Coating processes – Miscellaneous
Reexamination Certificate
2001-02-20
2002-12-10
Webb, Gregory E. (Department: 1751)
Coating processes
Miscellaneous
C510S412000, C106S002000
Reexamination Certificate
active
06491983
ABSTRACT:
This invention relates to omega-hydrofluoroalkyl ethers and their preparation and application. In another aspect, this invention relates to perfluoro(alkoxyalkanoic) acids and derivatives thereof and their preparation. In another aspect, it relates to the preparation of perfluoro(alkoxyalkanoic) acids by direct fluorination of their hydrocarbon alkanoic acid or ester analogs and to the preparation of omega-hydroflouroalkyl ethers, for example, by decarboxylation of said acids or their alkyl esters. In another aspect, this invention relates to uses of perfluoro(alkoxyalkanoic) acids and derivatives thereof.
Because of a steady flow of bad news about the damaged stratospheric ozone layer, the deadlines for the end to industrialized countries' production of chlorofluorocarbons (“CFCs”) and other ozone-depleting chemicals were accelerated by countries who are parties to the Montreal Protocol on Substances That Deplete the Ozone Layer—see Zurer, P. S., “Looming Ban on Production of CFCs, Halons Spurs Switch to Substitutes,” Nov. 15, 1993,
Chemical
&
Engineering News,
p. 12.
Work is under way to replace CFCs and halons, such as CCl
2
F
2
, CCl
3
F, CF
3
Br, and CCl
2
FCClF
2
, with substitute or alternative compounds and technologies. A number of hydrofluorocarbons (“HFCs”), e.g., CH
2
FCF
3
(“HFC-134a”), are being used or have been proposed as CFC substitutes (and HFC-134a has been characterized as being more “ozone friendly”—see U.S. Pat. No. 5,118,494 (Schultz et al.)). Hydrochlorofluorocarbons (“HCFCs”), such as CH
3
CCl
2
F (“HCFC-141b), as the
C
&
EN
article, sura, points out, are CFC substitutes, but although they are not nearly as damaging, these substitutes do carry ozone-depleting chlorine into the stratosphere. Another proposed substitute is the simple omega-hydrodifluoromethyl perfluoromethyl ether, CF
3
OCF
2
H—See J. L Adcock et.al., “Fluorinated Ethers—A new Family of Halons,” 1991 CFC Conference Proceedings (1991). Another hydro-fluoroalkyl ether (or ether hydride), F[CF(CF
3
)CF
2
O]
4
CFHCF
3
, made by decarboxylation of the fluorinated 2-alkoxypropionic acid salt, has been tested as a blood emulsion—see
Chem. Pharm. Bull.
33, 1221 (1985).
U.S. Pat. No. 4,173,654 (Scherer) states that fluorocarbons due to their inertness have found use as electronic coolant or leak testing fluids, and other compounds having good solubility for oxygen have been investigated as artificial blood substitutes. This patent describes certain fluorocarbon “hybrid” materials with metabolically active hydrocarbon moieties, such as, inter alia, —CH
2
—(CH
2
)
m
—H. U.S. Pat. No. 4,686,024 (Scherer et al.), which describes certain perfluorocyclic ethers, states that various perfluoro chemicals are disclosed in patents as being suitable as oxygen and carbon dioxide carriers. And International Application published as WO 93/11868 (Kaufman et al.) describes certain chlorofluorochemicals and emulsions thereof as useful in various oxygen transport applications, e.g., as oxygen transfer agents or “artificial bloods.”
There are a number of other patents describing various fluorocarbon ethers or polyethers. U.S. Pat. No. 3,342,875 (Selman et al.) describes certain “hydrogen modified fluorocarbon ethers” (or “hydrogen capped polyethers”) made, inter alia, by pyrolysis of a hydrogen-containing derivative of an ether, such as the fluorocarbon ether acid or the ammonium salt, which ether is obtained by the polymerization of fluorocarbon epoxides. British Patent Specification 1,194,431 (Montecatini Edison S.P.A.) describes certain perfluorinated ethers and polyether derivatives having the general formula
CF
3
—O—(C
3
F
6
O)
M
—(CF
2
O)
N
—(CF(CF
3
)—O)
L
—CF
2
X
where, inter alia, each subscript M, N, and L is zero or a whole number from 1 to 99, and X is a hydrogen atom or —COOMe wherein Me is an equivalent of an alkali or alkaline earth metal, an examples of which is pentafluorodimethyl ether, CF
3
—O—CF
2
H.
U.S. Pat. No. 3,597,359 (Smith) describes certain perfluoroalkylene ether-containing compound represented by the formula
wherein, inter alia, R is alkylene, alkoxyalkylene, or perfluoroalkylene, R
1
is fluorine or trifluoromethyl provided not more than one R
1
is trifluoromethyl, R
2
is fluorine or trifluoromethyl provided not more than one R
2
is trifluoromethyl, R
3
is fluorine or trifluoromethyl, R
4
is hydrogen or halogen provided that when R is alkylene or alkoxyalkylene R
4
is hydrogen, R
5
is perfluoroalkylene having at least 2 carbon atoms, R
6
is, inter alia hydrogen, trifluoromethyl or perfluoroethyl, a is zero or 1, n and m are whole numbers of 0 to 50, and n+m is 1 to 50.
U.S. Pat. No. 3,962,460 (Croix et al.) describes aliphatic ethers, including those of the formulas
International Patent Application WO 90/01901 (Long) describes certain perfluorocarbon hydrides, such as perfluorooctyl hydride, used in emulsions for carrying oxygen to the tissues of an animal body. European Patent Application Publication No. 0 482 938 A1 (Chambers et al.) describes fluorinated ethers of the formula
wherein R is hydrogen, fluorine, or alkyl or fluoroalkyl of 1-6 carbon atoms, R′ is hydrogen or alkyl or fluoroalkyl of 1 to 6 carbon atoms, and R″ is fluorine or alkyl or fluoroalkyl of 1 to 6 carbon atoms.
Other patents describing one or more various fluoroalkoxyalkanoic acids and esters or other derivatives thereof and their preparation are U.S. Pat. No. 2,713,593 (Brice et al.), U.S. Pat. No. 3,214,478 (Milian, Jr.), U.S. Pat. No. 3,393,228 (Braun), U.S. Pat. No. 4,118,421 (Martini), U.S. Pat. No. 4,357,282 (Anderson et al.), U.S. Pat. No. 4,729,856 (Bernonge), U.S. Pat. No. 4,847,427 (Nappa), U.S. Pat. No. 4,940,814 (Schwertfeger), U.S. Pat. No. 4,973,716 (Calini et al.), U.S. Pat. No. 5,053,536 (Bierschenk et al.) U.S. Pat. No. 5,093,432 (Bierschenk et al.), and U.S. Pat. No. 5,118,494 (Schultz et al.) and PCT International Applications Pub. Nos. WO 90/03357 (Moore et al.) and WO 90/06296 (Costello et al.). The aforementioned Brice et al. patent describes fluorocarbons acids made by electrochemical fluorination including an acid having a boiling point of 225° C. and said to be n-C
8
F
17
OC
2
F
4
CO
2
H. The aforementioned Nappa, Bierschenk et al., Moore et al., and Costello et al. publications describe the preparation of the fluorinated compounds by direct fluorination of hydrocarbon analog precursors.
In one aspect, this invention provides a normally liquid (i.e., liquid under ambient conditions of temperature and pressure) fluoroalkyl ether compound or a normally liquid composition consisting or consisting essentially of a selected mixture of such compounds, said compound having a saturated perfluoroaliphatic chain of carbon atoms (e.g., 4 to 30) interrupted by one or a plurality (e.g., 2 to 8) of ether (or catenary, i.e., in-chain) oxygen atoms. The chain carbon atom at one end (hereafter called the proximal end) of the chain is bonded to a hydrogen atom (i.e., an omega-hydro substituent, or primary hydrogen atom) and two fluorine atoms, said proximal carbon atom being the carbon atom of a difluoromethyl group or moiety, —CF
2
H, which is directly bonded to another chain carbon atom, such as that of perfluoroalkylene chain segment, —C
N
F
2N
, or to a said ether-oxygen. The carbon atom at the other end of the chain (the distal end) is part of a distal group selected from the group consisting of a difluoromethyl, a difluorochloromethyl, —CF
2
Cl, a perfluoroalkyl substituted with a saturated alicyclic moiety, e.g., c—C
6
F
11
—, a straight-chain perfluoroalkyl, and a branched chain perfluoroalkyl. In a said compound where said proximal end of the chain terminates in a difluoromethyl group bonded to an ether-oxygen atom, then said straight-chain perfluoroalkyl has at least 6 chain carbon atoms, e.g., 6 to 16 chain carbon atoms, and said branched-chain perfluoroalkyl has at least 4 carbon atoms, e.g., 4 to 16 carbon atoms. Examples of such omega-hydro fluoroalkyl ether compounds are:
If a said “selected mixture,” i.e., a predetermined mixture of sel
Flynn Richard M.
Guerra Miguel A.
Moore George G. I.
Owens John G.
3M Innovative Properties Company
Ewert William
Webb Gregory E.
Weiss Lucy C.
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