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<p>In this study, the Knoevenagel condensation reaction between vanillin and malononitrile was studied using a heterogeneous catalyst such as MCM-41 with a to nominal nickel loadings of 10.2 wt%, under microwave heating. Vanillin, a lignin-derived compound, was used as a model substrate due to its renewable origin and potential for the synthesis of high value-added products. The effects of temperature, amount of catalyst, nickel content and heating method on product yield and selectivity were evaluated. The results show that the best reaction conditions were achieved at 100&#xa0;°C with 40&#xa0;mg of catalyst, reaching a conversion and selectivity close to 99% in only 90&#xa0;min using microwaves. Additionally, it was observed that increasing the nickel loading enhanced the catalytic activity, promoting the deprotonation of malononitrile and favoring the formation of the desired product. The Ni/MCM-41(10) catalyst showed high stability and reusability, maintaining its activity after five reaction cycles with a slight decrease in yield. Furthermore, the methodology was successfully extended to other biomass-derived aldehydes, such as furfural and piperonal, confirming the versatility of the catalytic system and its suitability for sustainable syntheses. This work highlights the combination of heterogeneous catalysts and microwave heating as an efficient and environmentally friendly strategy in green chemistry.</p>

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Enhancing efficiency in Knoevenagel condensation: a sustainable approach using mesoporous catalysts and microwaves

  • 期刊论文

  • 发表日期：

    2025年12月5日

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  • Eliana Nope,
  • Paola M. Carraro,
  • Ángel G. Sathicq,
  • Griselda A. Eimer,
  • Marcelo Murguía,
  • Gustavo P. Romanelli

摘要

In this study, the Knoevenagel condensation reaction between vanillin and malononitrile was studied using a heterogeneous catalyst such as MCM-41 with a to nominal nickel loadings of 10.2 wt%, under microwave heating. Vanillin, a lignin-derived compound, was used as a model substrate due to its renewable origin and potential for the synthesis of high value-added products. The effects of temperature, amount of catalyst, nickel content and heating method on product yield and selectivity were evaluated. The results show that the best reaction conditions were achieved at 100 °C with 40 mg of catalyst, reaching a conversion and selectivity close to 99% in only 90 min using microwaves. Additionally, it was observed that increasing the nickel loading enhanced the catalytic activity, promoting the deprotonation of malononitrile and favoring the formation of the desired product. The Ni/MCM-41(10) catalyst showed high stability and reusability, maintaining its activity after five reaction cycles with a slight decrease in yield. Furthermore, the methodology was successfully extended to other biomass-derived aldehydes, such as furfural and piperonal, confirming the versatility of the catalytic system and its suitability for sustainable syntheses. This work highlights the combination of heterogeneous catalysts and microwave heating as an efficient and environmentally friendly strategy in green chemistry.