF Available
Title
Selective hydrogenation of α,β-unsaturated aldehydes over Au/MgxAlO hydrotalcite catalysts
Abstract

Liquid-phase reduction of α,β-unsaturated aldehydes (UALs) to the corresponding α,β-unsaturated alcohols (UOLs) was investigated on gold catalysts supported on a solid base of MgxAlO hydrotalcite (x = Mg/Al molar ratio). The Au/MgxAlO catalysts were prepared using a modified deposition precipitation method without adjusting the pH of the initial HAuCl4 solution. The effects of various parameters involved in preparation of catalysts were also studied, including the Mg/Al molar ratio and the calcination temperatures of the MgxAlO support and Au/MgxAlO catalyst. The Mg/Al ratio of MgxAlO affected the pH of the final solution, and determined the actual gold loading in the catalyst. Calcination temperatures of the MgxAlO support and Au/MgxAlO catalyst determined the ratio of gold states (Au3+/Au0) on the catalyst. A correlation between the gold states (Au3+/Au0) and the activity and selectivity of UAL to UOL was found. Increasing the Au3+/Au0 ratio of the catalysts increased the activity and selectivity of UAL to UOL. The different performances of the Au/MgxAlO catalysts from Group VIII metals due to the effects of temperature, pressure and steric structures of UALs were discussed.

Graphical abstractGold dispersed on a solid base of MgxAlO hydrotalcite could selectively hydrogenate α,β-unsaturated aldehydes (UALs) to α,β-unsaturated alcohols (UOLs). A high selectivity of UOL was obtained at the complete conversion. A correlation between the gold states (Au3+/Au0) and the activity and selectivity was found. Increasing the Au3+/Au0 ratio of the catalyst increased the activity and selectivity of UAL to UOL.Figure optionsDownload full-size imageDownload as PowerPoint slide

Keywords
Gold catalysts; Hydrotalcite; MgxAlO; Selective hydrogenation; α,β-Unsaturated aldehyde
First Page Preview
Selective hydrogenation of α,β-unsaturated aldehydes over Au/MgxAlO hydrotalcite catalysts
Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volume 361, Issues 1–2, 20 June 2009, Pages 65–71
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis