Refrigeration – Processes – Employing diverse materials or particular material in...
Reexamination Certificate
1996-03-01
2004-02-10
Hardee, John (Department: 1751)
Refrigeration
Processes
Employing diverse materials or particular material in...
C252S067000, C521S098000, C521S131000, C264S053000
Reexamination Certificate
active
06688118
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to compositions containing cyclopentane. More particularly, this invention relates to azeotropic compositions containing (1) cyclopentane and a hydrofluorocarbon; (2) cyclopentane and a hydrofluoroether or (3) cyclopentane and a fluorinated sulfur compound. These compositions are useful as cleaning agents, expansion agents for polyolefins and polyurethanes, aerosol propellants, refrigerants, heat transfer media, gaseous dielectrics, fire extinguishing agents, power cycle working fluids, polymerization media, particulate removal fluids, carrier fluids, buffing abrasive agents, and displacement drying agents.
BACKGROUND OF THE INVENTION
Fluorinated hydrocarbons have many uses, one of which is as a refrigerant. Such refrigerants include dichlorodifluoromethane (CFC-12) and chlorodifluoromethane (HCFC-22).
In recent years it has been pointed out that certain kinds of fluorinated hydrocarbon refrigerants released into the atmosphere may adversely affect the stratospheric ozone layer. Although this proposition has not yet been completely established, there is a movement toward the control of the use and the production of certain chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) under an international agreement.
Accordingly, there is a demand for the development of refrigerants that have a lower ozone depletion potential than existing refrigerants while still achieving an acceptable performance in refrigeration applications. Hydrofluorocarbons (HFCs) have been suggested as replacements for CFCs and HCFCs since HFCs have no chlorine and therefore have zero ozone depletion potential.
In refrigeration applications, a refrigerant is often lost during operation through leaks in shaft seals, hose connections, soldered joints and broken lines. In addition, the refrigerant may be released to the atmosphere during maintenance procedures on refrigeration equipment. If the refrigerant is not a pure component or an azeotropic or azeotrope-like composition, the refrigerant composition may change when leaked or discharged to the atmosphere from the refrigeration equipment, which may cause the refrigerant to become flammable or to have poor refrigeration performance.
Accordingly, it is desirable to use as a refrigerant a single fluorinated hydrocarbon or an azeotropic or azeotrope-like composition that includes one or more fluorinated hydrocarbons.
Fluorinated hydrocarbon are also useful as blowing agents in the manufacture of polyurethane, phenolic and thermoplastic foams.
Fluorinated hydrocarbons may also be used as cleaning agents or solvent to clean, for example, electronic circuit boards. It is desirable that the cleaning agents be azeotropic or azeotrope-like because in vapor degreasing operations the cleaning agent is generally redistilled and reused for final rinse cleaning.
Fluorinated hydrocarbons may also be used as propellants in aerosols, as heat transfer media, gaseous dielectrics, fire extinguishing agents, power cycle working fluids such as for heat pumps, inert media for polymerization reactions, fluids for removing particulates from metal surfaces, as carrier fluids that may be used, for example, to place a fine film of lubricant on metal parts, as buffing abrasive agents to remove buffing abrasive compounds from polished surfaces such as metal, as displacement drying agents for removing water, such as from jewelry or metal parts, as resist developers in conventional circuit manufacturing techniques including chlorine-type developing agents, or as strippers for photoresists when used with, for example, a chlorohydrocarbon such as 1,1,1-trichloroethane or trichloroethylene.
SUMMARY OF THE INVENTION
The present invention relates to the discovery of compositions containing cyclopentane and tetrafluoroethane, hexafluoropropane, pentafluoropropane, tetrafluoropropane, trifluoropropane, difluoropropane, octafluorobutane, hexafluorobutane, pentafluorobutane, nonafluorobutane, difluorobutane, trifluoro-2-methoxyethane or bis(pentafluoroethyl)sulfide. Compounds useful for practicing the present invention include the following: 1,1,2,2-tetrafluoroethane (HFC-134), 1,1,2,2,3,3-hexafluoropropane (HFC-236ca), 1,1,2,2,3-pentafluoropropane (HFC-245ca), 1,1,2,3,3-pentafluoropropane (HFC-245ea), 1,1,1,2,3-pentafluoropropane (HFC-245eb), 1,1,1,3,3-pentafluoropropane (HFC-245fa), 1,2,2,3-tetrafluoropropane (HFC-254ca), 1,1,3-trifluoropropane (HFC-263fa), 1,2-difluoropropane (HFC-272ea), 1,3-difluoropropane (HFC-272fa), 1,1,1,2,2,3,3,4-octafluorobutane (HFC-338mcc), 1,1,1,2,3,4,4,4-octafluorobutane (HFC-338mee), 1,1,1,2,2,4,4,4-octafluorobutane (HFC-338mf), 1,1,1,2,2,4-hexafluorobutane (HFC-356mcf), 1,1,1,4,4,4-hexafluorobutane (HFC-356mff), 1,1,1,3,3-pentafluorobutane (HFC-365mfc), 2,3-difluorobutane (HFC-392see), 1,1,1,2,2,3,3,4,4-nonafluorobutane(HFC-329p) 1,1,1-trifluoro-2-methoxyethane (263fbE&ggr;&bgr;), or bis(pentafluoroethyl)sulfide (CF
3
CF
2
SCF
2
CH
3
). These compositions are also useful as cleaning agents, expansion agents for polyolefins and polyurethanes, aerosol propellants, heat transfer media, gaseous dielectrics, fire extinguishing agents, power cycle working fluids, polymerization media, particulate removal fluids, carrier fluids, buffing abrasive agents, and displacement drying agents.
Further, the invention relates to the discovery of binary azeotropic or azeotrope-like compositions comprising effective amounts of cyclopentane and tetrafluoroethane, hexafluoropropane, pentafluoropropane, tetrafluoropropane, trifluoropropane, difluoropropane, octafluorobutane, hexafluorobutane, pentafluorobutane, nonafluorobutane, difluorobutane, trifluoro-2-methoxyethane or bis(pentafluoroethyl)sulfide to form an azeotropic or azeotrope-like composition.
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Fukushima et al., “Working Fluid Mixtures for Refrigerators and Heat Pumps”,Chemical Abstracts—Abstract 137383, 111, No. 16, Oct. 16, 1989.
Fukushima et al., “Working Fluids for Refrigerators and Heat Pumps”,Chemical Abstracts—Abstract No. 137386, 111, No. 16, Oct. 16, 1989.
Database WPI, Class E19, AN 89-202053 and JP 01 139 678 (Asahi Glass Co. Ltd),Derwent Publications Ltd., London, GB, Section Ch, Week 8928, Jun. 1, 1989.
Database WPI, AN 89-202050 and JP 01 139 675 (Asahi Glass),Derwent Publications Ltd., London, GB, Week 8928, Jun. 1, 1989.
E. I. du Pont de Nemours and Company
Edwards Mark A.
Hardee John
Sebree Chyrrea J.
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