Organic compounds -- part of the class 532-570 series – Organic compounds – Oxygen containing
Reexamination Certificate
1999-01-14
2003-11-25
Lovering, Richard D. (Department: 1712)
Organic compounds -- part of the class 532-570 series
Organic compounds
Oxygen containing
C546S345000, C564S510000, C568S684000
Reexamination Certificate
active
06653512
ABSTRACT:
The present invention relates to perfluoroalkyl haloalkyl ether compounds, to compositions containing such compounds, and to the use of such compounds and compositions.
BACKGROUND
Chlorinated chemicals (e.g., chlorofluorocarbons, and hydrochlorofluorocarbons) have been used in the past as solvents within a number of specialized industrial applications. For instance, chlorinated chemicals are known to be useful within cleaning applications, including dry cleaning, wherein contaminated articles are washed (e.g., immersed in or otherwise contacted) to remove the contaminant. The chlorinated chemicals can be used as liquids or vapors, and at ambient or elevated temperatures (often in cleaning applications accompanied by ultrasonic agitation). Other applications wherein chlorinated chemicals are known to be useful include using chlorinated chemicals as coating or deposition solvents, for the removal of water from substrates, as a thermal media for heat transfer applications, as a blowing agent for polymeric foams, as a fire-extinguishing agent, and as a coolant/lubricant in metal working applications.
A major concern relating to the use of such chlorinated chemicals is the tendency (especially when used at an elevated temperature) for vapor loss into the atmosphere, causing pollution. Although care can be exercised to minimize such losses (e.g., through good equipment design and vapor recovery systems), most practical applications result in the loss of at least some vapor into the atmosphere.
Popular chlorinated chemicals that have been useful in the past (e.g., as cleaning solvents) include 1,1,2-trichloro-1,2,2-trifluoroethane and 1,1,1-trichloroethane. These are useful alone or in admixture with one or more co-solvents such as aliphatic alcohols or other low molecular weight polar compounds. These particular chlorinated compounds were initially believed to be environmentally benign, but have now been linked to depletion of the earth's ozone. According to the Montreal Protocol and its attendant amendments, production of such solvents has been discontinued in the U.S. (see, e.g., P. S. Zurer, “Looming Ban on Production of CFCs, Halons Spurs Switch to Substitutes,” Chemical & Engineering News, page 12, Nov. 15, 1993).
Thus, there has developed a need for substitutes or replacements for chlorinated chemicals that have been commonly used in the past. Such substitutes should exhibit one or more useful chemical or physical properties including a low ozone depletion potential, a boiling range suitable for solvent cleaning applications, and high solvency, i.e., the ability to readily dissolve or disperse organic and/or inorganic contaminants, such as water, hydrocarbon-based compounds, and fluorocarbon-based compounds. Preferably, substitutes will also be low in toxicity, have no measurable flash points (as determined by ASTM D3278-89), have acceptable thermal and chemical stability for use in a given application, and have short atmospheric lifetimes and low global warming potentials. Many compounds have been proposed as substitutes for such chlorinated compounds in a number of different uses and applications. Still, there remains a need for chemical compounds capable of replacing past commonly used chlorinated compounds and that exhibit one or more of such useful chemical or physical properties.
SUMMARY OF THE INVENTION
Perfluoroalkyl haloalkyl ether compounds have been discovered which can be useful by themselves and in chemical compositions for purposes including but not limited to use as solvents e.g., in cleaning processes such as dry cleaning processes, water removal processes, and in coating processes. The ethers have a haloalkyl component and a perfluorinated alkyl component, and exhibit useful and advantageous properties. These perfluoroalkyl haloalkyl ethers can exhibit, for example, one or more of the following physical or chemical properties useful boiling points, high solvency, acceptable toxicity properties, chemical and thermal stability, low ozone depletion characteristics, and preferably, substantially no flash point. Additionally, the presence of at least one hydrogen on the haloalkyl component allows for degradation of the compound, and reduces its long-term presence in the atmosphere.
An aspect of the invention relates to a chemical composition containing a perfluoroalkyl haloalkyl ether compound and a surfactant. The perfluoroalkyl haloakyl compound can be described generally by the formula:
R
f
—O—R
x
wherein R
f
is perfluoroalkyl and R
x
is haloalkyl. Preferred such compounds include those of the formula:
R
f
—O—C
x
H
y
F
w
X
z
wherein R
f
is a perfluoroalkyl preferably having at least about 3 carbons, most preferably from about 3 to 15 carbons, and optionally containing a catenary heteroatom such as N or O; x preferably is from about 1 to 6; y is at least one; w is in the range from 0 to about 2, X is a halogen chosen from bromine, iodine, and chlorine; z is at least one; and w+y+z is equal to 2x+1.
Another aspect of the invention relates to a process for removing contaminants from a substrate. The process includes the step of contacting the substrate with a composition comprising a perfluoroalkyl haloalkyl ether. The perfluoroalkyl haloalkyl ether can be of the formula:
R
f
—O—R
x
;
wherein R
f
is perfluoroalkyl and R
x
is haloalkyl. Preferred such compounds include those of the formula:
R
f
—O—C
x
H
y
F
w
X
z
wherein R
f
is a perfluoroalkyl preferably having at least about 3 carbons, most preferably from about 3 to 15 carbons, and optionally containing a catenary heteroatom such as N or O; x is from about 1 to 6; y is at least one; w is in the range from 0 to about 2, X is a halogen chosen from bromine, iodine, and chlorine; z is at least one; and w+y+z is equal to 2x+1.
Yet another aspect of the invention relates to perfluoroalkyl haloalkyl ethers, including n-C
3
F
7
OCH
2
Cl, n-C
3
F
7
OCHCl
2
, and those of the general formula:
R
f
—O—C
x
H
y
F
w
X
z
wherein R
f
is a perfluoroalkyl having at least 4 carbons and optionally containing a catenary heteroatom such as N or O; x is preferably from 1 to 2; y is at least one; w can be in the range from 0 to about 2, X is a halogen chosen from bromine, iodine, and chlorine; z is at least one; and w+y+z is equal to 2x+1. Specific such perfluoroalkyl haloalkyl ether compounds include those of the formulas c-C
6
F
11
OC
x
H
y
F
w
X
z
, c-C
6
F
11
CF
2
OC
x
H
y
F
w
X
z
, and C
4
F
9
OC
x
H
y
F
w
X
z
; specific compounds include C
4
F
9
OCH
2
Cl, C
4
F
9
OCHCl
2
, C
4
F
9
OCH
2
Br, C
4
F
9
OCH
2
I, C
4
F
9
OCHClCH
3
, and C
4
F
9
OCH
2
CH
2
Cl.
Yet another aspect of the invention relates to perfluoroalkyl haloalkyl ethers wherein the perfluoroalkyl component comprises a catenary nitrogen; i.e., wherein the perfluoroalkyl component comprises a perfluorinated amine. Ether-containing perfluorinated amines can be generally described by the formula:
(R
f
1
)(R
f
2
)NR
f
3
OR
x
wherein R
x
is a haloalkyl; R
f
1
and R
f
2
are independently straight or branched perfluoroalkyl groups preferably having from 1 to 6 carbons, or are independently straight or branched perfluoroalkyleile groups preferably having from 2 to about 4 carbons, the perfluoroalkylene groups being bonded to each other to form a ring, and R
f
3
is a linear or branched perfluoroalkylene preferably having from about 1 to 6 carbon atoms, wherein R
f
1
, R
f
2
and R
f
3
can optionally (and independently) contain one or more catenary heteroatoms. Preferably R
f
1
and R
f
2
, when perfluoroalkyl, have from 1 to about 3 carbon atoms, and when perfluoroalkylene have from 2 to 3 carbon atoms, R
f
3
preferably has from 1 to about 3 carbon atom. Also preferably, R
x
contains from 1 to about 6 carbons, more preferably from about 1 to 2 carbons.
As used within the present description when referring to the claimed perfluoroalkyl haloalkyl ethers, terms will be given the following meanings:
“haloalkyl” refers to an alkyl radical wherein at least one of the alkyl hydrogens has been replaced with a halogen chosen
Behr Frederick E.
Flynn Richard M.
3M Innovative Properties Company
Kokko Kent S.
Lovering Richard D.
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