US4894484A
Expired / Lapsed
US
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Pyrolysis of perfluoropolyethers
Assignee: Exfluor Research Corp
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Filing: 1987-09-03
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Granted: 1990-01-16
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Expires: 2007-09-03
Abstract
Abstract A method of breaking down perfluoropolyethers into lower molecular weight fragments by pyrolysis is disclosed. The perfluoropolyethers are pyrolyzed generally at above about 350° C. Volatile lower molecular weight components are condensed and collected. Various molecular weight fractions can be obtained by taking appropriate distillation cuts.
Inventors
- 👤 Richard J. Lagow
- 👤 Thomas R. Bierschenk
- 👤 Timothy J. Juhlke
- 👤 Hajimu M. Kawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 22:54
CPC Classifications
C; C08; C08G; C08G65/00; C08G65/002; C08G65/005; C08G65/007; C08G65/02; C08G65/32
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
80 words
A method of cleaving perfluoropolyethers to lower molecular weight fragments, comprising the steps of: (a) providing a perfluoropolyether selected from the group consisting of perfluoropoly(ethylene oxide), perfluoropolypropylene oxide, perfluoroethylene oxide/methylene oxide/copolymers, perfluoroethylene oxide/propylene oxide copolymers, perfluoropoly(tetramethylene oxide) and perfluoropoly(cyclohexyl oxide); (b) pyrolyzing the perfluoropolyether at a temperature above about 350° C. to cleave the perfluoropolyether into lower molecular weight perfluoropolyethers in the absence of a metal oxide or metal fluoride catalyst; and (c) condensing and collecting lower molecular weight perfluoropolyethers.
Claim 2
Independent Claim
80 words
A method of cleaving perfluoropolyethers to lower molecular weight fragments, comprising the steps of: (a) providing a perfluoropolyether selected from the group consisting of perfluoropoly(ethylene oxide), perfluoropolypropylene oxide, perfluoroethylene oxide/methylene oxide/copolymers, perfluoroethylene oxide/propylene oxide copolymers, perfluoropoly(tetramethylene oxide) and perfluoropoly(cyclohexyl oxide); (b) pyrolyzing the perfluoropolyether at a temperature above about 350° C. to cleave the perfluoropolyether into lower molecular weight perfluoropolyethers in the absence of a metal oxide or metal fluoride catalyst; and (c) condensing and collecting lower molecular weight perfluoropolyethers.
Claim 3
Dependent Claim
31 words
A method of claim 1, further comprising the step of: d. treating the collected perfluoropolyethers with fluorine gas to eliminate acyl fluoride end groups and any unsaturation of the collected perfluoropolyethers.
Claim 4
Dependent Claim
17 words
A method of claim 1, wherein the perfluoropolyether is pyrolyzed in the presence of an inert gas.
Claim 5
Dependent Claim
25 words
A method of claim 1, wherein the perfluoropolyether is pyrolyzed in the presence of fluorine gas or a mixture of inert gas and fluorine gas.
Claim 6
Dependent Claim
13 words
A method of claim 1, wherein the pyrolysis is performed at ambient pressure.
Claim 7
Dependent Claim
32 words
A method of claim 1, wherein the pyrolysis is performed at a pressure above ambient pressure to produce perfluoropolyether fragments of a lower average molecular weight than those produced at ambient pressure.
Claim 8
Dependent Claim
32 words
A method of claim 1, wherein the pyrolysis is performed at a pressure below ambient pressure to produce perfluoropolyether fragments of a higher average molecular weight than those produced at ambient pressure.
Claim 9
Dependent Claim
15 words
A method of claim 1 wherein the lower molecular perfluoropolyether of step c is linear.
Claim 10
Independent Claim
154 words
A method of breaking down perfluoropolyethers into lower molecular weight polymers, comprising the steps of: (a) providing a distillation apparatus comprising: (i) a sample vessel located in a heating zone; (ii) a condensing zone; (iii) a collection vessel connected by passageway to the condensing zone; and (iv) means for introduction of a gas; (b) placing a perfluoropolyether in the sample vessel wherein the perfluoropolyether is selected from the group consisting of perfluoropoly(ethylene oxide), perfluoropolypropylene oxide, perfluoroethylene oxide/methylene oxide/ copolymers, perfluoroethylene oxide/propylene oxide copolymers, perfluoropoly(tetramethylene oxide) and perfluoropoly(cyclohexyl oxide); (c) establishing a flow of inert gas into the apparatus; (d) heating the perfluoropolyether by raising the temperature of the heating zone to above 350° C. in the absence of a metal oxide or metal fluoride catalyst; (e) maintaining the temperature in the heating zone to vaporize the lower molecular weight fragment of the perfluoropolyether; and (f) collecting condensed lower molecular weight fragments of the perfluoropolyether.
Claim 11
Independent Claim
154 words
A method of breaking down perfluoropolyethers into lower molecular weight polymers, comprising the steps of: (a) providing a distillation apparatus comprising: (i) a sample vessel located in a heating zone; (ii) a condensing zone; (iii) a collection vessel connected by passageway to the condensing zone; and (iv) means for introduction of a gas; (b) placing a perfluoropolyether in the sample vessel wherein the perfluoropolyether is selected from the group consisting of perfluoropoly(ethylene oxide), perfluoropolypropylene oxide, perfluoroethylene oxide/methylene oxide/ copolymers, perfluoroethylene oxide/propylene oxide copolymers, perfluoropoly(tetramethylene oxide) and perfluoropoly(cyclohexyl oxide); (c) establishing a flow of inert gas into the apparatus; (d) heating the perfluoropolyether by raising the temperature of the heating zone to above 350° C. in the absence of a metal oxide or metal fluoride catalyst; (e) maintaining the temperature in the heating zone to vaporize the lower molecular weight fragment of the perfluoropolyether; and (f) collecting condensed lower molecular weight fragments of the perfluoropolyether.
Claim 12
Independent Claim
93 words
A method of cleaving perfluoropolyether solids to produce perfluoropolyether oils, comprising the steps of: (a) providing a solid perfluoropolyether selected from the group consisting of perfluoropoly(ethylene oxide), perfluoropolypropylene oxide, perfluoroethylene oxide/methylene oxide/copolymers, perfluoroethylene oxide/propylene oxide copolymers, perfluoropoly(tetramethylene oxide) and perfluoropoly(cyclohexyl oxide); (b) heating the solid perfluoropolyether to a temperature above about 350° C. for a period of time sufficient to cleave the perfluoropolyether into lower molecular weight fragments in the absence of a metal oxide or metal fluoride catalyst; and (c) condensing and collecting vaporized lower molecular weight fragments to obtain an oil.
Claim 13
Independent Claim
93 words
A method of cleaving perfluoropolyether solids to produce perfluoropolyether oils, comprising the steps of: (a) providing a solid perfluoropolyether selected from the group consisting of perfluoropoly(ethylene oxide), perfluoropolypropylene oxide, perfluoroethylene oxide/methylene oxide/copolymers, perfluoroethylene oxide/propylene oxide copolymers, perfluoropoly(tetramethylene oxide) and perfluoropoly(cyclohexyl oxide); (b) heating the solid perfluoropolyether to a temperature above about 350° C. for a period of time sufficient to cleave the perfluoropolyether into lower molecular weight fragments in the absence of a metal oxide or metal fluoride catalyst; and (c) condensing and collecting vaporized lower molecular weight fragments to obtain an oil.
Claim 14
Independent Claim
70 words
A method of cleaving perfluoropolyethers to lower molecular weight fragments, comprising the steps of: (a) providing a perfluoropolyether selected from the group consisting of perfluoropoly(ethylene oxide), perfluoropolypropylene oxide, perfluoroethylene oxide/methylene oxide/copolymers, perfluoroethylene oxide/propylene oxide copolymers, perfluoropoly(tetramethylene oxide) and perfluoropoly(cyclohexyl oxide); (b) pyrolyzing the perfluoropolyether at a temperature from about 500° C.-600° C. to cleave the perfluoropolyether into lower molecular weight perfluoropolyethers; and (c) condensing and collecting lower molecular weight perfluoropolyethers.
Claim 15
Independent Claim
70 words
A method of cleaving perfluoropolyethers to lower molecular weight fragments, comprising the steps of: (a) providing a perfluoropolyether selected from the group consisting of perfluoropoly(ethylene oxide), perfluoropolypropylene oxide, perfluoroethylene oxide/methylene oxide/copolymers, perfluoroethylene oxide/propylene oxide copolymers, perfluoropoly(tetramethylene oxide) and perfluoropoly(cyclohexyl oxide); (b) pyrolyzing the perfluoropolyether at a temperature from about 500° C.-600° C. to cleave the perfluoropolyether into lower molecular weight perfluoropolyethers; and (c) condensing and collecting lower molecular weight perfluoropolyethers.
Claim 16
Independent Claim
144 words
A method of breaking down perfluoropolyethers into lower molecular weight polymers, comprising the steps of: (a) providing a distillation apparatus comprising: (i) a sample vessel located in a heating zone; (ii) a condensing zone; (iii) a collection vessel connected by passageway to the condensing zone; and (iv) means for introduction of a gas; (b) placing a perfluoropolyether in the sample vessel wherein the perfluoropolyether is selected from the group consisting of perfluoropoly(ethylene oxide), perfluoropolypropylene oxide, perfluoroethylene oxide/methylene oxide/ copolymers, perfluoroethylene oxide/propylene oxide copolymers, perfluoropoly(tetramethylene oxide) and perfluoropoly(cyclohexyl oxide); (c) establishing a flow of inert gas into the apparatus; (d) heating the perfluoropolyether by raising the temperature of the heating zone from about 500° C.-600° C.; (e) maintaining the temperature in the heating zone to vaporize the lower molecular weight fragment of the perfluoropolyether; and (f) collecting condensed lower molecular weight fragments of the perfluoropolyether.
Claim 17
Independent Claim
144 words
A method of breaking down perfluoropolyethers into lower molecular weight polymers, comprising the steps of: (a) providing a distillation apparatus comprising: (i) a sample vessel located in a heating zone; (ii) a condensing zone; (iii) a collection vessel connected by passageway to the condensing zone; and (iv) means for introduction of a gas; (b) placing a perfluoropolyether in the sample vessel wherein the perfluoropolyether is selected from the group consisting of perfluoropoly(ethylene oxide), perfluoropolypropylene oxide, perfluoroethylene oxide/methylene oxide/ copolymers, perfluoroethylene oxide/propylene oxide copolymers, perfluoropoly(tetramethylene oxide) and perfluoropoly(cyclohexyl oxide); (c) establishing a flow of inert gas into the apparatus; (d) heating the perfluoropolyether by raising the temperature of the heating zone from about 500° C.-600° C.; (e) maintaining the temperature in the heating zone to vaporize the lower molecular weight fragment of the perfluoropolyether; and (f) collecting condensed lower molecular weight fragments of the perfluoropolyether.
Claim 18
Independent Claim
83 words
A method of cleaving perfluoropolyether solids to produce perfluoropolyether oils, comprising the steps of: (a) providing a solid perfluoropolyether selected from the group consisting of perfluoropoly(ethylene oxide), perfluoropolypropylene oxide, perfluoroethylene oxide/methylene oxide/copolymers, perfluoroethylene oxide/propylene oxide copolymers, perfluoropoly(tetramethylene oxide) and perfluoropoly(cyclohexyl oxide); (b) heating the solid perfluoropolyether to a temperature from about 500° C.-600° C. for a period of time sufficient to cleave the perfluoropolyether into lower molecular weight fragments; and (c) condensing and collecting vaporized lower molecular weight fragments to obtain an oil.
Claim 19
Independent Claim
83 words
A method of cleaving perfluoropolyether solids to produce perfluoropolyether oils, comprising the steps of: (a) providing a solid perfluoropolyether selected from the group consisting of perfluoropoly(ethylene oxide), perfluoropolypropylene oxide, perfluoroethylene oxide/methylene oxide/copolymers, perfluoroethylene oxide/propylene oxide copolymers, perfluoropoly(tetramethylene oxide) and perfluoropoly(cyclohexyl oxide); (b) heating the solid perfluoropolyether to a temperature from about 500° C.-600° C. for a period of time sufficient to cleave the perfluoropolyether into lower molecular weight fragments; and (c) condensing and collecting vaporized lower molecular weight fragments to obtain an oil.
Claim 20
Dependent Claim
31 words
A method of claim 9, further comprising the step of: g. treating the collected perfluoropolyethers with fluorine gas to eliminate acyl fluoride end groups and any unsaturation of the collected perfluoropolyethers.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-01-15 | 1993-07-17 | 1994-01-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-01-15 | 1997-07-17 | 1998-01-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-01-15 | 2001-07-17 | 2002-01-16 | $7700.00 | Window Closed / Lapsed |