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Published on: November 9, 2019
Recent advances in rice-derived heterogeneous catalysts for green organic synthesis
Radwan Ali1, Mohanad Y Saleh2, Ahmed M Amshawee3
1Department of Basic Sciences, College of Dentistry, Al-Qadisiyah University, Al-Qadisiyah, Iraq. radwan.ali@qu.edu.iq.
Abstract:
Organic synthesis plays a crucial role in achieving the principles of green chemistry by minimizing waste, utilizing cost-effective and abundant feedstocks, and enabling catalyst recyclability. In recent years, bio-based catalysis has emerged as a promising strategy due to its low environmental impact, reduced toxicity, and economic viability. Among various bio-derived materials, rice and its by-products have demonstrated significant potential as sustainable catalytic platforms. Owing to its rich composition of silica, carbon, and functionalizable organic matter, rice husk (RH) and rice straw ash (RSA) have been extensively explored for developing heterogeneous catalysts applicable in a wide range of organic transformations. This review highlights recent advances (2020-2025) in RH-based catalysis for green organic synthesis, covering diverse catalytic forms such as RH-activated carbon (RHAC), RH sulfonated carbon (SRH), RH silica (RHS), metal-doped silica, and RSA extracts. The discussed transformations include Knoevenagel condensation, Michael addition, Hantzsch synthesis, multicomponent cyclizations, Suzuki-Miyaura and Heck cross-couplings, Friedel-Crafts alkylation, benzylation, tert-butylation of aromatics. Emphasis is placed on the synthesis, functionalization, and catalytic mechanisms of rice-derived materials, as well as their reusability, efficiency under mild conditions, and alignment with green chemistry goals. This review aims to provide a comprehensive overview of the evolving landscape of rice-based biocatalysts in modern organic synthesis.
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