Patent Application
20110088418
1. Field of the Disclosure
The present disclosure relates to compositions comprising at least one ionic liquid and at least one fluoroolefin. These compositions are useful as working fluid pairs in absorption cycle systems.
The present disclosure relates to compositions comprising at least one ionic liquid and at least one fluoroolefin. These compositions are useful as working fluid pairs in absorption cycle systems.
2. Description of Related Art
New environmental regulations on working fluids have forced the refrigeration and air-conditioning industry to look for new working fluids with low global warming potential (GWP). There are numerous other applications for fluorocarbon working fluids, such as in the area of fire suppression, in preparation of foams as expansion agents, and as aerosol propellants, to mention a few.
Most currently used absorption cycle systems use water as the refrigerant and LiBr as the absorbent. The use of water requires operation at pressures substantially lower than atmospheric pressure resulting in systems of large size and high cost. The use of highly corrosive LiBr requires expensive materials of construction, imposes higher maintenance costs, reduces the useful life of the equipment and necessitates the use of environmentally harmful chromate corrosion inhibitors that prevents penetration into markets where heavy metals are banned. Moreover, precipitation of LiBr from LiBr-water solutions limits the range of feasible operating conditions thus limiting the energy efficiency of the absorption cycle and preventing use of innovations such as the use of air-cooled condensers and absorbers. Air-cooled operation eliminates the need for water cooling towers and their associated first costs, operation costs, maintenance costs, space requirements, and consumption of large quantities of water (a limited resource in some areas of the world).
Some currently used absorption cycle systems use ammonia as the refrigerant and water as the absorbent. Ammonia is toxic, flammable and corrosive. The use of volatile water as the absorbent requires a rectifier to capture water vapor escaping from the generator and provide anhydrous ammonia to the condenser. The rectifier adds to the system start-up cost and to the operating costs throughout the life of the system due to the additional required energy consumption.
Replacement working fluids are being sought for absorption cycle systems that have low GWP, no toxicity, non-flammability, reasonable cost and performance to match existing systems.
Disclosed herein is a composition comprising at least one ionic liquid and at least one fluoroolefin, wherein said composition comprises at least about 1 weight percent of said at least one fluoroolefin.
Also disclosed herein is a process for producing cooling comprising forming a refrigerant/absorbent mixture, heating said mixture to release refrigerant vapor, condensing said refrigerant to form liquid refrigerant, evaporating said liquid refrigerant in the vicinity of a heat transfer fluid, transferring said heat transfer fluid to the vicinity of a body to be cooled, and reforming the absorbent/refrigerant solution; wherein said refrigerant/absorbent mixture comprises at least one ionic liquid and at least one fluoroolefin.
Also disclosed herein is a process for transferring heat comprising moving a heat transfer fluid from a heat source to a heat sink, wherein the heat source is an absorption cycle utilizing a working fluid pair comprising at least one ionic liquid and at least one fluoroolefin.
Also disclosed herein is an absorption cycle system apparatus comprising an absorber, a generator, a condenser, an expansion device, and an evaporator, wherein the working fluids contained within said apparatus comprise at least one ionic liquid and at least one fluoroolefin.
The present invention may be better understood with reference to the following figures, wherein:
The present invention provides a composition comprising at least one ionic liquid and at least one fluoroolefin.
A heat transfer medium (also referred to herein as a heat transfer fluid, a heat transfer composition or a heat transfer fluid composition) is a working fluid used to carry heat from a heat source to a heat sink.
A refrigerant is a compound or mixture of compounds that function as a heat transfer fluid in a cycle wherein the fluid sometimes undergoes a phase change from a liquid to a gas and back. In certain instances, a refrigerant may not undergo a phase change, such as for carbon dioxide. In absorption cycle systems, a refrigerant is the volatile component of a working fluid pair.
A working fluid pair is a pair of fluids comprising an absorbent and a refrigerant used to provide the cooling or heating in an absorption cycle system. In general, the working fluids will have an affinity for one another, e.g. solubility of one in the other.
An absorbent is a working fluid that is the non-volatile component of a working fluid pair as used in an absorption cycle system.
An absorption cycle system is any system that produces heating or cooling by use of a working fluid pair and the absorption effect as described herein. In one embodiment, an absorption cycle system comprises an absorption chiller that produces cooling. In another embodiment, an absorption cycle system comprises an absorption heat pump that may produce heat or cooling. In another embodiment, an absorption cycle system comprises an absorption heater. Absorption cycle systems are used to provide cooling or heating in areas with no, or little access to electricity. Additionally, absorption cycle systems provide more efficient use of power resources.
In one embodiment, disclosed herein are compositions comprising working fluid pairs.
In one embodiment, disclosed are compositions comprising at least one ionic liquid and at least one fluoroolefin. In one embodiment, the disclosed compositions function as working fluid pairs in absorption cycle systems.
Ionic liquids are organic compounds that are liquid at temperatures below 100° C. They differ from most salts in that they have low melting points, they tend to be liquid over a wide temperature range, and have been shown to have high heat capacities. Ionic liquids have essentially no vapor pressure, and they can either be neutral, acidic or basic. The properties of an ionic liquid can be tailored by varying the cation and anion. A cation or anion of an ionic liquid useful for the present invention can, in principle, be any cation or anion such that the cation and anion together form an organic salt that is liquid at or below about 100° C.
Many ionic liquids are formed by reacting a nitrogen-containing heterocyclic ring, preferably a heteroaromatic ring, with an alkylating agent (for example, an alkyl halide) to form a quaternary nitrogen-containing salt, and performing ion exchange or other suitable reactions with various Lewis acids or their conjugate bases to form the ionic liquid. Examples of suitable heteroaromatic rings include substituted pyridines, imidazole, substituted imidazole, pyrrole and substituted pyrroles. These rings can be alkylated with virtually any straight, branched or cyclic C1-20 alkyl group, but preferably, the alkyl groups are C1-16 groups, since groups larger than this may produce low melting solids rather than ionic liquids. Various triarylphosphines, thioethers and cyclic and non-cyclic quaternary ammonium salts may also be used for this purpose. Counterions that may be used include chloroaluminate, bromoaluminate, gallium chloride, tetrafluoroborate, tetrachloroborate, hexafluorophosphate, nitrate, trifluoromethane sulfonate, methylsulfonate, p-toluenesulfonate, hexafluoroantimonate, hexafluoroarsenate, tetrachloroaluminate, tetrabromoaluminate, perchlorate, hydroxide anion, copper dichloride anion, iron trichloride anion, zinc trichloride anion, as well as various lanthanum, potassium, lithium, nickel, cobalt, manganese, and other metal-containing anions.
Ionic liquids may also be synthesized by salt metathesis, by an acid-base neutralization reaction or by quaternizing a selected nitrogen-containing compound; or they may be obtained commercially from several companies such as Merck (Darmstadt, Germany) or BASF (Mount Olive, N.J.).
Representative examples of ionic liquids useful herein are included among those that are described in sources such as J. Chem. Tech. Biotechnol., 68:351-356 (1997); Chem. Ind., 68:249-263 (1996); J. Phys. Condensed Matter, 5: (supp 34B):B99-B106 (1993); Chemical and Engineering News, Mar. 30, 1998, 32-37; J. Mater. Chem., 8:2627-2636 (1998); Chem. Rev., 99:2071-2084 (1999); and WO 05/113,702 (and references therein cited). In one embodiment, a library, i.e. a combinatorial library, of ionic liquids may be prepared, for example, by preparing various alkyl derivatives of a quaternary nitrogen-containing cation, and varying the associated anions. The acidity of the ionic liquids can be adjusted by varying the molar equivalents and type and combinations of Lewis acids.
In one embodiment, ionic liquids suitable for use herein include those having cations selected from the following formulae:
wherein R1, R2, R3, R4, R5 and R6 are independently selected from the group consisting of:
In another embodiment, ionic liquids useful for the invention comprise fluorinated cations wherein at least one member selected from R1, R2, R3, R4, R5, R6, R7, R8, R9 and R10 comprises F−.
In another embodiment, ionic liquids useful for the invention comprise imidazolium, such as 1-ethyl-3-methylimidazolium and 1-butyl-3-methylimidazolium.
In one embodiment, ionic liquids useful herein have anions selected from the group consisting of [CH3CO2]−, [HSO4]−, [CH3OSO3]−, [C2HSOSO3]−, [AlCl4]−, [CO3]2−, [HCO3]−, [NO2]−, [NO3]−, [SO4]2−, [PO4]3−, [HPO4]2−, [H2PO4]−, [HSO3]−, [CuCl2]−, Cl−, Br−, I−, SCN−; and preferably any fluorinated anion. Fluorinated anions useful herein include [BF4]−, [PF6]−, [SbF6]−, [CF3SO3]−, [HCF2CF2SO3]−, [CF3HFCCF2SO3]−, [HCClFCF2SO3]−, [(CF3SO2)2N]−, [(CF3CF2SO2)2N]−, [(CF3SO2)3C]−, [CF3CO2]−, [CF3OCFHCF2SO3]−, [CF3CF2OCFHCF2SO3]−, [CF3CFHOCF2CF2SO3]−, [CF2HCF2OCF2CF2SO3]−, [CF2ICF2OCF2CF2SO3]−, [CF3CF2OCF2CF2SO3]−, [(CF2HCF2SO2)2N]−, [(CF3CFHCF2SO2)2N]−; and F−.
In another embodiment, ionic liquids suitable for use herein may have a cation selected from the group consisting of pyridinium, pyridazinium, pyrimidinium, pyrazinium, imidazolium, pyrazolium, thiazolium, oxazolium, triazolium, phosphonium, and ammonium as defined above; and an anion selected from the group consisting of [CH3CO2]−, [HSO4]−, [CH3OSO3]−, [C2H5OSO3]−, [AlCl4]−, [CO3]2−, [HCO3]−, [NO2]−, [NO3]−, [SO4]2−, [PO4]3−, [HPO4]2−, [H2PO4]−, [HSO3]−, [CuCl2]−, Cl−, Br−, I−, SCN−, and any fluorinated anion. In yet another embodiment, ionic liquids suitable for use herein may have a cation selected from the group consisting of pyridinium, pyridazinium, pyrimidinium, pyrazinium, imidazolium, pyrazolium, thiazolium, oxazolium, triazolium, phosphonium, and ammonium as defined above; and an anion selected from the group consisting of [BF4]−, [PF6]−, [SbF6]−, [CF3SO3]−, [HCF2CF2SO3]−, [CF3HFCCF2SO3]−, [HCClFCF2SO3]−, [(CF3SO2)2N]−, [(CF3CF2SO2)2N]−, [(CF3SO2)3C]−, [CF3CO2]−, [CF3OCFHCF2SO3]−, [CF3CF2OCFHCF2SO3]−, [CF3CFHOCF2CF2SO3]−, [CF2HCF2OCF2CF2SO3]−, [CF2ICF2OCF2CF2SO3]−, [CF3CF2OCF2CF2SO3]−, [(CF2HCF2SO2)2N]−, [(CF3CFHCF2SO2)2N]−, and F−.
In still another embodiment, ionic liquids suitable for use herein may have a cation selected from the group consisting of pyridinium, pyridazinium, pyrimidinium, pyrazinium, imidazolium, pyrazolium, thiazolium, oxazolium, triazolium, phosphonium, and ammonium as defined above, wherein at least one member selected from R1, R2, R3, R4, R5, R6, R7, R8, R9, and R19 comprises F−; and an anion selected from the group consisting of [CH3CO2]−, [HSO4]−, [CH3OSO3]−, [C2H5OSO3]−, [AlCl4]−, [CO3]2−, [HCO3]−, [NO2]−, [NO3]−, [SO4]2−, [PO4]3−, [HPO4]2−, [H2PO4]−, [HSO3]−, [CuCl2]−, Cl−, Br−, I−, SCN−, and any fluorinated anion. In still another embodiment, ionic liquids suitable for use herein may have a cation selected from the group consisting of pyridinium, pyridazinium, pyrimidinium, pyrazinium, imidazolium, pyrazolium, thiazolium, oxazolium, triazolium, phosphonium, and ammonium as defined above, wherein at least one member selected from R1, R2, R3, R4, R5, R6, R7, R8, R9, and R10 comprises F−; and an anion selected from the group consisting of [BF4]−, [PF6]−, [SbF6]−, [CF3SO3]−, [HCF2CF2SO3]−, [CF3HFCCF2SO3]−, [HCClFCF2SO3]−, [(CF3SO2)2N]−, [(CF3CF2SO2)2N]−, [(CF3SO2)3Cl]−, [CF3CO2]−, [CF3OCFHCF2SO3]−, [CF3CF2OCFHCF2SO3]−, [CF3CFHOCF2CF2SO3]−, [CF2HCF2OCF2CF2SO3]−, [CF2ICF2OCF2CF2SO3]−, [CF3CF2OCF2CF2SO3]−, [(CF2HCF2SO2)2N]−, [(CF3CFHCF2SO2)2N]−, and F−.
In one embodiment, the ionic liquid comprises imidazolium as the cation and [BF4]− or [PF6]− as the anion. In another embodiment, the ionic liquid comprises 1-ethyl-3-methylimidazolium (also referred to herein as Emim) or 1-butyl-3-methylimidazolium (also referred to herein as Bmim) as the cation, and [BF4]− or [PF6]− as the anion.
In one embodiment, the present compositions comprise at least one ionic liquid and at least one fluoroolefin. In some embodiments, fluoroolefins are compounds, which comprise carbon atoms, fluorine atoms and optionally hydrogen or chlorine atoms. In one embodiment, the fluoroolefins used in the compositions of the present invention comprise compounds with 2 to 12 carbon atoms. In another embodiment the fluoroolefins comprise compounds with 3 to 10 carbon atoms, and in yet another embodiment the fluoroolefins comprise compounds with 3 to 7 carbon atoms. Representative fluoroolefins include but are not limited to all compounds as listed in Table 1, Table 2, and Table 3.
One embodiment of the present invention provides fluoroolefins having the formula E- or Z—R1CH═CHR2 (Formula I), wherein R1 and R2 are, independently, C1 to C6 perfluoroalkyl groups. Examples of R1 and R2 groups include, but are not limited to, CF3, C2F5, CF2CF2CF3, CF(CF3)2, CF2CF2CF2CF3, CF(CF3)CF2CF3, CF2CF(CF3)2, C(CF3)3, CF2CF2CF2CF2CF3, CF2CF2CF(CF3)2, C(CF3)2C2F5, CF2CF2CF2CF2CF2CF3, CF(CF3)CF2CF2C2F5, and C(CF3)2CF2C2F5. In one embodiment the fluoroolefins of Formula I have at least 4 carbon atoms in the molecule. In another embodiment, the fluoroolefins of Formula I have at least 5 carbon atoms in the molecule. Exemplary, non-limiting Formula I compounds are presented in Table 1.
Compounds of Formula I may be prepared by contacting a perfluoroalkyl iodide of the formula R1I with a perfluoroalkyltrihydroolefin of the formula R2CH═CH2 to form a trihydroiodoperfluoroalkane of the formula R1CH2CHIR2. This trihydroiodoperfluoroalkane can then be dehydroiodinated to form R1CH═CHR2. Alternatively, the olefin R1CH═CHR2 may be prepared by dehydroiodination of a trihydroiodoperfluoroalkane of the formula R1CHICH2R2 formed in turn by reacting a perfluoroalkyl iodide of the formula R2I with a perfluoroalkyltrihydroolefin of the formula R1CH═CH2.
The contacting of a perfluoroalkyl iodide with a perfluoroalkyltrihydroolefin may take place in batch mode by combining the reactants in a suitable reaction vessel capable of operating under the autogenous pressure of the reactants and products at reaction temperature. Suitable reaction vessels include fabricated from stainless steels, in particular of the austenitic type, and the well-known high nickel alloys such as Monel® nickel-copper alloys, Hastelloy® nickel based alloys and Inconel® nickel-chromium alloys.
Alternatively, the reaction may take be conducted in semi-batch mode in which the perfluoroalkyltrihydroolefin reactant is added to the perfluoroalkyl iodide reactant by means of a suitable addition apparatus such as a pump at the reaction temperature.
The ratio of perfluoroalkyl iodide to perfluoroalkyltrihydroolefin should be between about 1:1 to about 4:1, preferably from about 1.5:1 to 2.5:1. Ratios less than 1.5:1 tend to result in large amounts of the 2:1 adduct as reported by Jeanneaux, et. al. in Journal of Fluorine Chemistry, Vol. 4, pages 261-270 (1974).
Preferred temperatures for contacting of said perfluoroalkyl iodide with said perfluoroalkyltrihydroolefin are preferably within the range of about 150° C. to 300° C., preferably from about 170° C. to about 250° C., and most preferably from about 180° C. to about 230° C.
Suitable contact times for the reaction of the perfluoroalkyl iodide with the perfluoroalkyltrihydroolefin are from about 0.5 hour to 18 hours, preferably from about 4 to about 12 hours.
The trihydroiodoperfluoroalkane prepared by reaction of the perfluoroalkyl iodide with the perfluoroalkyltrihydroolefin may be used directly in the dehydroiodination step or may preferably be recovered and purified by distillation prior to the dehydroiodination step.
The dehydroiodination step is carried out by contacting the trihydroiodoperfluoroalkane with a basic substance. Suitable basic substances include alkali metal hydroxides (e.g., sodium hydroxide or potassium hydroxide), alkali metal oxide (for example, sodium oxide), alkaline earth metal hydroxides (e.g., calcium hydroxide), alkaline earth metal oxides (e.g., calcium oxide), alkali metal alkoxides (e.g., sodium methoxide or sodium ethoxide), aqueous ammonia, sodium amide, or mixtures of basic substances such as soda lime. Preferred basic substances are sodium hydroxide and potassium hydroxide.
Said contacting of the trihydroiodoperfluoroalkane with a basic substance may take place in the liquid phase preferably in the presence of a solvent capable of dissolving at least a portion of both reactants. Solvents suitable for the dehydroiodination step include one or more polar organic solvents such as alcohols (e.g., methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, and tertiary butanol), nitriles (e.g., acetonitrile, propionitrile, butyronitrile, benzonitrile, or adiponitrile), dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, or sulfolane. The choice of solvent may depend on the boiling point product and the ease of separation of traces of the solvent from the product during purification. Typically, ethanol or isopropanol are good solvents for the reaction.
Typically, the dehydroiodination reaction may be carried out by addition of one of the reactants (either the basic substance or the trihydroiodoperfluoroalkane) to the other reactant in a suitable reaction vessel. Said reaction may be fabricated from glass, ceramic, or metal and is preferably agitated with an impeller or stirring mechanism.
Temperatures suitable for the dehydroiodination reaction are from about 10° C. to about 100° C., preferably from about 20° C. to about 70° C. The dehydroiodination reaction may be carried out at ambient pressure or at reduced or elevated pressure. Of note are dehydroiodination reactions in which the compound of Formula I is distilled out of the reaction vessel as it is formed.
Alternatively, the dehydroiodination reaction may be conducted by contacting an aqueous solution of said basic substance with a solution of the trihydroiodoperfluoroalkane in one or more organic solvents of lower polarity such as an alkane (e.g., hexane, heptane, or octane), aromatic hydrocarbon (e.g., toluene), halogenated hydrocarbon (e.g., methylene chloride, chloroform, carbon tetrachloride, or perchloroethylene), or ether (e.g., diethyl ether, methyl tert-butyl ether, tetrahydrofuran, 2-methyl tetrahydrofuran, dioxane, dimethoxyethane, diglyme, or tetraglyme) in the presence of a phase transfer catalyst. Suitable phase transfer catalysts include quaternary ammonium halides (e.g., tetrabutylammonium bromide, tetrabutylammonium hydrosulfate, triethylbenzylammonium chloride, dodecyltrimethylammonium chloride, and tricaprylylmethylammonium chloride), quaternary phosphonium halides (e.g., triphenylmethylphosphonium bromide and tetraphenylphosphonium chloride), or cyclic polyether compounds known in the art as crown ethers (e.g., 18-crown-6 and 15-crown-5).
Alternatively, the dehydroiodination reaction may be conducted in the absence of solvent by adding the trihydroiodoperfluoroalkane to a solid or liquid basic substance.
Suitable reaction times for the dehydroiodination reactions are from about 15 minutes to about six hours or more depending on the solubility of the reactants. Typically the dehydroiodination reaction is rapid and requires about 30 minutes to about three hours for completion.
The compound of Formula I may be recovered from the dehydroiodination reaction mixture by phase separation after addition of water, by distillation, or by a combination thereof.
In another embodiment of the present invention, fluoroolefins comprise cyclic fluoroolefins (cyclo-[CX═CY(CZW)n-] (Formula II), wherein X, Y, Z, and W are independently selected from H and F, and n is an integer from 2 to 5). In one embodiment the fluoroolefins of Formula II, have at least about 3 carbon atoms in the molecule. In another embodiment, the fluoroolefins of Formula II have at least about 4 carbon atoms in the molecule. In yet another embodiment, the fluoroolefins of Formula II have at least about 5 carbon atoms in the molecule. Representative cyclic fluoroolefins of Formula II are listed in Table 2.
The compositions of the present invention may comprise a single compound of Formula I or Formula II, for example, one of the compounds in Table 1 or Table 2, or may comprise a combination of compounds of Formula I or Formula II.
In another embodiment, fluoroolefins may comprise those compounds listed in Table 3.
The compounds listed in Table 2 and Table 3 are available commercially or may be prepared by processes known in the art or as described herein.
1,1,1,4,4-pentafluoro-2-butene may be prepared from 1,1,1,2,4,4-hexafluorobutane (CHF2CH2CHFCF3) by dehydrofluorination over solid KOH in the vapor phase at room temperature. The synthesis of 1,1,1,2,4,4-hexafluorobutane is described in U.S. Pat. No. 6,066,768. 1,1,1,4,4,4-hexafluoro-2-butene may be prepared from 1,1,1,4,4,4-hexafluoro-2-iodobutane (CF3CHICH2CF3) by reaction with KOH using a phase transfer catalyst at about 60° C. The synthesis of 1,1,1,4,4,4-hexafluoro-2-iodobutane may be carried out by reaction of perfluoromethyl iodide (CF3I) and 3,3,3-trifluoropropene (CF3CH═CH2) at about 200° C. under autogenous pressure for about 8 hours.
3,4,4,5,5,5-hexafluoro-2-pentene may be prepared by dehydrofluorination of 1,1,1,2,2,3,3-heptafluoropentane (CF3CF2CF2CH2CH3) using solid KOH or over a carbon catalyst at 200-300° C. 1,1,1,2,2,3,3-heptafluoropentane may be prepared by hydrogenation of 3,3,4,4,5,5,5-heptafluoro-1-pentene (CF3CF2CF2CH═CH2).
1,1,1,2,3,4-hexafluoro-2-butene may be prepared by dehydrofluorination of 1,1,1,2,3,3,4-heptafluorobutane (CH2FCF2CHFCF3) using solid KOH.
1,1,1,2,4,4-hexafluoro-2-butene may be prepared by dehydrofluorination of 1,1,1,2,2,4,4-heptafluorobutane (CHF2CH2CF2CF3) using solid KOH.
1,1,1,3,4,4-hexafluoro2-butene may be prepared by dehydrofluorination of 1,1,1,3,3,4,4-heptafluorobutane (CF3CH2CF2CHF2) using solid KOH.
1,1,1,2,4-pentafluoro-2-butene may be prepared by dehydrofluorination of 1,1,1,2,2,3-hexafluorobutane (CH2FCH2CF2CF3) using solid KOH.
1,1,1,3,4-pentafluoro-2-butene may be prepared by dehydrofluorination of 1,1,1,3,3,4-hexafluorobutane (CF3CH2CF2CH2F) using solid KOH.
1,1,1,3-tetrafluoro-2-butene may be prepared by reacting 1,1,1,3,3-pentafluorobutane (CF3CH2CF2CH3) with aqueous KOH at 120° C.
1,1,1,4,4,5,5,5-octafluoro-2-pentene may be prepared from (CF3CHICH2CF2CF3) by reaction with KOH using a phase transfer catalyst at about 60° C. The synthesis of 4-iodo-1,1,1,2,2,5,5,5-octafluoropentane may be carried out by reaction of perfluoroethyliodide (CF3CF2I) and 3,3,3-trifluoropropene at about 200° C. under autogenous pressure for about 8 hours.
1,1,1,2,2,5,5,6,6,6-decafluoro-3-hexene may be prepared from 1,1,1,2,2,5,5,6,6,6-decafluoro-3-iodohexane (CF3CF2CHICH2CF2CF3) by reaction with KOH using a phase transfer catalyst at about 60° C. The synthesis of 1,1,1,2,2,5,5,6,6,6-decafluoro-3-iodohexane may be carried out by reaction of perfluoroethyliodide (CF3CF2I) and 3,3,4,4,4-pentafluoro-1-butene (CF3CF2CH═CH2) at about 200° C. under autogenous pressure for about 8 hours.
1,1,1,4,5,5,5-heptafluoro-4-(trifluoromethyl)-2-pentene may be prepared by the dehydrofluorination of 1,1,1,2,5,5,5-heptafluoro-4-iodo-2-(trifluoromethyl)-pentane (CF3CHICH2CF(CF3)2) with KOH in isopropanol. CF3CHICH2CF(CF3)2 is made from reaction of (CF3)2CFI with CF3CH═CH2 at high temperature, such as about 200° C.
1,1,1,4,4,5,5,6,6,6-decafluoro-2-hexene may be prepared by the reaction of 1,1,1,4,4,4-hexafluoro-2-butene (CF3CH═CHCF3) with tetrafluoroethylene (CF2═CF2) and antimony pentafluoride (SbF5).
2,3,3,4,4-pentafluoro-1-butene may be prepared by dehydrofluorination of 1,1,2,2,3,3-hexafluorobutane over fluorided alumina at elevated temperature.
2,3,3,4,4,5,5,5-ocatafluoro-1-pentene may be prepared by dehydrofluorination of 2,2,3,3,4,4,5,5,5-nonafluoropentane over solid KOH.
1,2,3,3,4,4,5,5-octafluoro-1-pentene may be prepared by dehydrofluorination of 2,2,3,3,4,4,5,5,5-nonafluoropentane over fluorided alumina at elevated temperature.
Many of the compounds of Formula I, Formula II, Table 1, Table 2 and Table 3 exist as different configurational isomers or stereoisomers. When the specific isomer is not designated, the present invention is intended to include all single configurational isomers, single stereoisomers, or any combination thereof. For instance, F11E is meant to represent the E-isomer, Z-isomer, or any combination or mixture of both isomers in any ratio. As another example, HFO-1225ye is meant to represent the E-isomer, Z-isomer, or any combination or mixture of both isomers in any ratio.
In one embodiment, disclosed is a composition comprising at least one fluoroolefin selected from the group consisting of HFO-1234yf, E-HFO-1234ze (trans), HFO-1243zf, F12E (E- or Z-isomer), HFO-1233xd, HFO-1233zf, E-F11E, Z-F11E, F22E (E- or Z-isomer), F24E (E- or Z-isomer), F33E (E- or Z-isomer), HFO-1429myz, HFO-1429mzy, HFO-1447fzy (PFBE), HFO-162-13mczy, HFO-162-13mcyz, and mixtures thereof; and an effective amount of at least one ionic liquid.
In one embodiment, the compositions comprise at least about 1 weight percent of at least one fluoroolefin. In another embodiment, the compositions comprise from about 1 weight percent to about 99 weight percent of at least one ionic liquid and from about 99 weight percent to about 1 weight percent at least one fluoroolefin. In another embodiment, the compositions comprise from about 20 weight percent to about 99 weight percent of at least one ionic liquid and from about 80 weight percent to about 1 weight percent at least one fluoroolefin. In another embodiment, the compositions comprise from about 20 weight percent to about 60 weight percent of at least one ionic liquid and from about 80 weight percent to about 40 weight percent at least one fluoroolefin. In yet another embodiment, the compositions comprise from about 20 weight percent to about 50 weight percent of at least one ionic liquid and from about 80 weight percent to about 50 weight percent at least one fluoroolefin.
In certain embodiments, the disclosed compositions may further comprise additional refrigerants selected from the group consisting of hydrofluorocarbons, fluoroethers, hydrochlorofluorocarbons, chlorofluorocarbons, perfluorocarbons, hydrocarbons, CF3I, NH3, CO2, and mixtures thereof, meaning mixtures of any of the foregoing compounds. In one particular embodiment, the composition of the present invention may comprise at least one ionic liquid, at least one fluoroolefin, and at least one hydrofluorocarbon.
Hydrofluorocarbons comprise at least one saturated compound containing carbon, hydrogen, and fluorine. Of particular utility are hydrofluorocarbons having 1-7 carbon atoms and having a normal boiling point of from about −90° C. to about 80° C. Hydrofluorocarbons are commercial products available from a number of sources or may be prepared by methods known in the art. Representative hydrofluorocarbon compounds include but are not limited to fluoromethane (CH3F, HFC-41), difluoromethane (CH2F2, HFC-32), trifluoromethane (CHF3, HFC-23), pentafluoroethane (CF3CHF2, HFC-125), 1,1,2,2-tetrafluoroethane (CHF2CHF2, HFC-134), 1,1,1,2-tetrafluoroethane (CF3CH2F, HFC-134a), 1,1,1-trifluoroethane (CF3CH3, HFC-143a), 1,1-difluoroethane (CHF2CH3, HFC-152a), fluoroethane (CH3CH2F, HFC-161), 1,1,1,2,2,3,3-heptafluoropropane (CF3CF2CHF2, HFC-227ca), 1,1,1,2,3,3,3-heptafluoropropane (CF3CHFCF3, HFC-227ea), 1,1,2,2,3,3,-hexafluoropropane (CHF2CF2CHF2, HFC-236ca), 1,1,1,2,2,3-hexafluoropropane (CF3CF3CH2F, HFC-236cb), 1,1,1,2,3,3-hexafluoropropane (CF3CHFCHF2, HFC-236ea), 1,1,1,3,3,3-hexafluoropropane (CF3CH2CF3, HFC-236fa), 1,1,2,2,3-pentafluoropropane (CHF2CF2CH2F, HFC-245ca), 1,1,1,2,2-pentafluoropropane (CF3CF2CH3, HFC-245cb), 1,1,2,3,3-pentafluoropropane (CHF2CHFCHF2, HFC-245ea), 1,1,1,2,3-pentafluoropropane (CF3CHFCH2F, HFC-245eb), 1,1,1,3,3-pentafluoropropane (CF3CH2CHF2, HFC-245fa), 1,2,2,3-tetrafluoropropane (CH2FCF2CH2F, HFC-254ca), 1,1,2,2-tetrafluoropropane (CHF2CF2CH3, HFC-254cb), 1,1,2,3-tetrafluoropropane (CHF2CHFCH2F, HFC-254ea), 1,1,1,2-tetrafluoropropane (CF3CHFCH3, HFC-254eb), 1,1,3,3-tetrafluoropropane (CHF2CH2CHF2, HFC-254fa), 1,1,1,3-tetrafluoropropane (CF3CH2CH2F, HFC-254fb), 1,1,1-trifluoropropane (CF3CH2CH3, HFC-263fb), 2,2-difluoropropane (CH3CF2CH3, HFC-272ca), 1,2-difluoropropane (CH2FCHFCH3, HFC-272ea), 1,3-difluoropropane (CH2FCH2CH2F, HFC-272fa), 1,1-difluoropropane (CHF2CH2CH3, HFC-272fb), 2-fluoropropane (CH3CHFCH3, HFC-281ea), 1-fluoropropane (CH2FCH2CH3, HFC-281fa), 1,1,2,2,3,3,4,4-octafluorobutane (CHF2CF2CF2CHF2, HFC-338 pcc), 1,1,1,2,2,4,4,4-octafluorobutane (CF3CH2CF2CF3, HFC-338mf), 1,1,1,3,3-pentafluorobutane (CF3CH2CHF2, HFC-365mfc), 1,1,1,2,3,4,4,5,5,5-decafluoropentane (CF3CHFCHFCF2CF3, HFC-43-10mee), and 1,1,1,2,2,3,4,5,5,6,6,7,7,7-tetradecafluoroheptane (CF3CF2CHFCHFCF2CF2CF3, HFC-63-14mee).
In some embodiments, the disclosed compositions may further comprise fluoroethers. Fluoroethers comprise at least one compound having carbon, fluorine, oxygen and optionally hydrogen, chlorine, bromine or iodine. Fluoroethers are commercially available or may be produced by methods known in the art. Representative fluoroethers include but are not limited to nonafluoromethoxybutane (C4F9OCH3, any or all possible isomers or mixtures thereof); nonafluoroethoxybutane (C4F9OC2H5, any or all possible isomers or mixtures thereof); 2-difluoromethoxy-1,1,1,2-tetrafluoroethane (HFOC-236eaEβγ, or CHF2OCHFCF3); 1,1-difluoro-2-methoxyethane (HFOC-272fbEβγ, CH3OCH2CHF2); 1,1,1,3,3,3-hexafluoro-2-(fluoromethoxy)propane (HFOC-347 mmzEβγ, or CH2FOCH(CF3)2); 1,1,1,3,3,3-hexafluoro-2-methoxypropane (HFOC-356 mmzEβγ, or CH3OCH(CH3)2); 1,1,1,2,2-pentafluoro-3-methoxypropane (HFOC-365mcEγδ, or CF3CF2CH2OCH3); 2-ethoxy-1,1,1,2,3,3,3-heptafluoropropane (HFOC-467 mmyEβγ, or CH3CH2OCF(CF3)2; and mixtures thereof.
In some embodiments, the disclosed compositions may further comprise hydrochlorofluorocarbons. Hydrochlorofluorocarbons (HCFCs) comprise compounds having carbon, hydrogen, chlorine and fluorine in the molecule. In one embodiment, HCFCs comprise compounds having from 1 to 3 carbons per molecule. Representative HCFCs include, chlorodifluoromethane (HCFC-22, CHF2Cl), 2,2-dichloro-1,1,1-trifluoroethane (HCFC-123, CHCl2CF3), 2-chloro-1,1,1,2-tetrafluoroethane (HCFC-124, CHFClCF3), and mixtures thereof.
In some embodiments, the disclosed compositions may further comprise chlorofluorocarbons (CFCs). Chlorofluorocarbons comprise compounds having carbon, chlorine and fluorine in the molecule. In one embodiment, CFCs comprise compounds having from 1-3 carbon atoms. Representative CFCs include fluorotrichloromethane (CFC-11, CFCl3), dichlorodifluoromethane (CFC-12, CF2Cl2) 1,2-dichloro-1,1,2,2-difluoroethane (CFC-114, CF2ClCF2Cl), 2,2-dichloro-1,1,1,2-tetrafluoroethane (CFC-114a, CFCl2CF3), 1,1,2-trichloro-1,2,2-trifluoroethane (CFC-113, CFCl2CF2Cl), and mixtures thereof.
In some embodiments, the disclosed compositions may further comprise perfluorocarbons (sometimes referred to simply as fluorocarbons). Perfluorocarbons (PFCs or FCs) comprise compounds having carbon and fluorine only in the molecule. In one embodiment, PFCs comprise compounds having from 1-4 carbon atoms. Representative PFCs include tetrafluoromethane (PFC-14, CF4), hexafluoroethane (PFC-116, CF3CF3), tetrafluoroethylene (TFE, CF2═CF2), octafluoropropane (PFC-218, CF3CF2CF3), octafluorocyclobutane (PF-C318, cyclo-CF2CF2CF2CF2—), and mixtures thereof.
In some embodiments, the disclosed compositions may further comprise at least one hydrocarbon. Hydrocarbons are compounds having only carbon and hydrogen. Of particular utility are compounds having 3-7 carbon atoms. Hydrocarbons are commercially available through numerous chemical suppliers. Representative hydrocarbons include but are not limited to propane, n-butane, isobutane, cyclobutane, n-pentane, 2-methylbutane, 2,2-dimethylpropane, cyclopentane, n-hexane, 2-methylpentane, 2,2-dimethylbutane, 2,3-dimethylbutane, 3-methylpentane, cyclohexane, n-heptane, cycloheptane, and mixtures thereof. In some embodiments, the disclosed compositions may comprise hydrocarbons containing heteroatoms, such as dimethylether (DME, CH3OCH3). DME is commercially available.
In some embodiments, the disclosed compositions may further comprise carbon dioxide (CO2), which is commercially available from various sources or may be prepared by methods known in the art.
In some embodiments, the disclosed compositions may further comprise ammonia (NH3), which is commercially available from various sources or may be prepared by methods known in the art.
In some embodiments, the disclosed compositions may further comprise iodotrifluoromethane (CF3I), which is commercially available from various sources or may be prepared by methods known in the art.
In some embodiment, the compositions may comprise azeotrope or near-azeotrope compositions comprising a fluoroolefin and one of the other compounds as described previously herein selected from hydrofluorocarbons, hydrofluorocarbon ethers, hydrocarbons, CO2, NH3, and CF3I.
As used herein, an azeotropic composition comprises a constant-boiling mixture of two or more substances that behave as a single substance. One way to characterize an azeotropic composition is that the vapor produced by partial evaporation or distillation of the liquid has the same composition as the liquid from which it is evaporated or distilled, i.e., the mixture distills/refluxes without compositional change. Constant-boiling compositions are characterized as azeotropic because they exhibit either a maximum or minimum boiling point, as compared with that of the non-azeotropic mixture of the same compounds. An azeotropic composition will not fractionate within a heat transfer system during operation, which may reduce efficiency of the system. Additionally, an azeotropic composition will not fractionate upon leakage from a heat transfer system.
As used herein, a near-azeotropic composition (also commonly referred to as an “azeotrope-like composition”) comprises a substantially constant boiling liquid admixture of two or more substances that behaves similarly to a single substance. One way to characterize a near-azeotropic composition is that the vapor produced by partial evaporation or distillation of the liquid has substantially the same composition as the liquid from which it was evaporated or distilled, that is, the admixture distills/refluxes without substantial composition change. Another way to characterize a near-azeotropic composition is that the bubble point vapor pressure and the dew point vapor pressure of the composition at a particular temperature are substantially the same. As used herein, a composition is near-azeotropic if, after 50 weight percent of the composition is removed, such as by evaporation or boiling off, the difference in vapor pressure between the original composition and the composition remaining after 50 weight percent of the original composition has been removed is less than about 10 percent.
In another embodiment, disclosed are compositions comprising at least one ionic liquid and various salts including LiBr. Mixtures of ionic liquids or mixtures of ionic liquids and salts may be used to achieve proper absorption, transport or other properties.
In another embodiment, the disclosed compositions may further comprise additives, including lubricants, corrosion inhibitors, crystallization inhibitors, stabilizers, solubilizers, dyes, viscosity modifiers, wetting agents, defoaming agents and surfactants, and mixtures thereof.
A typical vapor compression heat transfer system is shown generally at 50 in
In one embodiment, disclosed herein are refrigerant and absorbent compositions that may be useful for a wide range of absorption cooling applications spanning from low temperature refrigeration to comfort air conditioning.
The working fluid pair compositions are useful in the execution of an absorption cycle. A schematic diagram for one embodiment, of a simple absorption cooling system is shown in
In a typical absorption cycle system, cooling is accomplished by absorbing and then releasing water vapor into and out of a lithium bromide (LiBr) solution. These absorption chillers operate at a partial vacuum (about 1/100th of normal atmospheric pressure) to cause water to vaporize at a cold enough temperature (about 40° F.) to produce chilled water at about 44° F. The compositions disclosed herein may be used in similar systems either at vacuum or above atmospheric pressure, depending upon the physical properties of the refrigerant and absorbent being used. For low boiling fluoroolefin refrigerants, the pressure will be above atmospheric and still allow the system to produce cooling. Referring to
In the condenser 5, cooling water is moving through the tubes and the refrigerant vapor condenses to form refrigerant liquid on the outside of the tubes that collects in a trough 6 at the bottom of the condenser. The refrigerant liquid moves from the condenser trough via line 17 to the evaporator 7 through an expansion device 8 that partially evaporates the refrigerant liquid. The partially evaporated refrigerant liquid contacts the tubes of the evaporator which have water or some other heat transfer fluid flowing therethrough. The heat transfer fluid is cooled as the liquid refrigerant is evaporated forming refrigerant vapor. The cooled heat transfer fluid is circulated back to a body to be cooled, such as a building, thus providing the cooling effect as desired for instance for air conditioning. The refrigerant vapor migrates to the absorber from the evaporator. The high affinity of the absorbent for the refrigerant causes the refrigerant to be dissolved into the absorbent/refrigerant solution. The absorption of the refrigerant into the absorbent also generates heat (heat of absorption). Cooling water moves through the tube bundles of the absorber to remove this heat of absorption from the system. The solution collecting at the bottom of the absorber is again a high refrigerant absorbent/refrigerant solution that will begin the cycle again.
Cooling water is used in both the absorber and condenser as described above. The cooling water will flow into the system at the absorber at 13, wherein it warms slightly due to the heat of solution of the refrigerant dissolving into the absorbent. From the absorber, the cooling water will move via line 14 to the condenser tube bundle wherein it will provide the cooling to condense the refrigerant vapor to refrigerant liquid. The cooling water is thus heated somewhat again and from the condenser flows via line 15 to a cooling tower or other device intended to release the heat picked up in the system to the atmosphere and provide cooled water again to the system.
The hot water, steam, or combustion gasses supplied to the generator in order to release refrigerant vapor from the absorbent/refrigerant solution may be supplied by any number of sources, including water heated with waste heat from a combustion engine (combustion gases) and solar heated water, among others.
In one embodiment, disclosed herein is a process for producing cooling comprising forming a refrigerant/absorbent mixture, heating said mixture to release refrigerant vapor, condensing said refrigerant to form liquid refrigerant, evaporating said liquid refrigerant in the vicinity of a heat transfer fluid, transferring said heat transfer fluid to the vicinity of a body to be cooled, and reforming the absorbent/refrigerant solution.
A body to be cooled may be any space, location, object or body which it is desirable to cool, including the interior spaces of buildings requiring air conditioning, and refrigerator or freezer spaces, in for instance hotels or restaurants, or industrial process areas for example used to process or produce food products.
In another embodiment, in a similar manner to the process described above to produce cooling, an absorption cycle may be used to generate heat with for instance an absorption heat pump. In this process the heat of solution generated by dissolving the refrigerant into the absorbent in the absorber and the heat of condensation generated by condensing the refrigerant vapor to refrigerant liquid in the condenser can be transferred to water or some other heat transfer fluid, which is used to heat any space, location, object or body.
In another embodiment, disclosed herein is a process for transferring heat comprising moving a heat transfer fluid from a heat source to a heat sink, wherein the heat source is an absorption cycle utilizing a working fluid pair comprising at least one ionic liquid and at least one fluoroolefin. In this process, the heat sink is any space, location, object, or body requiring heating, including the interior spaces of buildings requiring heating, and industrial processes, among others.
In another embodiment, disclosed herein is a process for transferring heat comprising moving a heat transfer fluid from a heat sink to a heat source, wherein the heat sink is an absorption cycle utilizing a working fluid pair comprising at least one ionic liquid and at least one fluoroolefin. In this process, the heat source is any space, location, object, or body requiring cooling, including the interior spaces of buildings requiring cooling, and industrial processes, among others.
In one embodiment, disclosed herein is an absorption cycle system apparatus comprising an absorber, a generator, a condenser, an expansion device, and an evaporator, wherein the working fluids contained within said apparatus comprise at least one ionic liquid and at least one fluoroolefin.
In one embodiment, the disclosed apparatus is similar in arrangement to that shown in
In another embodiment, disclosed herein is an absorption cycle apparatus comprising an absorber, a generator, a condenser, an expansion device, and an evaporator; wherein the working fluids contained within said apparatus comprise at least one ionic liquid and at least one fluoroolefin; and wherein said apparatus is an absorption chiller.
In another embodiment, disclosed herein is an absorption cycle apparatus comprising an absorber, a generator, a condenser, an expansion device, and an evaporator; wherein the working fluids contained within said apparatus comprise at least one ionic liquid and at least one fluoroolefin; and wherein said apparatus is an absorption heat pump.
The concepts disclosed herein will be further described in the following examples, which do not limit the scope of the invention described in the claims.
Samples containing 9.4 and 17.3 mole percent trans-HFO-1336m/z in 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ionic liquid (abbreviated [emim][Tf2N]) were prepared and the pressure was measured at temperatures ranging from 20° C. to 80° C. The data is shown in
The fluoroolefin trans-HFO-1336mzz was prepared by reaction of CF3I with 3,3,3-trifluoropropene (CF3CH═CH2) to produce CF3CH2CHICF3, which was then reacted KOH to form the CF3CH═CHCF3 (as described herein as well as in J. of Fluorine Chemistry, 4 (1974), 261-270.). The ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [emim][Tf2N], (electrochemical grade, ≧99.5%, C8H11F6N3O4S2) was purchased from Covalent Associates Inc. (Corvallis, Oreg.).
The data in Table 4 indicates that the trans-HFO-1336mzz is soluble in the ionic liquid [emim][Tf2N] indicating that these compounds would function as a working fluid pair (refrigerant and absorbent) in an absorption cycle system.
Samples containing 28.0, 58.9, and 100 mole percent cis-HFO-1336mzz in 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ionic liquid, (abbreviated [emim][Tf2N]) were prepared and the pressure was measured at temperatures ranging from 20° C. to 80° C. The data is shown in
The fluoroolefin cis-HFO-1336mzz was prepared by hydrogenation of hexafluoro-2-butyne (CF3C≡CCF3) using a Lindlar catalyst, as described in detail in U.S. Patent Publication No. 2008-0269532 A1. The ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [emim][Tf2N], (electrochemical grade, ≧99.5%, C8H11F6N3O4S2) was purchased from Covalent Associates Inc. (Corvallis, Oreg.).
The data in Table 5 indicates that the cis-HFO-1336mzz is soluble in the ionic liquid [emim][Tf2N] indicating that these compounds would function as a working fluid pair (refrigerant and absorbent) in an absorption cycle system.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/US2009/049869 | 7/8/2009 | WO | 00 | 12/15/2010 |
| Number | Date | Country | |
|---|---|---|---|
| 61078981 | Jul 2008 | US |
