Tuning the acidic–basic properties by Zn-substitution in Mg–Al hydrotalcites as optimal catalysts for the aldol condensation reaction

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• 作者：Willinton Y. Hernández ; Funda Aliç ; An Verberckmoes…
• 刊名：Journal of Materials Science
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：52
• 期：1
• 页码：628-642
• 全文大小：1,254 KB
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Chemistry<br>Materials Science<br>Characterization and Evaluation Materials<br>Polymer Sciences<br>Continuum Mechanics and Mechanics of Materials<br>Crystallography<br>Mechanics<br>
• 出版者：Springer Netherlands
• ISSN：1573-4803
• 卷排序：52

文摘

Mg–Zn–Al hydrotalcites and derived mixed oxides with different Mg2+-to-Zn2+ ratios were prepared by co-precipitation in super-saturated conditions, followed by thermal decomposition at 500 °C. The synthesized materials were evaluated as catalysts for the self-condensation of octanal in order to establish structure-to-functionality properties of the prepared materials. The presence of zinc affects the structural and textural properties of the as-synthesized hydrotalcites and derived mixed oxides, and provokes a remarkable modification on the acidic–basic properties of the materials as studied by COb>2b> and NHb>3b>-TPD. The presence of Zn2+ caused an increment in the concentration of surface acidic sites compared to the binary Mg–Al system. The samples characterized by a Zn/Mg ratio ≤1 showed the optimal ratio of acidic and basic sites and the best catalytic performance for the production of the α,β-unsaturated aldehyde. The reconstruction of the layered materials (starting from the mixed oxides) caused an increment in the concentration of surface OH− groups, further modifying the selectivity of the reaction.