Nanocatalysis for Green Synthesis Seminar Research for B.Sc Students

Green Chemistry: Technologies that are energy efficient, minimize or preferably eliminate the formation of waste, avoid the use of toxic and/or hazardous solvents and reagents and, where possible, utilize renewable raw materials

New synthetic methods is required!! R. A. Sheldon in “Green Chemistry and Catalysis” 2007, P. 3

Replacing traditional synthetic methods by green methods

Our Research 1.Heterogenization of homogeneous catalysts 2.Ionic liquid-based catalytic nanoreactors 3.Magnetically separable organocatalysts 4.Multicomponent reactions (MCRs)

Catalysis (Green Synthetic Process) HomogeneousHeterogenous Organometallic complexes Supported metals Supported organometallic complexes Metal oxides, sulfides Two phasesOne phase

Homogeneous catalysisHeterogeneous catalysis K. D. Wiese et al, Top Organomet. Chem., 2006, 18, 1. H. W. Bohnen et al, Adv. Catal. 2002, 47, 1. High activity and selectivity Not easily recovered Expensive Decrease of activity and selectivity Easily recovered Economic How to combine between homogeneous and heterogeneous catalysis?!! Catalysis

Example 1: Hydroformylation of Alkenes

Hydroformylation in Industry Largest homogeneous catalytic process Commercial aldehydes: 9.2x10 6 tons/year Catalysts: complexes of rhodium and cobalt The Ruhrchemie/ Rhone Poulenc hydroformylation Process Water soluble ligand L= H-Rh(CO)L 3 Catalyst B. Cornils, E. Wiebus, Chemtech, 1995, 25, 33

New strategy: homogeneous-heterogeneous hydroformylation catalysts Ideal hydroformylation catalyst: selectivity, activity, recovering Minimizing the support for the immobilization Enhancement of the support “solubility” in organic solvents by dendrimerizing process Tethering metallic complexes to the periphery of the dendrimerized supports for enhancement of their compatibility with the media and surrounding Magnetization of the minimized supports

Synthesis of silica-coated nano-magnetite * mmol/g of amino groups R. Abu-Reziq et al. J. Am. Chem. Soc., 2006, 128, 5279.

TEM micrographs of nano-magnetite before and after coating with silica before coating 8-12 nm after coating nm scale bar: 50 nmscale bar: 10 nm

Dendrimerizing process of the silica-coated nano-magnetite

*After the dendrimerizing process, the silica-coated magnetic nanoparticles are more stable and more soluble in organic solvents.

IR Spectra and TGA-curves of silica-coated magnetic nanoparticles supported dendrimers

Rhodium complexed dendrimers supported on silica-coated magnetite nanoparticles

Industrial applications in hydroformylation of vinylarenes Nonsteroidal antiinflammatory agents

Applications of the dendrimerized catalyst in hydroformylation reaction G(1)-Rh is the most selective and active catalyst Temperature: RT to 50 °C High selectivity and reactivity is in applying non-polar solvents dichloromethane> toluene> benzene Polar solvents (THF, CH 3 CN, ether) reduce the reactivity and selectivity B:L > 45:1 R. Abu-Reziq et al. J. Am. Chem. Soc., 2006, 128, 5279.

Hydroformylation of various vinylarenes by the dendrimerized catalyst

Hydroformylation of various vinylarenes by the dendrimerized catalyst

Recycling of the dendrimerized catalyst in hydroformylation of styrene

Example 2: Hydrogenation of α,β-unsaturated aldehydes Catalysts: supported Pt 0 or Ru 0 modified by Lewis acids (Sn n+, Fe 3+ ) Application in fragrance and flavor industry Catalyst for industrial applications: effective, selective, recyclable

Design of new catalyst for selective hydrogenation Platinum nanoparticlesMagnetic nanoparticles Selectivity Ease of separation and recovering Homogeneous system (nano-support) Electronic factor (efficacy)

Platinum loading of 10 % Synthesis of platinum nanoparticles supported on ionic liquid-modified magnetic nanoparticles R. Abu-Reziq et al. Adv. Synth. Catal, 2007, 349, 2145.

TEM micrographs of platinum nanoparticles supported on ionic liquid-modified magnetic nanoparticles scale bar 20 nmscale bar 10 nm

Applications in hydrogenation of α,β-unsaturated aldehydes 100 % of selectivity toward allyl alcohols

Applications in hydrogenation alkynes runSubstrateConversion (%)Products (Yield %) 1diphenylacetylene 100 cis-stilbene (95), trans-stilbene (5) 2diphenylacetylene97cis-stilbene (92), trans-stilbene (5) 3diphenylacetylene99cis-stilbene (93), trans-stilbene (6) 4diphenylacetylene97cis-stilbene (93), trans-stilbene (4) Recycling of MNP-IL-C8-Pt in the hydrogenation of diphenylacetylene

OEt OEt EtO- Si - OEt + H 2 O EtO-Si- OH OEt OEt Oil phase: TEOS +IL/Catalyst Water OEt EtO- Si- OEt OEt 1/ Hydrolysis + OEt OEt OEt EtO- Si- O- Si- O- Si-OEt OEt OEt OEt n 2/ Peripheral Polycondensation EtOH Nano-emulsification New Method: Catalytic Nanoreactors Catalyst + Magnetic nanoparticles

How it works??? Catalysts:

Ionic Liquids: Ionic liquids are compounds composed entirely of ions, with melting points below room temperature. P. Wasserscheid, T. Welton in “ Ionic Liquids in Synthesis” 2002.

Ionic Liquids- Synthesis

Advantages of Ionic Liquids: Zero vapour Pressure, non-flammable High solvation capacities No hydrolysis Environmentally benign and recyclable “designer solvents”

Ionic Liquids- Applications: Organic synthesis Chiral synthesis Polymerization Catalysis Extraction Separation

Task Specific Ionic Liquids

Chiral Task-Specific Ionic Liquids For example

36 Multicomponent reactions (MCRs) are general defined as reactions where more than two starting materials to react to form a product, incorporating essentially all of the atoms of the educts. Multicomponent Reactions Unlike the usual stepwise formation of individual bonds in the target molecule, the utmost attribute of MCRs is the inherent formation of several bonds in one operation, ideally without isolating the intermediates, changing the reaction conditions, or adding further reagents.

37 Mannich Reactions Multicomponent Reactions

38 Multicomponent Reactions Passerini Three Component Reaction (P-3CR)

39 Ugi Four Component Reaction (U-4CR) Multicomponent Reactions

Seeking for New MCRs

Subsequent MCR/ Diels-Alder or Click Reactions

Synthesis of Natural Product-Like Macrocycles

Double capsules: microcapsules Catalysts: Acid/ Base Organometallic complexes/ Organocatalysts Oxidants/ Reducing agents

Synergism between metal nanoparticles and dissolved organometallic complexes inside nanocapsules Catalysis target: Hydrogenations and carbonylations

Organocatalysts supported on dendrimerized magnetic nanoparticles

The group members 1.Dr. Gilat Nizri 2.Dr. Saleh Abu-Lafi 3.Khali Hamza 4.Rony Schwarz 5.Suzana Natour 6.Suheir Omar 7.Amani Zoabi Thank you !