published April 11, 2012
published July 1, 2011
UV-Resistant Amorphous Fluorinated Coating for Anodized Titanium Surfaces.
7th CoSI 2011 – Noordwijk
PDF VERSION
published July 25, 2010
published July 25, 2010
published June 18, 2010
published August 28, 2009
19th International Symposium on Fluorine Chemistry – Jackson Hole (USA) – August 23-28, 2009
Functionalization of Carbonaceous Materials with High Fluorine Content Organic Peroxides
M. Sansotera a, W. Navarrini a, P. Metrangolo a, G. Resnati a, C. Bianchi b, A. Guarda c
a Dip-CMIC ”Giulio Natta”, Politecnico di Milano, via Mancinelli 7, 20131 Milan, Italy;
b Department of Physical Chemistry and Electrochemistry, University of Milan, via Golgi 19, 20133, Milan, Italy
c R&D Centre, Solvay Solexis, viale Lombardia 20, 20021 Bollate (MI), Italy
E-mail: maurizio.sansotera@polimi.it
Perfluorodiacyl peroxides and perfluoropolyether peroxides (FOMBLIN peroxides) are suitable organic peroxides for direct linkage of perfluoroalkyl and perfluoropolyether chains on unsaturated substrates through a radical pathway. Highly graphitic carbon black and a-C:H diamond-like carbon are carbonaceous materials characterized by sp2 hybridized carbon atoms in the structure. Consequently a chemical treatment with high fluorine content organic peroxides allows the introduction of fluorinated groups onto carbonaceous substrates with carbon-carbon bond formation [1]. Depending on the peroxide involved during the treatment, several fluorinated chains, i.e. perfluoroethyl, CF3CF2-, perfluoro-n-propyl, CF3CF2CF2-, perfluoro-iso-propyl, (CF3)2CF-, and perfluoropolyether residual, has been covalently linked on the surface of such carbonaceous materials. Functionalization of carbon black transfers the typical hydrophobic properties of perfluorinated chains to the carbon black surface even preserving its conductive properties. This chemical treatment on diamond-like carbon films produces a covalently linked protective layers with the typical lubricant properties of perfluorinated compounds.
[1] Navarrini W., Sansotera M., Metrangolo P., Cavallotti P., Resnati G. WO 2009/019243 A1.
published September 25, 2008
2nd EuCheMS Chemistry Congress – 2008 September 16-20 – Torino, Italy
Simplified kinetic study of the reaction between perfluoro-methyl-hypofluorite and perfluoro-olefins
Navarrini Walter a*, Venturini Francesco a, Sansotera Maurizio a, Metrangolo Pierangelo a, Resnati Giuseppe a, Galimberti Marco b, Barchiesi Emma b, Dardani Patrizia b .
a Dipartimento di Chimica, Materiali e Ingegneria Chimica, Politecnico di Milano, 7, via Mancinelli, I-20131, Milano, Italy.
b Solvay-Solexis, R &D Centre, 20, viale Lombardia, I-20021 Bollate (MI), Italy.
In the reaction between perfluoroolefins and perfluoroalkylhypofluorites [1] the existence of two different free radical reaction mechanisms is demonstrated by the presence of characteristic by-products.
In particular in the reaction between trifluoromethyl hypofluorite and highly reactive perfluoroolefins like CF2=CFOCF3 and CF2=CF2, the free radical oligomerization and dimerization products can be suppressed by utilizing the opportune experimental conditions.
These experimental conditions are characterized by the presence of hypofluorite during the addition reaction and can be performed by adding the olefin to the hypofluorite, these conditions herein referred as ”Reverse hypofluorite addition” are different from the standard methodologies described in the literature where generally the hypofluorite is added to the olefin.
The main products of the addition of CF3OF to CF2=CFOCF3 are perfluoro-2,2-bis-(methoxy)-ethane and perfluoro-1,3-bis-(methoxy)-ethane [2] in the molar ratio of 20% and 80% respectively.
We found experimental evidence for the termination products peroxide CF3OOCF3 and perfluoroethersC8F18O4respectively. The first termination product CF3OOCF3 was present at high amount in the reaction where the CF3OF concentration was maintained always above zero and substantially constant, on the contrary the termination products C8F18O4 were completely absent. In this conditions the oligomerization and polymerization of the perfluoroolefins were also suppressed, as well as in the case of the very reactive TFE.
[1] W. Navarrini, V. Tortelli, A. Russo, S. Corti, J. Fluorine Chem. 95(2),(1999)27-39.
[2] W. Navarrini, G. Resnati, P. Metrangolo, M. Cantini, F. Venturini, IT Patent app. MI2007A001384 (2007).
RELATED POSTER
published September 20, 2008
published September 23, 2007
posted in Posters
15th European Symposium on Fluorine Chemistry – Prague – July 15-20, 2007
New Advances in Perfluoroalkytation of Aromatics: Products and Mechanism
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
E-mail: maurizio.sansotera@polimi.it; walter.navarrini@polimi.it
Thermal decomposition of perfluorodiacyl peroxides in the presence of aromatic compounds leads to the synthesis of perfluoroalkylated aromatic derivatives. C3 and C4-perfluorodiacyl peroxides have been synthesized starting from C3 and C4-perfluoroacyl halides with H2O2 in alkaline conditions and have been employed in reactions with several aromatic substrates. The capability of perfluorodiacyl peroxides to generate perfluoroalkyl free radicals is at the basis of the perfluoroalkylation process. Perfluoroalkyl radical reacts with the aryl via an electron-transfer propagation process. During the formation of the perfluoroalkylated intermediate the aromatic substrate loses its aromaticity and another molecule of peroxide oxidizes the intermediate. Finally a proton removal restores the aromaticity. Competitive mechanistic pathways are responsible for the perfluoroalkyl radical formation: primarily the concerted dissociation with a three-bond fission, and secondarily the stepwise decomposition through primary homolytic cleavage of O-O peroxidic bond and subsequent decarboxylation. Stability of the oncoming radicals and temperature are the important parameters to discriminate the decomposition pathway. The analyses of reaction main-products and by-products allowed to draw a more complete mechanism pathway that can be applied to the whole family of aromatic compounds.
published August 9, 2006
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