Organic compounds -- part of the class 532-570 series – Organic compounds – Sulfonic acids or salts thereof
Patent
1998-09-04
2000-08-29
Geist, Gary
Organic compounds -- part of the class 532-570 series
Organic compounds
Sulfonic acids or salts thereof
562125, 562523, 562524, C07C30900
Patent
active
061111368
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a novel process for the preparation of perfluoroalkanecarboxylic acids and perfluoroalkanesulfonic acids.
Perfluoroalkanecarboxylic acids and perfluoroalkanesulfonic acids play an important role in the chemical industry of today ("Organof luorine Chemistry, Principles and Commercial Applications", R. E. Banks, B. E. Smart, J. C. Tatlow, Eds., Plenum Press, New York 1994).
Perfluoroalkanecarboxylic acids and perfluoroalkanesulfonic acids find a wide variety of uses in the chemical industry, both as synthetic intermediates and as finished products.
Long-chain perfluoroalkanecarboxylic acids and their salts are good surfactants which are able to reduce considerably the surface tension of water, of aqueous solutions and of organic liquids, even in low concentrations. These acids and their derivatives can also be used as emulsifiers, dispersing agents and foaming agents.
Short-chain perfluoroalkanesulfonic acids are used as intermediates in the preparation of sulfonamides. The latter are employed as plant growth regulators and as herbicides.
Perfluoroalkanesulfonic acids are also used as antistatic and antisoiling agents for porous substrates such as paper and textiles.
Methods for preparing perfluroalkanecarboxylic acids and perfluoroalkanesulfonic acids are already known. Thus, these acids are generally prepared either by electrochemical fluorination or by the use of chemical agents with strong oxidizing power. However, these methods each have their drawbacks.
The electrochemical fluorination technique is intricate and expensive because of the hazards associated with the use of liquid hydrogen fluoride and because of the corrosion of the electrolysis cells caused by the medium.
The oxidation routes using chemical agents comprise the action of hot oleum on perfluoroalkyl iodides. The use of oleum (very concentrated sulfuric acid containing sulfur trioxide, SO.sub.3) is also hazardous on account of its corrosive properties. Furthermore, this method results in partial degradation of the carbon chain, leading to the production of a mixture of homologous fluoro acids.
The process according to the present invention uses ozone for the preparation of perfluoroalkanecarboxylic acids and perfluoroalkanesulfonic acids. Ozone allows the starting materials to be oxidized mildly and selectively, thus overcoming the drawbacks and hazards associated with the methods of the prior art.
The subject of the present invention is thus a process for the preparation of perfluoroalkanecarboxylic acids and perfluoroalkanesulfonic acids, characterized in that ozone is reacted, in a protic medium, with a perfluoroalkyl chain containing at least one oxidizable chemical group.
The perfluoroalkyl chains which thus constitute the starting materials in the context of the present invention can contain 1 to 12 carbon atoms and have the general formula from: halogen and even more preferably iodine, or
According to a preferred embodiment, the sulfur-containing group is chosen from aryl thioethers, the aryl group being chosen from mono- or bicyclic radicals which can contain at least one substituent chosen from hydrogen, linear or branched alkyl radicals and halogen, ether, alkoxy, aryloxy, metal carboxylate, acyloxy, fluoroalkylthio, fluoroalkoxy and carboxylic acid radicals.
According to another preferred embodiment of the invention, the aromatic group is a mono- or bicyclic aromatic radical which can contain at least one substituent chosen from hydrogen, linear or branched alkyl radicals and halogen, ether, alkoxy, aryloxy, metal carboxylate, acyloxy, fluoroalkyl, fluoroalkoxy and carboxylic acid radicals.
In accordance with the process according to the invention, the reactions are carried out by simply placing the starting materials in contact with vapors containing ozone, which constitutes the most powerful oxidizing chemical element after fluorine, its standard oxidation potential relative to the standard hydrogen electrode being 2.07 V.
The reaction according to the present invention is carried out in protic medium.
REFERENCES:
patent: 4138417 (1979-02-01), Ukihashi et al.
patent: 4239696 (1980-12-01), Schreyer et al.
patent: 4324741 (1982-04-01), Umemoto et al.
patent: 4784809 (1988-11-01), Goldbaum et al.
patent: 4866190 (1989-09-01), Tordeux et al.
patent: 4925975 (1990-05-01), Aramaki et al.
patent: 5059711 (1991-10-01), Bielefeldt et al.
Berecibar Amaya
Marzouk Hatem
Petit Laurent
Tordeux Marc
Wakselman Claude
Centre National de la Recherche Scientifique
Electricite De France Service National
Geist Gary
Oh Taylor V
LandOfFree
Method for preparation of perfluoroalcanecarboxylic and perfluor does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for preparation of perfluoroalcanecarboxylic and perfluor, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for preparation of perfluoroalcanecarboxylic and perfluor will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1251548