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Study of the citral/acetone reaction on MgyAlOx oxides: Effect of the chemical composition on catalyst activity, selectivity and stability

Paper ID Volume ID Publish Year Pages File Format Full-Text
43692 45983 2008 9 PDF Available
Title
Study of the citral/acetone reaction on MgyAlOx oxides: Effect of the chemical composition on catalyst activity, selectivity and stability
Abstract

The liquid-phase citral/acetone reaction was studied on MgO, Al2O3 and MgyAlOx mixed oxides with Mg/Al molar ratios of 0.11–3. The density, strength and nature of surface acid sites were determined by NH3 thermodesorption and FTIR of pyridine. The surface basic properties were probed by temperature-programmed desorption of CO2. The rate of the citral/acetone cross-aldolization to pseudoionones increased linearly with the density of strong O2− base sites. Thus, the pseudoionone synthesis was efficiently promoted on MgO and Mg-rich MgyAlOx samples. In contrast, the initial rate of the parallel acetone self-condensation reaction increased with the density of Lewis acid sites, and diacetone alcohol was more rapidly formed on Al2O3 and Al-rich MgyAlOx samples. Differences in the reactant adsorption strength on surface Al3+ sites may explain the observed differences between the acid-catalyzed mechanisms of cross- and self-aldolization reactions. In situ catalyst deactivation was determined by performing two consecutive catalytic runs. The activity decay of MgyAlOx samples during the citral/acetone reaction was between 15 and 20%, irrespective of the catalyst composition.

Graphical abstractThe liquid-phase citral/acetone reaction was studied on MgO, Al2O3 and MgyAlOx mixed oxides. The rate of the citral/acetone cross-aldolization to pseudoionones increased linearly with the density of strong O2− base sites. In contrast, the initial rate of the parallel acetone self-condensation reaction augmented with the density of Lewis acid sites.Figure optionsDownload full-size imageDownload as PowerPoint slide

Keywords
Citral/acetone reaction; MgyAlOx catalysts; Aldol condensation; Pseudoionone synthesis; Fine chemicals
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Study of the citral/acetone reaction on MgyAlOx oxides: Effect of the chemical composition on catalyst activity, selectivity and stability
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volume 345, Issue 2, 1 August 2008, Pages 143–151
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
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Full-text PDF Download
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