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چکیده
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Use of agricultural wastes such as: rice husk, wheat bran, coconut husk, especially those containing silica, can be considered in the production of high value-added products as a potential adsorbent and cause extraordinary improvements in the synthesis of organic compounds [1]. The advantages of this type of waste include: environmentally friendly, renewable source, high availability and low cost, and can be considered as an option for the synthesis of catalysts [2]. First, nanosilica extracted from rice husk was prepared and then equipped with magnetic properties by fixing iron and nickel bimetallic nanoparticles on the silica surface. The synthesized compound was used as a recyclable magnetic catalyst in the three-component condensation reactions of 1-H-benzo [f] chromene. Easy separation of catalyst and products, efficiency and proper reaction time, mild conditions and reuse are some of the advantages of catalyst used. 1-H- Benzo [f] chromene and their derivatives are of particular importance due to their wide range of biological properties including antihypertensive, antispasmodic and anticancer activity [3]. In this work, 1-H-benzo [f] chromene derivatives 4 via a three-component condensation of aromatic aldehydes, malononitrile and b-naphthol were synthesized in the presence of Fe- Ni/RH-SiO2 catalyst under optimal conditions with excellent efficiency. The resulting nanocomposite was studied by EDX, FESEM, TGA, FT-IR, VSM and XRD techniques. Scheme 1. Synthesis of three-component reaction in the presence of catalyst
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