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POLITECNICO DI MILANO M. Sansotera a, P. Metrangolo a, W. Navarrini a, G. Resnati a, I. Wlassics b a Dip-CMIC Giulio Natta, Politecnico di Milano, via.

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Presentation on theme: "POLITECNICO DI MILANO M. Sansotera a, P. Metrangolo a, W. Navarrini a, G. Resnati a, I. Wlassics b a Dip-CMIC Giulio Natta, Politecnico di Milano, via."— Presentation transcript:

1 POLITECNICO DI MILANO M. Sansotera a, P. Metrangolo a, W. Navarrini a, G. Resnati a, I. Wlassics b a Dip-CMIC Giulio Natta, Politecnico di Milano, via Mancinelli 7, 20131 Milan, Italy b R&D Centre, Solvay Solexis, viale Lombardia 20, 20021 Bollate (MI), Italy 15th European Symposium on Fluorine Chemistry 15-20 July 2007, Prague, Czech Republic SOLVAY - SOLEXIS New Advances in Perfluoroalkytation of Aromatics: Products and Mechanism

2 PERFLUOROALKYLATION STRATEGIES NUCLEOPHILIC ATTACK ON PERFLUOROALKENES

3 PERFLUOROALKYLATION STRATEGIES NUCLEOPHILIC ADDITION - Organometallic Reagents, R F Zn or R F Li - Trifluoromethylation with CF 3 Si(CH 3 ) 3

4 PERFLUOROALKYLATION STRATEGIES ELECTROPHILIC PERFLUOROALKYLATION FITS

5 PERFLUOROALKYLATION STRATEGIES - Iodoperfluorocompound in presence of peroxidic agent - Perfluoroalkylsulfonyl chloride catalyzed by Ru - Perflurodiacyl Peroxide FREE RADICAL

6 SYNTHESIS OF PERFLUORODIACYL PEROXIDES Preparation of PERFLUORODIACYL PEROXIDES [1] Perfluorodi-n-butyryl Peroxide Yield 50% Perfluorodi-iso-butyryl Peroxide Yield 70% Perfluorodipropionyl Peroxide Yield 30% [1] W. Navarrini, M. Galimberti, E. Barchiesi J.F.C. 2005, 126, 587

7 CHARACTERIZATION PERFLUORODIACYL PEROXIDES FT-IR 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 %T 1858 cm -1 1830 cm -1 1500 2000 Wavenumbers (cm-1) 1856 cm -1 1827 cm -1 1500 2000 1500 2000 1860 cm -1 1831 cm -1 19 F-NMR ppm Solvent Peaks

8 k d x 10 5 (s –1 ) DECOMPOSITION OF PERFLUORODIACYL PEROXIDES Decomposition kinetics [2] of PERFLUORODIACYL PEROXIDES [2] M. Sansotera, C. Corvaja, A. Famulari, L. Franco, M. Galimberti, P. Metrangolo, W. Navarrini, G. Resnati ChemToday 2006, 24, 3, 17 3,7 2,5 30 5,3 7,8 Peroxide T (°C) t 1/2 (h) 60 4,4

9 SOURCES OF PERFLUORINATED RADICALS EPR-characterization of PERFLUORORADICALS J = 87,7 Gauss J = 70,2 GaussJ = 86,4 Gauss -- Experimental -- Calculated T = 40 °C T = 60 °CT = 40 °C

10 SOURCES OF PERFLUORINATED RADICALS Quantum mechanic calculations [2] for the study of the structures of PERFLUORORADICALS [2] M. Sansotera, C. Corvaja, A. Famulari, L. Franco, M. Galimberti, P. Metrangolo, W. Navarrini, G. Resnati ChemToday 2006, 24, 3, 17 The electronic structures have been investigated at the DFT-B3LYP level by means of the GAMESS-US program with the 6-311G** basis set. Distortion from the Planarity in perfluoroethyl radical 25° Distortion from the Planarity in perfluoro-iso-propyl radical 5°

11 PERFLUOROALKYLATION OF AROMATIC SUBSTRATES 86% 95%97% Ar-HProduct Yields 96% (4%) a 89% (4%) a 69% (31%) a a Yields of benzylic by-products. 64% 39% 68%

12 MECHANISM FROM LITERATURE Mono-electronic transfer process [3] Formation of products [3] H.Sawada, Chem. Rev. 1996, 96, 1779

13 PERFLUOROALKYLATION MECHANISM Thermolytic Initiation Electron Transfer Propagation Carbocation Aromatization

14 MECHANISM OF SECONDARY REACTION Hydrogen Abstraction Benzyl Radical Induced Decomposition

15 CONCLUSIONS A procedure for the synthesis and characterization of perfluorodiacyl peroxides has been developed. EPR analyses demonstrated they are source of perfluorinated radicals. Quantum mechanics calculations and EPR analyses in substantial agreement corroborate the deviation from planarity as important factor of the stabilizing effect of substituents on the radical center. Perfluorodiacyl peroxides have been used to perfluoroalkylate different aromatic substrates and for this reaction a mechanism for products and by-products has been proposed.

16 ACKNOWLEDGMENTS Politecnico di Milano Dr. S. Biella Dr. F. Meyer Dr. F. Chaux Dr. G. Terraneo Dr. A. Famulari Mr. M. Ursini Mr. F. Venturini Ms. M. Bonacina Mr. A. Marcon Solvay Solexis – S.p.a. Dr. M. Galimberti Dr. S. Radice Dr. E. Barchiesi Mr. G. Ciocca Università degli Studi di Padova Prof. C. Corvaja Dr. L. Franco Politecnico di Milano Solvay Solexis – S.p.a. Università degli Studi di Padova


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