US006783691B1
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`(10) Patent N0.:
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`(45) Date of Patent:
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`US 6,783,691 B1
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`Aug. 31, 2004
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`5,616,276 A
`5,688,432 A
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`............... .. 252/67
`4/1997 Bivens et al.
`11/1997 Pearson ..................... .. 252/67
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`FOREIGN PATENT DOCUMENTS
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`42 26 431 A1
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`0 659 862 A
`94220430
`97025480
`9—208940
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`W0 95/03473
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`WO 97/15637
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`DE
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`JP
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`* cited by examiner
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`Primary Examiner—John R. Hardee
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`(74) Attorney, Agent, or Firm—Mark A. Edwards; Chyrrea
`J. Sebree
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`(57)
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`ABSTRACT
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`The present invention relates to azeotrope-like compression
`refrigerant compositions consisting essentially of difluo-
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`romethane (HFC‘32)> Pe“‘afl“°r°°‘ha“e (HFC'125)> 1>1>1>
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`2-tetrafluoroethane (HFC-134a) and 0.5-5 Weight percent of
`a hydrocarbon selected from the group consisting of:
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`mbutane; isobutane; mbutane and 2_methy1butane; mbutane
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`and n-pentane; isobutane and 2-methylbutane; and isobutane
`and n-pentane.
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`6 Claims, N0 Drawings
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`(12) United States Patent
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`Bivens et al.
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`(54) COMPOSITIONS OF DIFLUOROMETHANE,
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`PENTAFLUOROETHANE, 1,1,1,2-
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`TETRAFLUOROETHANE AND
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`HYDROCARBONS
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`(75)
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`Inventors: Donald Bernard Bivens, Kennett
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`Square, PA (US); Barbara Haviland
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`Minor, Elkton, MD (Us); Akimichi
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`Yokozeki, Wilmington, DE (US)
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`(73) Assignee: E.I. du Pont de Nemours and
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`C0mpany,Wi1mingt0n’ DE (US)
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`( * ) Notice:
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`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
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`U.S.C. 154(b) by 0 days.
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`(21) Appl. No‘: 09/523,964
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`(22)
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`Filed:
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`Mar. 20, 2000
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`(60)
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`Related U.S. Application Data
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`Provisional application No. 60/125,510, filed on Mar. 22,
`1999.
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`Int. Cl.7 ................................................ .. C09K 5/04
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`(52) U S C]
`252/67
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`(58) Field of Search .................................... .. 252/67, 68
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`References Cited
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`U.S. PATENT DOCUMENTS
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`2/1993 Shiflett
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`5,185,094 A
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`Page 1 of 8
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`Arkema Exhibit 1019
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`Arkema Exhibit 1019
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`Page 1 of 8
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`US 6,783,691 B1
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`1
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`COMPOSITIONS or DIFLUOROMETHANE,
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`PENTAFLUOROETHANE, 1,1,1,2-
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`TETRAFLUOROETHANE AND
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`HYDROCARBONS
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`CROSS REFERENCE TO RELATED
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`APPLICATIONS
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`This application claims the priority benefit of U.S. pro-
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`visional application No. 60/125,510, filed Mar. 22, 1999.
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`FIELD OF THE INVENTION
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`The present invention relates to azeotrope-like composi-
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`tions consisting essentially of difluoromethane,
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`pentafluoroethane, 1,1,1,2-tetrafluoroethane and a hydrocar-
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`bon selected from the group consisting of: n-butane; isobu-
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`tane; n-butane and 2-methylbutane; n-butane and n-pentane;
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`isobutane and 2-methylbutane; and isobutane and n-pentane.
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`BACKGROUND
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`In recent years it has been pointed out that certain kinds
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`of fluorinated hydrocarbon refrigerants released into the
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`atmosphere may adversely affect
`the stratospheric ozone
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`layer. Although this proposition has not yet been completely
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`established, there is a movement toward control of the use
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`and the production of certain chlorofluorocarbons (CFCs)
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`and hydrochlorofluorocarbons (HCFCs) under an interna-
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`tional agreement. Accordingly, there is a demand for the
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`development of refrigerants that have a lower ozone deple-
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`tion potential
`than conventional CFC and HCFC-based
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`refrigerants while still achieving acceptable performance in
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`refrigeration applications. Hydrofluorocarbons (HFCs) are
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`gaining acceptance as replacements for CFCs and HCFCs as
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`HFCs contain no chlorine and, therefore, have zero ozone
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`depletion potential.
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`Mineral oils and alkylbenzenes have been conventionally
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`used as lubricants in CFC-based refrigeration systems.
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`However, the lack of solubility of these lubricants in HFC-
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`based refrigerants has precluded their use and necessitated
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`development and use of alternative lubricants for HFC-
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`based refrigeration systems, which utilize polyalkylene gly-
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`cols (PAGs) and polyol esters (POEs). A lubricant change
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`from mineral oil or alkyl benzene to POE or PAG lubricants
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`(which increases expenses in the refrigeration indusrty) is
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`required when the HFC mixtures are used to replace CFC-
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`based refrigerants. While the PAGs and POEs are suitable
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`lubricants for HFC-based refrigeration systems,
`they are
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`extremely hygroscopic and can absorb several thousand ppm
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`(parts per million) of water upon exposure to moist air. This
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`absorbed moisture leads to problems in the refrigeration
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`system, such as formation of acids which causes corrosion
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`of the refrigeration system, and the formation of intractable
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`sludges. Conversely, mineral oils and alkylbenzenes are
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`much less hygroscopic and have low solubility, less than 100
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`ppm, for water. Additionally, PAG and POE lubricants are
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`considerably more expensive than the hydrocarbon
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`lubricants, typically on the order of three to six times more
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`expensive. Consequently, there is a need and an opportunity
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`to resolve this solubility problem so that the refrigeration
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`industry may utilize mineral oil and alkylbenzene lubricants
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`with HFC-based refrigerants.
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`In refrigeration apparatus, refrigerant may be lost during
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`operation through leaks in shaft seals, hose connections,
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`soldered joints and broken lines. In addition, the refrigerant
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`may be released to the atmosphere during maintenance
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`procedures on refrigeration equipment. If the refrigerant is
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`Page 2 of 8
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`2
`not a pure component or an azeotropic or azeotrope-like
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`composition, the refrigerant composition may change when
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`leaked or discharged to the atmosphere from the refrigera-
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`tion apparatus, which may cause the refrigerant remaining in
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`the equipment to become flammable or to exhibit unaccept-
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`able refrigeration performance. Accordingly, it is desirable
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`to use as a refrigerant a single fluorinated hydrocarbon or an
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`azeotropic or azeotrope-like composition which fractionates
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`to a negilgible degree upon leak from a refrigeration appa-
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`ratus.
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`In refrigeration applications where the potential of fire or
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`fire’s toxic byproducts are a concern,
`it
`is desirable for
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`refrigerant compositions to be nonflammable in both liquid
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`and vapor phases, when charging fresh refrigerant
`to a
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`system or after refrigerant has leaked from a system.
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`Accordingly, there is a need in the refrigeration industry
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`for compositions that are non-ozone depleting,
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`nonflammable, and essentially non-fractionating azeotrope-
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`like compositions. Additionally,
`there is a need in the
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`refrigeration industry for compositions that offer improved
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`return of conventional-refrigeration lubricating oils from
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`non-compressor to compressor zones in compression-
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`refrigeration apparatus, as well as superior refrigeration
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`performance.
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`SUMMARY
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`The compositions of the present invention satsify the
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`aforementioned needs confronting the refrigeration industry.
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`The present compositions are useful as refrigerants, and in
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`particular as HCFC-22 alternatives. Unlike compositions
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`containing propane and pentane, compositions of the present
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`invention are non-flammable in both liquid and vapor
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`phases—as intially formulated and during leakage. The
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`present invention is directed to azeotrope-like compositions
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`consisting essentially of from about 1 to about 19 weight
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`percent difluoromethane (HFC-32), from about 25 to about
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`60 weight percent pentafiuoroethane (HFC-125), from about
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`24 to about 60 weight percent 1,1,1,2-tetrafluoroethane
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`(HFC-134a) and from about 0.5 to about 5 weight percent of
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`a hydrocarbon, wherein said hydrocarbon is selected from
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`the group consisting of: n-butane; isobutane; n-butane and
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`2-methylbutane; n-butane and n-pentane;
`isobutane and
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`2-methylbutane; and isobutane and n-pentane.
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`DETAILED DESCRIPTION
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`The azeotrope-like compositions of the present invention
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`consist essentially of difluoromethane (HFC-32, CHZF2,
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`normal boiling point of —51.7° C.), pentafiuoroethane (HFC-
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`125, CF3CHF2, normal boiling point of —48.5° C.), 1,1,1,
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`2-tetrafluoroethane (HFC-134a, CF3CHF2, normal boiling
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`point of —26.1° C.) and a hydrocarbon selected from the
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`group consisting of: n-butane (CH3CH2CH2CH3, normal
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`boiling point of —0.5° C.), isobutane (CH(CH3)3, normal
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`boiling point of —11.8° C.), n-butane and 2-methylbutane
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`(CH3CH2CH(CH3)2, normal boiling point of 27.9° C.),
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`n-butane and n-pentane (CH3CH2CH2CH2CH3, normal
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`boiling point of 359° C.), isobutane and 2-methylbutane;
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`and isobutane and n-pentane.
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`The azeotrope-like compositions of the present invention
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`consist essentially of from about 1 to about 19 weight
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`percent difluoromethane, from about 25 to about 60 weight
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`percent pentafluoroethane, from about 24 to about 60 weight
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`percent 1,1,1,2-tetrafluoroethane and from about 0.5 to
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`about 5 weight percent of a hydrocarbon, said hydrocarbon
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`selected from the group consisting of: n-butane; isobutane;
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`n-butane and 2-methylbutane; n-butane and n-pentane;
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`10
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`15
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`25
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`35
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`Page 2 of 8
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`US 6,783,691 B1
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`4
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`vapor and liquid phases before and after the compositions
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`leak from a container. Based on standard flammability test
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`method ASTM 681 at 100° C., the following flammability
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`limits have been determined:
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`Composition
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`HFC-125/HFC-32
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`HFC-134a/HFC-32
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`HFC-125/n-butane
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`HFC—134a/n-butane
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`Flammability Limit (Wt %)
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`57% HFC-32
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`33% HFC-32
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`6% n-butane
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`3% n-butane
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`The data show compositions with a higher amount of
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`HFC-125 can tolerate more hydrocarbon and still be non-
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`flammable. Also, HFC-32 is about 10 times less flammable
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`than hydrocarbons. To give an indication of mixture
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`flammability, the following formula gives an approximation
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`in
`of the “total equivalent hydrocarbon” (THE) present
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`mixtures that contain both HFC-32 and hydrocarbons:
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`TEH=HC+R32/10, where TEH=Total Equivalent Hydrocar-
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`bon in weight percent, HC=weight percent hydrocarbon in a
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`mixture, and R32=weight percent HFC-32 in a mixture. For
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`the compositions of the present invention,
`it is useful to
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`relate the amount of HFC-125 in the mixture to flammability
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`because HFC-125 has some degree of flame suppression.
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`Table 1 indicates the flammability limit of a mixture con-
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`taining both HFC-32 and hydrocarbons based on HFC-125
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`composition and TEH.
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`TABLE 1
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`Maximum Weight Percent
`TEH To Be Nonflammable
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`3.0
`3.3
`3.7
`4.0
`4.3
`4.7
`5.0
`5.5
`6.0
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`Weight Percent HFC-125 in
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`HFC—32/HFC-125/HFC-
`134a/HC Mixture
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`10
`20
`30
`40
`50
`60
`70
`80
`90
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`Additives known in the refrigerants field such as
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`lubricants, corrosion inhibitors, surfactants, stabilizers, anti-
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`foam agents, dyes and other appropriate materials may be
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`added to, and used in the presence of, the present compo-
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`sitions of the invention for a variety of purposes, provide
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`that such additives do not have an adverse influence on the
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`present compositions for
`their
`intended application or
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`change the basic and novel characteristics of the present
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`invention as claimed.
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`Although the present specification is directed to use of the
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`present azeotrope-like compositions as compression
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`refrigerants, the present compositions may also find utility
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`as cleaning agents, expansion agents for polyolefins and
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`polyurethanes (polymer foam blowing agents), aerosol
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`propellants, heat transfer media, gaseous dielectrics, power
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`cycle working fluids, polymerization media, particulate
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`removal fluids, carrier fluids, buffing abrasive agents and
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`displacement drying agents.
`
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`
`EXAMPLES
`
`
`Specific examples illustrating the present invention are
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`given below. Unless otherwise stated therein, all percentages
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`are by weight.
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`10
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`15
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`20
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`25
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`30
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`35
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`40
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`45
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`50
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`55
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`60
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`65
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`3
`isobutane and 2-methylbutane; and isobutane and n-pentane.
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`The preferred azeotrope-like compositions of the present
`
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`
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`invention consist essentially of from about 1 to about 15
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`weight percent difluoromethane, from about 30 to about 50
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`weight percent pentafluoroethane, from about 30 to about 50
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`weight percent 1,1,1,2-tetrafluoroethane and from about 1 to
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`about 4 weight percent of the aforementioned hydrocarbons.
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`The most preferred azeotrope-like compositions of the
`
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`
`
`present invention consist essentially of 1-9 weight percent
`
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`
`
`difluoromethane (HFC-32), 30-50 weight percent pen-
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`tafluoroethane (HFC-125), 30-50 weight percent 1,1,1,2-
`
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`
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`tetrafluoroethane (HFC-134a) and 1-4 weight percent of the
`
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`
`
`aforementioned hydrocarbons.
`
`
`As previously stated, in refrigeration apparatus, refriger-
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`ant may be lost during operation through leaks in shaft seals,
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`hose connections, soldered joints and broken lines.
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`Additionally, the refrigerant may be released to the atmo-
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`sphere during maintenance procedures on refrigeration
`
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`
`
`equipment. If the refrigerant is not a pure component or an
`
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`
`
`azeotropic or azeotrope-like composition,
`the refrigerant
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`composition may change when leaked or discharged to the
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`atmosphere from the refrigeration apparatus, which may
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`cause the refrigerant remaining in the equipment to become
`
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`flammable or to exhibit unacceptable refrigeration perfor-
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`mance. Accordingly, it is desirable to use as a refrigerant a
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`
`
`single fluorinated hydrocarbon or an azeotropic or
`
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`
`
`azeotrope-like composition, such as the present invention,
`
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`
`
`
`which fractionates to a negilgible degree upon leak from a
`
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`
`
`refrigeration apparatus.
`
`
`By azeotrope-like composition is meant a constant
`
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`
`
`boiling, or substantially constant boiling, liquid admixture
`
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`
`
`of two or more substances that behaves as a single sub-
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`stance. One way to characterize an azeotrope-like compo-
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`sition is that the vapor produced by partial evaporation or
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`distillation of the liquid has substantially the same compo-
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`sition as the liquid from which it was evaporated or distilled,
`
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`that is,
`the admixture distills/refluxes without substantial
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`composition change. Another way to characterize an
`
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`
`azeotrope-like composition is that the bubble point vapor
`
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`
`pressure and the dew point vapor pressure of the composi-
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`tion at a particular temperature are substantially the same.
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`Herein, a composition is azeotrope-like if, after 50 weight
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`percent of the composition is removed, such as by evapo-
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`ration or boiling off,
`the difference in vapor pressure
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`
`between the original composition and the composition
`
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`remaining after 50 weight percent of the original composi-
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`tion has been removed is less than about 10 percent.
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`By effective amount is meant the amount of each com-
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`
`
`ponent of the inventive compositions which, when
`
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`
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`
`
`
`combined, results in the formation of an azeotrope-like
`
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`
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`composition. This definition includes the amounts of each
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`
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`component, which amounts may vary depending on the
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`pressure applied to the composition so long as the azeotrope-
`
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`
`like compositions continue to exist at the different pressures,
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`but with possible different boiling points. Therefore, effec-
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`tive amount includes the amounts, such as may be expressed
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`in weight percentages, of each component of the composi-
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`
`
`tions of the instant invention, which form an azeotrope-like
`
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`
`
`
`composition at
`temperatures or pressures other than as
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`
`
`
`described herein.
`
`
`The azeotrope-like compositions of the present invention
`
`
`
`
`
`
`can be prepared by any convenient method including mixing
`
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`
`
`or combining effective amounts of components. Apreferred
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`
`
`method is to weigh the desired component amounts, and
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`thereafter, combine them in an appropriate container.
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`Asurprising result, and an important feature of the present
`
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`
`
`compositions, is that they remain nonflammable in both the
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`Page 3 of 8
`
`Page 3 of 8
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`

`
`
`
`US 6,783,691 B1
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`
`
`6
`Example 2
`
`
`Impact of Vapor Leakage on Compositional Change
`
`
`
`
`
`
`at 25° C. of a HFC—32, HFC—125, HFC-134a,
`
`
`
`
`
`
`
`Isobutane and Optionally 2-methylbutane or n-
`
`
`
`
`
`pentane Composition
`
`
`A vessel is charged to 90 volume % full with an initial
`
`
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`
`
`
`
`
`composition of HFC—32, HFC—125, HFC-134a, isobutane
`
`
`
`
`
`
`and optionally 2-methylbutane or n-pentane at 25° C. The
`
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`
`
`
`
`
`
`initial liquid and vapor compositions are measured by gas
`
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`
`
`chromatography. The composition is allowed to leak from
`
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`the vessel, while the temperature is held constant at 25° C.,
`
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`
`until 50 weight percent of the initial composition is
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`removed, at which time the liquid and vapor compositions
`
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`
`
`
`
`remaining in the vessel are again measured. The vessel is
`
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`
`
`than allowed to continue to leak until all the liquid is gone.
`
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`
`In all cases,
`liquid was gone after about 97 wt % was
`
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`
`
`
`removed. The results are summarized in Table 3 below. All
`
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`
`compositions are given in weight %.
`
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`
`
`TABLE 3
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`
`10
`
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`
`15
`
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`
`20
`
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`
`25
`
`
`
`30
`
`
`
`35
`
`
`
`40
`
`
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`
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`
`
`TABLE 2
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`
`5
`Example 1
`
`
`Impact of Vapor Leakage on Compositional Change
`
`
`
`
`
`
`at 25° C. of a HFC—32, HFC—125, HFC-134a, n-
`
`
`
`
`
`
`
`butane and Optionally 2-methylbutane or n-pentane
`
`
`
`
`
`Composition
`
`A vessel is charged to 90 volume % full with an initial
`
`
`
`
`
`
`
`
`
`
`
`composition of HFC—32, HFC—125, HFC-134a, n-butane and
`
`
`
`
`
`optionally 2-methylbutane or n-pentane at 25° C. The initial
`
`
`
`
`
`
`
`
`liquid and vapor compositions are measured by gas chro-
`
`
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`
`
`
`
`
`matography. The composition is allowed to leak from the
`
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`
`vessel, while the temperature is held constant at 25° C., until
`
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`50 weight percent of the initial composition is removed, at
`
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`
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`which time the liquid and vapor compositions remaining in
`
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`
`the vessel are again measured. The vessel is than allowed to
`
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`continue to leak until all the liquid is gone. In all cases,
`
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`
`liquid was gone after about 97 wt % was removed. The
`
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`
`
`results are summarized in Table 2 below. All compositions
`
`
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`
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`
`
`
`are given in weight %.
`
`
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`
`
`97%
`Leak-
`
`Vapor
`1.9
`18.1
`79.3
`0.7
`0.9
`2.2
`19.8
`77.2
`0.8
`1.0
`2.0
`17.0
`78.9
`0.6
`1.5
`2.3
`1.6
`5.0
`92.4
`0.0
`1.0
`1.2
`6.5
`29.2
`62.7
`0.2
`1.4
`2.2
`
`
`
`
`
`97%
`I_.eak-
`
`Liquid
`1.0
`10.7
`88.0
`0.3
`0.4
`1.1
`11.8
`86.7
`0.4
`0.5
`1.0
`10.0
`86.4
`0.4
`2.2
`2.7
`0.8
`2.7
`95.4
`0.0
`1.1
`1.2
`3.7
`19.0
`74.9
`0.1
`2.3
`2.8
`
`
`
`
`
`50%
`I_.eak-
`
`Vapor
`9.8
`49.9
`37.5
`2.8
`3.8
`10.9
`50.8
`35.5
`2.8
`3.9
`10.9
`48.9
`37.6
`2.2
`0.4
`3.7
`16.5
`26.6
`55.9
`0.6
`0.4
`2.6
`20.7
`53.2
`25.3
`0.5
`0.3
`2.9
`
`
`
`
`
`
`
`50%
`I_.eak-
`
`Liquid
`6.5
`39.0
`52.4
`2.
`2.7
`7.4
`40.2
`50.3
`2.
`2.8
`7.2
`38.0
`52.4
`1.7
`0.7
`3.
`9.9
`18.
`71.
`0.3
`0.6
`1.9
`15.
`45.3
`38.5
`0.4
`0.7
`2.6
`
`
`
`
`
`
`
`Initial
`Vapor
`12.7
`55.3
`29.0
`3.0
`4.3
`14.0
`55.7
`27.3
`3.0
`4.4
`14.2
`54.2
`29.0
`2.4
`0.2
`4.0
`23.0
`32.3
`43.6
`0.8
`0.3
`3.4
`24.6
`55.8
`18.8
`0.6
`0.2
`3.3
`
`
`
`
`
`
`
`Initial
`
`Liquid
`
`0.0
`4 5.0
`4 2.5
`2.5
`3.5
`0.0
`4 7.0
`4 0.5
`2.5
`3.5
`0.0
`4 5.5
`4 2.5
`2.0
`0.5
`3.5
`5.0
`24.0
`60.0
`0.5
`0.5
`2.5
`19
`50
`30
`0.5
`0.5
`2.9
`
`
`
`
`
`
`
`HFC—32
`
`HFC—125
`
`HFC-134a
`Isobutane
`The
`HFC—32
`
`
`HFC—125
`
`HFC-134a
`Isobutane
`The
`HFC—32
`
`
`HFC—125
`
`HFC-134a
`Isobutane
`n-pentane
`The
`
`HFC—32
`
`HFC—125
`
`HFC-134a
`Isobutane
`2-mbutane
`
`The
`HFC—32
`
`
`HFC—125
`
`HFC-134a
`Isobutane
`n-pentane
`THE
`
`
`
`
`
`
`
`
`When TEH values of this Example are compared to Table
`
`
`
`
`
`
`
`
`
`
`1, results show compositions are essentially nonflammable,
`
`
`
`
`
`
`
`initially and as contents are completely leaked out of the
`
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`
`
`
`container. Data also show addition of a higher boiling
`
`
`
`
`
`
`
`
`
`hydrocarbon such as n-pentane reduces initial vapor phase
`
`
`
`
`
`
`
`
`flammability when compared to using only isobutane.
`
`
`
`
`
`
`
`Example 3
`
`
`Impact of Vapor Leakage on Vapor Pressure at 25°
`
`
`
`
`
`
`
`
`C.
`
`A vessel is charged with an initial composition at 25° C.,
`
`
`
`
`
`
`
`
`
`
`and the initial vapor pressure of the composition is mea-
`
`
`
`
`
`
`
`
`
`sured. The composition is allowed to leak from the vessel
`
`
`
`
`
`
`
`
`
`while the temperature is held constant at 25° C. until 50
`
`
`
`
`
`
`
`
`
`
`weight percent of the initial composition is removed, at
`
`
`
`
`
`
`
`
`which time the vapor pressure of the composition remaining
`
`
`
`
`
`
`
`
`in the vessel is measured. The results are summarized in
`
`
`
`
`
`
`
`
`
`Table 4 below.
`
`
`
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`
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`
`
`
`
`
`
`
`
`
`45
`
`
`
`50
`
`
`
`55
`
`
`60
`
`
`
`65
`
`
`
`97%
`Leak-
`
`Vapor
`1.9
`18.1
`78.4
`1.6
`1.8
`2.1
`17.6
`78.7
`1.6
`1.8
`1.9
`17.7
`80.3
`0.1
`0.3
`1.4
`14.1
`78.5
`6.0
`6.1*
`2.0
`17.1
`
`78.2
`1.4
`1.3
`2.9
`0.5
`6.8
`90.0
`0.8
`1.9
`2.8
`1.0
`18.8
`77.5
`1.2
`1.5
`2.8
`
`
`
`
`
`
`
`
`
`
`
`
`
`97%
`Leak-
`
`Liquid
`1.0
`10.7
`87.3
`1.0
`1.1
`1.1
`10.4
`87.5
`1.0
`1.1
`1.0
`10.3
`88.7
`0.0
`0.1
`0.7
`7.6
`72.7
`19.0
`19.1*
`1.0
`10.1
`86.1
`0.9
`1.9
`2.9
`0.2
`3.7
`93.1
`0.5
`2.5
`3.0
`0.5
`11.2
`85.1
`0.9
`
`2.3
`3.2
`
`
`
`
`
`
`
`
`
`
`
`
`
`50%
`Leak-
`
`Vapor
`9.9
`49.9
`37.6
`2.6
`3.6
`0.9
`48.8
`37.6
`2.7
`3.8
`1.0
`49.2
`37.3
`2.5
`3.6
`1.0
`49.1
`38.2
`1.7
`2.8
`0.9
`48.9
`37.7
`2.1
`0.4
`3.6
`5.4
`35.5
`56.3
`2.2
`0.6
`3.3
`5.5
`54.3
`38.0
`1.9
`0.3
`2.9
`
`
`
`
`
`
`
`
`
`50%
`Lea.k-
`
`Liquid
`6.5
`38.8
`52.3
`2.4
`3.0
`7.3
`37.9
`52.4
`2.4
`3.1
`7.3
`38.8
`52.9
`.0
`.7
`7.1
`37.3
`
`5 .9
`3.6
`4.3*
`7.3
`37.8
`52.3
`.9
`0.7
`3.3
`3.2
`24 .1
`69.9
`.7
`.1
`3.1
`3.6
`4 .8
`52.2
`.7
`0.7
`2.8
`
`
`
`
`
`
`
`
`
`
`
`Initial
`Vapor
`12.8
`55.6
`29.1
`2.5
`3.8
`14.2
`54.3
`29.0
`2.5
`3.9
`13.9
`52.3
`28.3
`5.5
`6.9*
`
`14.4
`55.1
`29.3
`1.2
`2.6
`14.2
`54.5
`29.0
`2.0
`0.3
`3.7
`8.0
`43.9
`45.4
`2.3
`0.4
`3.5
`7.2
`61.0
`29.7
`1.9
`0.2
`2.9
`
`
`
`
`
`
`
`
`
`HFC—32
`
`HFC— 25
`
`HFC— 34a
`n-butane
`The
`HFC—32
`
`
`HFC— 25
`
`HFC— 34a
`n-butane
`The
`HFC—32
`
`
`HFC— 25
`
`HFC— 34a
`Propane
`The
`HFC—32
`
`
`HFC— 25
`
`HFC— 34a
`n-pentane
`The
`HFC—32
`
`
`HFC— 25
`
`HFC— 34a
`
`n-butane
`
`2-mbutane
`The
`HFC—32
`
`
`HFC—125
`
`HFC—134a
`
`n-butane
`
`2-mbutane
`The
`HFC—32
`
`
`HFC—125
`
`HFC—134a
`n-butane
`
`n-pentane
`THE
`
`*Compositions are flammable based on TEH analysis
`
`
`
`
`
`
`
`Initial
`
`Liquid
`
`9.0
`46.0
`42.5
`2.5
`3.4
`0.0
`45.0
`42.5
`2.5
`3.5
`0.0
`45.0
`42.5
`2.5
`3.5
`0.0
`45.0
`4 2.5
`2.5
`3.5
`0
`45
`42.5
`2.0
`0.5
`3.5
`5.0
`32.2
`60.0
`2.0
`0.8
`2.9
`5
`
`50
`
`42.7
`1.8
`0.5
`2.8
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`When TEH values of this Example are compared to Table
`
`
`
`
`
`
`
`
`
`
`1, results show compositions of the precent invention are
`
`
`
`
`
`
`
`
`
`essentially nonflammable, initially and as contents are com-
`
`
`
`
`
`
`
`pletely leaked out of the container. Data also show addition
`
`
`
`
`
`
`
`
`
`
`of a higher boiling hydrocarbon such as 2-methylbutane
`
`
`
`
`
`
`
`
`reduces initial vapor phase flammability when compared to
`
`
`
`
`
`
`
`
`using only n-butane. Compositions containing propane are
`
`
`
`
`
`
`
`flammable initially in the vapor phase and compositions
`
`
`
`
`
`
`
`
`containing n-pentane become flammable in the liquid and/or
`
`
`
`
`
`
`
`
`vapor phases as liquid is removed.
`
`
`
`
`
`
`
`Page 4 of 8
`
`Page 4 of 8
`
`

`
`
`
`US 6,783,691 B1
`
`
`
`7
`
`
`
`
`8
`Example 4
`
`
`
`
`
`
`10
`
`
`
`15
`
`
`
`20
`
`
`
`25
`
`
`
`Effect of Hydrocarbon Addition on Fractionation
`
`
`
`
`
`
`
`
`A vessel is charged 90% full by volume with an initial
`
`
`
`
`
`
`
`
`
`
`
`composition at 25° C., and the initial vapor pressure of the
`
`
`
`
`
`
`
`
`
`
`
`composition is measured. The composition is allowed to
`
`
`
`
`
`
`
`
`leak from the vessel, while the temperature is held constant
`
`
`
`
`
`
`
`
`
`
`at 25° C. until 50 weight percent of the initial composition
`
`
`
`
`
`
`
`
`
`
`
`is removed, at which time the vapor pressure of the com-
`
`
`
`
`
`
`
`
`
`
`position remaining in the vessel is measured. The results are
`
`
`
`
`
`
`
`
`
`summarized in Table 5 below.
`
`
`
`
`
`
`
`
`
`
`TABLE 5
`
`Initial
`
`Pressure
`(Pa)
`
`179
`
`
`
`
`
`Pressure
`
`After
`
`Lea< (kPa)
`
`055
`
`
`
`
`
`
`
`% Change in
`
`
`Pressure
`
`10.5
`
`
`
`241
`
`193
`
`142
`
`083
`
`
`
`
`
`
`
`
`
`135
`
`093
`
`051
`
`005
`
`
`
`
`
`
`
`
`
`8.5
`
`8.4
`
`8.0
`
`7.2
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`TABLE 4
`
`
`
`Initial
`Pressure
`
`(
`(Pa)
`
`
`
`Pressure
`After Leak
`
`
`({Pa)
`
`
`
`
`
`
`
`% Change
`
`in
`Pressure
`
`
`
`
`
`
`Composition (Wt %)
`
`
`
`HFC-32/HFC- 125/HFC- 134/n-butane
`
`
`
`5.4
`5.6
`7.9
`9.0
`5.5
`9.7
`8.0
`
`
`
`5.2
`5.6
`8.0
`9.1
`9.5
`9.6
`8.1
`7.6
`
`
`
`042
`272
`044
`891
`245
`038
`051
`
`
`
`065
`275
`055
`895
`261
`059
`062
`078
`
`
`
`
`
`
`
`.0/60.0/34.0/5.0
`
`9.0/56.5/24.0/0.5
`
`9.0/46.0/42.5/2.5
`5.0/34.0/60.0/1.0
`6.0/57.0/24.0/3.0
`9.0/25.0/51.0/5.0
`0.0/45.0/42.5/2.5
`HFC—32/HFC—125/HFC-
`34a/isobutane
`
`
`
`
`
`
`
`
`.0/60.0/34.0/5.0
`
`9.0/56.5/24.0/0.5
`
`9.0/46.0/42.5/2.5
`5.0/34.0/60.0/1.0
`6.0/57.0/24.0/3.0
`9.0/25.0/51.0/5.0
`0.0/45.0/42.5/2.5
`0.0/47.0/40.5/2.5
`
`
`HFC—32/HFC-125/HFC—134a/n-
`butane/2-methylbutane
`
`
`
`
`
`
`
`
`
`
`
`
`
`Composition (Wt %)
`
`
`
`HFC-32/HFC- 25/HFC-134a
`(refrigerant “R407C”)
`
`
`(23/25/52)
`
`HFC-32/HFC- 25/HFC-134a
`(20/40/40)
`
`HFC-32/HFC- 25/HFC-
`134a/n-butane(15/42/41.5/1.5)
`HFC-32/HFC- 25/HFC-
`134a/n-butane(10/45/42.5/2.5)
`
`
`HFC-32/HFC- 25/HFC-
`134a/n-butane(5/48/44/3)
`
`HFC-32/HFC- 25/HFC-
`134a/isobutane(15/42/41.5/1.5)
`HFC-32/HFC- 25/HFC-
`134a/isobutane(10/45/42.5/2.5)
`
`
`
`
`HFC-32/HFC- 25/HFC-
`134a/isobutane(5/48/44/3)
`
`
`
`
`
`
`
`200
`
`155
`
`098
`
`
`
`
`
`
`
`099
`
`062
`
`017
`
`
`
`
`
`
`
`8.4
`
`
`
`8.1
`
`
`7.4
`
`
`
`The results of this Example show that fractionation is
`
`
`
`
`
`
`
`
`reduced; compositions become more azeotrope-like as HFC-
`
`
`
`
`
`
`32 is replaced with the present hydrocarbons. Compositions
`
`
`
`
`
`
`
`
`of the present invention also have less fractionation than
`
`
`
`
`
`
`
`
`
`refrigerant composition R407C.
`
`
`
`
`
`
`Example 5
`
`
`
`
`Refrigerant Performance
`
`
`
`
`The following table shows the performance of composi-
`
`
`
`
`
`
`
`tions of the present invention. The data are based on the
`
`
`
`
`
`
`
`
`
`
`following conditions.
`
`
`
`
`
`Evaporator temperature 8.9° C.
`
`
`
`
`Condenser temperature 46.1° C.
`
`
`
`
`Subcool temperature 39.4° C.
`
`
`
`
`Return gas temperature 18.3° C.
`
`
`
`
`
`Compressor clearance volume is 4%
`
`
`
`
`
`Compressor isentropic efficiency is 75%
`
`
`
`
`
`Capacity is intended to mean the change in enthalpy of the
`
`
`
`
`
`
`
`
`
`
`
`refrigerant
`in the evaporator per pound of refrigerant
`
`
`
`
`
`
`
`
`circulated, i.e. the heat removed by the refrigerant in the
`
`
`
`
`
`
`
`
`
`
`evaporator per time. Coefficient of Performance (COP) is
`
`
`
`
`
`
`
`
`intended to mean the ratio of the capacity to compressor
`
`
`
`
`
`
`
`
`
`
`work, It is a measure of refrigerant energy efficiency. Results
`
`
`
`
`
`
`
`
`are shown in Table 6 below.
`
`
`
`
`
`
`
`30
`
`
`
`35
`
`
`
`40
`
`
`
`45
`
`
`
`50
`
`
`
`55
`
`
`60
`
`
`65
`
`
`7.4
`5.8
`8.6
`9.1
`6.0
`10.0
`8.3
`
`
`
`7.8
`5.9
`8.8
`9.0
`6.1
`10.0
`8.3
`
`
`
`7.4
`5.8
`8.6
`9.1
`5.9
`10.0
`8.2
`
`
`
`7.8
`5.9
`8.7
`9.1
`6.1
`10.0
`8.4
`12.1
`
`
`
`985
`264
`024
`885
`231
`031
`044
`
`
`
`
`
`
`
`975
`1262
`1020
`885
`1229
`1030
`1043
`
`987
`267
`028
`887
`242
`050
`053
`
`977
`265
`024
`886
`238
`049
`051
`096
`
`
`
`
`
`064
`342
`120
`974
`310
`145
`138
`
`058
`341
`118
`973
`309
`145
`137
`
`
`
`066
`345
`125
`976
`320
`167
`147
`
`
`
`060
`344
`122
`975
`319
`166
`147
`247
`
`
`
`
`
`.0/60.0/34.0/0.5/4.5
`
`9.0/56.5/24.0/0.5/0.5
`
`9.0/46.0/42.5/1.0/1.5
`5.0/34.0/60.0/0.5/0.5
`6.0/57.0/24.0/2.0/1.0
`9.0/25.0/51.0/4.5/0.5
`
`
`0.0/45.0/42.5/2.0/0.5
`HFC—32/HFC-125/HFC—134a/n-
`butane/n-pentane
`
`
`
`
`
`
`.0/60.0/34.0/0.5/4.5
`
`9.0/56.5/24.0/0.5/0.5
`
`9.0/46.0/42.5/1.0/1.5
`5.0/34.0/60.0/0.5/0.5
`6.0/57.0/24.0/2.0/1.0
`9.0/25.0/51.0/4.5/0.5
`
`
`0.0/45.0/42.5/2.0/0.5
`HFC—32/HFC—125/HFC-
`34a/isobutane/2-methylbutane
`
`
`
`
`
`
`
`
`
`
`
`
`
`.0/60.0/34.0/0.5/4.5
`
`9.0/56.5/24.0/0.5/0.5
`
`9.0/46.0/42.5/1.0/1.5
`5.0/34.0/60.0/0.5/0.5
`6.0/57.0/24.0/2.0/1.0
`9.0/25.0/51.0/4.5/0.5
`
`
`0.0/45.0/42.5/2.0/0.5
`HFC—32/HFC—125/HFC-
`34a/isobutane/n-pentane
`
`
`
`
`
`
`
`
`
`.0/60.0/34.0/0.5/4.5
`
`9.0/56.5/24.0/0.5/0.5
`
`9.0/46.0/42.5/1.0/1.5
`5.0/34.0/60.0/0.5/0.5
`6.0/57.0/24.0/2.0/1.0
`9.0/25.0/51.0/4.5/0.5
`
`
`0.0/45.0/42.5/2.0/0.5
`HFC-32/HPC-125/HPC-134a/propane
`(10.0/45.0/42.5/2.5
`
`
`
`
`
`
`
`
`
`
`
`The results of this Example show azeotrope-like compo-
`
`
`
`
`
`
`
`sitions of the present invention are present as after 50 wt %
`
`
`
`
`
`
`
`
`
`
`
`
`of an original composition is removed, the vapor pressure of
`
`
`
`
`
`
`
`
`
`
`the remaining composition is changed by less th