Design and Synthesis of Heterogeneous Nanocatalysts Based on Immobilized Metals on Polymeric Substrates and their Applications in Organic Reactions

Motamedi, Anahita | 2018

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 51290 (03)
  4. University: Sharif University of Technology
  5. Department: Chemistry
  6. Advisor(s): Pourjavadi, Ali
  7. Abstract:
  8. Today, catalysts have shown the growing applications in chemical industries especially for drug synthesis. Using immobilized heterogeneous catalysts is a sensible way to benefit from advantages of both heterogeneous and homogeneous catalysts. In this regards, homogeneous catalysts are immobilized on to a solid support through various methods. However, low loading amount of homogenous part and subsequently insufficient catalytic activity are main limitations of immobilized heterogeneous catalysts. For this reason, polymeric supports have been introduced to immobilize metal ions or nanoparticles. These polymeric supports not only possess advantages such as anti-corrosive properties, simple separation, and easy preparation, but also they are able to adsorb and maintain metal ions properly. In the present work, stable complexes between metal ions and polymer have shown high loading of metals and excellent catalytic activity of the prepared catalysts. Furthermore, cross-linked and porous polymeric supports were used to promote accessibility of inner sites of polymer chains to the starting materials and subsequently increase the catalytic activity. A promising innovation in this project has been using of double network hydrogels, with great mechanical strengths and high porosity, as the support for immobilized heterogeneous catalyst. The loading capacity of these new type of hydrogels is high for various nanoparticles, which decreases the amount of catalyst required for chemical reactions and improves the performance and activity of them in the reactions. The main goal of the thesis is preparation of catalysts with high loading of metal ions and high catalytic activity along with an easy separation. Hence, the solid support was synthesized via covering of magnetic nanoparticles with insoluble cross-linked polymers; subsequently, metal ions and nanoparticles including Cu and Pd as well as Au were immobilized on to the support. The catalytic activity of the prepared heterogeneous catalysts was evaluated in various reactions including oxidation of alcohols, reduction of nitro-aromatic compounds, coupling reactions, and synthesis of triazoles
  9. Keywords:
  10. Catalytic Activity ; Double Network Hydrogel ; Catalyst Properties ; Nanomagnetic Catalyst ; Heterogeneous Nanocatalyst ; Hydrogel Nanocomposite

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