Recent developments in the chemistry of organic perfluoro hypofluorites.

Author(s): VENTURINI F., SANSOTERA M., NAVARRINI W.

Source: Journal of Fluorine Chemistry

Volume: 155 Pages: 2-20

DOI: 10.1016/j.jfluchem.2013.07.005 (2013)

ABSTRACT:

Recent findings in the synthesis of perfluoro-hypofluorites, their reactivity and their use in the preparation of important perfluoro monomers are herein summarized and analyzed. The experimental conditions to induce free radical or electrophilic reactivity as well as their use as initiation system in the oxidation and oxypolimerization of fluorinated olefins are also presented. Particular emphasis is dedicated to safety issues since organic hypofluorites have the tendency to self-decompose forming gaseous compounds.The hypofluorites considered in this review are: CF3OF, CF2(OF)2, CF3CF2OCF2OF, CF3OCF2CF2OCF2OF, CF3O(CF2O)nCF2OF, CF3OCF2CF2OF, (CF3)2CFOF (CF3)3COF, FS(O)2CF2CF2OF, CF3OCF2CF2CF2OF, cyclo-(CF2OCF2OCF)-CF2OF, (CF3)2N-CF2OF.

http://www.sciencedirect.com/science/article/pii/S0022113913002601

Direct fluorination of carbon monoxide in microreactors.

Author(s): NAVARRINI W., VENTURINI, F., TORTELLI V., BASAK S., PIMPARKAR K. P., ADAMO A., JENSEN K. F. Source: Journal of Fluorine Chemistry. Volume: 142 Pages: 19-23. DOI: 10.1016/j.jfluchem.2012.06.006. Published: Oct (2012). ABSTRACT:

Many attempts to obtain a clean stream of COF2 have been carried out in the past by means of the direct fluorination of carbon monoxide with elemental fluorine or by electrochemical fluorination. The reaction is highly exothermic, therefore difficult to control. It can easily develop into a thermal runaway with a poor selectivity. We have successfully circumvented these critical issues by using a stainless steel parallel channel microreactor (surface/volume ratio approximate to 1 x 104 m(-1), residence time T approximate to 0.1 s) for the direct fluorination of carbon monoxide. Its performance in terms of operability and selectivity is compared to that of a standard reactor assembly, namely a fluorine burner reactor coupled with a water cooled heat exchanger. While the microreactor assembly succeeded to control the exothermic reaction, in the same experimental conditions the standard assembly reactor underwent serious corrosion issues that lead to nozzle meltdown lack of selectivity and consequent plant shutdowns. http://www.sciencedirect.com/science/article/pii/S0022113912001790

Direct trifluoro-methoxylation of aromatics with perfluoro-methyl-hypofluorite.

Author(s): VENTURINI F., NAVARRINI W., FAMULARI A., SANSOTERA M., DARDANI P., TORTELLI V.

Source: Journal of Fluorine Chemistry.

Volume: 140 Pages: 43-48.

DOI: 10.1016/j.jfluchem.2012.04.008.

Published: Aug (2012).

ABSTRACT:

The reactivity of CF3OF (FM) has been widely studied especially in halogenated olefinic systems and its use in pharmaceutical synthesis as a mild radical and electrophilic fluorinating agent is well documented. On the other hand, the chemical behavior of the perfluoro-methyl-hypofluorite with aromatic substrates is much less studied. Up to now few and scattered data regarding its use as electrophilic fluorinating agent of variously substituted aromatic compounds are found in the literature. In this work the reactivity of CF3OF with simple electron rich and electron poor aromatics (alpha,alpha,alpha-trifluoro-toluene, toluene. benzene, chloro-benzene, methoxybenzene) has been investigated. The possibility of selectively bind the trifluoro-methoxy group (via radical mechanism) or the fluorine atom (via electrophilic addition) by varying the reaction conditions has been explored. In particular we have observed that the trifluoromethoxy free radical substitution can be the main synthetic pathway if the reaction is promoted by an independent and steady source of CF3O radical. http://www.sciencedirect.com/science/article/pii/S0022113912001145

Process for Preparing Ionomeric Membranes

US Patent: 7704639 B2

Date: Apr. 27, 2010

Inventors: W. Navarrini, S. Panero, B. Scrosati, A. Sanguineti

US7704639B2 – PDF

Fluorovinyl Ethers and Polymers Obtainable Therefrom

US Patent: 7534845 B2

Date: May 19, 2009

Inventor: W. Navarrini

US7534845B2 – PDF

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

Reactions under Novel Conditions: Simplified Kinetic Study of the Reaction between Perfluoro-Methyl-Hypofluorite and Perfluoro-Olefins: CF3OF + CF3OCF=CF2 -> CF3OCF2CF2OCF3 + (CF3O)2CFCF3

2nd EuCheMS Chemistry Congress – Torino 2008

PDF VERSION

FLUO 34-Synthesis of low Ostwald coefficient perfluorinated ethers by the exploit of perfluoroalkyl hypofluorites.

Author(s): Navarrini, Walter; Venturini, Francesco; Sansotera, Maurizio; Metrangolo, Pierangelo; Resnati, Giuseppe; Galimberti, Marco; Tortelli, Vito.

Source: ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY

Volume: 236

Meeting Abstract: 34-FLUO Published: AUG 17 2008

ABSTRACT:

The addiction reaction of hypofluorite to halogenated olefins has been studied in the past. In our previous studies we have noticed that the concentration of hypofluorite in the reaction media is an important variable to control the course of the main reaction. This experimental approach allowed the identification of a straight and economical methodology for the preparation of highly pure perfluoroethers with low boiling point and low Ostwald coefficient. These perfluoroethers have been recently tested as fluids for the preparation of injectable microbubble compositions as contrast agents in diagnostic ultrasound imaging. In many ultrasounds imaging applications there is the need for more efficient contrast agents and efforts to develop suitable materials are ongoing.

Addition of perfluoroolefins to trifluoromethyl hypofluorite for the preparation of low molecular weight perfluorinated oxygen containing fluids kinetics and byproducts.

Author(s): VENTURINI F., METRANGOLO P., RESNATI G., NAVARRINI W., TORTELLI V.

Source: Chimica Oggi – Chemistry Today.

Volume: 26 Pages: 36-38. Published: Aug. (2008).

ABSTRACT:

The products deriving from the addition of CF2=CFOCF3 to CF3OF are proved to be low Ostwald coefficient fluids suitable for producing high stable micro bubbles that can be used as ultrasound imaging contrast agents. The standard gas-liquid fast radical chain reaction between trifluoromethyl hypofluorite CF3OF and reactive perfluoroolefins like CF2=CFOCF3produces oligomerization and dimerization byproducts. Therefore a purification procedure is needed in order to separate the low Ostwald coefficient products from the reaction mixture. Surprisingly we have found that the selectivity of the reaction can be increased by modifying the experimental reaction conditions adopted. This behaviour is an experimental evidence for the presence of two different reaction schemes that can be switched by tuning the hypofluorite concentration in the reaction media.

The use of perfluoroalkyl hypofluorites for an efficient synthesis of perfluorinated ethers characterized by low Ostwald coefficient.

Author(s): NAVARRINI W., VENTURINI F., SANSOTERA M., URSINI M., METRANGOLO P., RESNATI G., GALIMBERTI M., BARCHIESI E., DARDANI P.

Source: Journal of Fluorine Chemistry.

Volume: 129 Issue: 8 Pages: 680-685.

DOI: 10.1016/j.jfluchem.2008.05.018. Published: Aug. (2008).

ABSTRACT:

In the reaction between perfluoroolefins and perfluoroalkylhypofluorites the existence of two different free radical reaction mechanisms is demonstrated by the presence of characteristic byproducts. These kinetic schemes can be experimentally controlled by tuning the hypofluorite concentration in the reaction media. In particular, in the reactions between trifluoromethyl hypofluorite and highly reactive perfluoroolefins like CF2CFOCF3 and CF2CF2, the free radical oligomerization and dimerization products can be suppressed by utilizing the opportune experimental conditions. The pure perfluorinated ethers obtained, having low Ostwald coefficient, can be utilized as contrast agents for diagnostic ultrasound imaging injectable microbubbles composition.

http://www.sciencedirect.com/science/article/pii/S0022113908001486

Polyhalogenated Ethers

US Patent: 7393961 B2

Date: Jul. 1, 2008

Inventors: G. Fontana, W. Navarrini

US7393961B2 – PDF

Process for the Preparation of (Per)Fluorinated Mono-Functional Carbonyl Compounds

US Patent: 7375253 B2

Date: May 20, 2008

Inventors: G. Fontana, W. Navarrini

US7375253B2 – PDF

Process for the Preparation of (Per) Fluorinated Mono-Functional Carbonyl Compounds

US Patent: 7321062 B2

Date: Jan. 22, 2008

Inventors: G. Fontana, W. Navarrini

US7321062B2 – PDF

Fluorovinyl Ethers and Polymers Obtainable Therefrom

US Patent: 7160967 B2

Date: Jan. 9, 2007

Inventor: W. Navarrini

US7160967B2 – PDF

Process for Preparing Hydrofluoroethers

US Patent: 7141704 B2

Date: Nov. 28, 2006

Inventors: W. Navarrini, M. Galimberti, G. Fontana

US7141704B2 – PDF