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Pedro J. Pérez Universidad de Huelva Toward Sustainable Chemistry: METhodologies for HEterogenising HOmogenous CATalysts (METHEHOCAT)
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Sustainable chemistry Safer reactions Catalysis Renewable materials Waste decrease Energy efficiency Minimize solvents Atomic Selectivity Non-toxic reagents Sustainable chemistry
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C C-RC-P R P Catalysis Chemical process: Reactants (R) Products (P) But… -Many reactions are slow -Many reactions give more than one product A catalyst (C) is a compound that increases the reaction rate (faster processes) and provides the product we look for, avoiding other non-desired products (selectivity). It works one time after another in the so-called catalytic cycle.
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Homogeneous and heterogeneous catalysis The catalysis is homogeneous if the catalyst is dissolved in the same phase than reactants. The catalysis is heterogeneous if the catalyst is not dissolved in the same phase than reactants, and usually can be easily separated at the end of the process, allowing its recycling.
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Goal #1: heterogenize the homogenous We have already described homogenous catalysts for several transformations. The main goal of this joint project is to develop heterogeneous catalysts based in the anchoring technique, in which the homogeneous catalysts will be fixed onto the solid surface. Such fixation will be performed in such a way that the metal centre will behave identically to the homogeneous counterpart. zeolite SBA-15 (silica) MCF (silica)
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Strategy and workplan 1) Preparation of catalyst precursors at UHU 2) Fixation onto solid supports at UALG 3) Catalytic tests and catalyst recycling studies at UHU 4) Data analysis and re-design for optimization (UHU-UALG)
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Goal #2: improving selectivity The catalyst developed at UHU are based in pyrazolyl rings: In order to improve the selectivity (enantioselectivity) in several transformations, it would be useful to prepare new molecules containing pyrazoles containing stereocenters (a chiral atom). This constitutes the second goal of this project, that will serve to develop mor selective catalysts for certain transformations.
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Strategy and workplan 1) Preparation of chiral pyrazoles at UALG 2) Preparation of catalyst precursors at UHU 3) Catalytic tests at UHU 4) Data analysis and re-design for optimization (UHU-UALG)
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Preliminary results Goal #1: Catalyst precursors already prepared at UHU. If X=SH it may be supported onto a Au film SOLID SUPPORT AuFILMAuFILM
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Preliminary results
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Strategy Another approach, much interesting and innovative will be the design and preparation with the stereocentre on the metal (“active site”)
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Strategy
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Preliminary results Possible types of spacer
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Pyrazol position of connection with the spacer: strain for coordination
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ERA Chemistry Homogeneous Catalysis Laboratory
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