Compositions comprising 1,1,1,2,3-pentafluoropropane or 2,3,3,3-tetrafluoropropene

Abstract

Disclosed are compositions comprising HFC-245eb and at least one additional compound selected from the group consisting of hfo-1234ze, HFC-245fa, HFC-236cb, HFC-236ea, HFC-236fa, HFC-227ea, HFC-227ca, hfo-1225yc, hfo-1225zc, hfo-1225ye, methane, ethane, propane, HFC-23, HFC-143a, HFC-134, HFC-134a, FC-1216, hfo-1234yf, HFC-254eb, hfo-1243zf, and HFC-254fb. compositions comprising HFC-245eb are useful in processes to make hfo-1234yf. Also disclosed are compositions comprising hfo-1234yf and at least one additional compound selected from the group consisting of hfo-1234ze, HFC-254eb, HFC-254fb, hfo-1243zf, HFCHFC-245eb, HFC-245fa, HFC-245cb, HFC-236cb, HFC-236ea, HFC-236fa, HFC-227ea, HFC-227ca, hfo-1225yc, hfo-1225zc, hfo-1225ye, methane, ethane, propane, HFC-23, HFC-134, HFC-134a, hfo-1132a and FC-1216. compositions comprising hfo-1234yf are useful as heat transfer compositions for use in refrigeration, air-conditioning and heat pump systems.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

where Δ represents heat, and HF is hydrogen fluoride.

HFC-245eb can be prepared by the hydrogenation of CF₃CClFCCl₂F (CFC-215bb) over a palladium on carbon catalyst as disclosed in International Application No. PCT/US07/14646, filed Jun. 22, 2007 and published as WO2008/002501 on Jan. 3, 2008, or by the hydrogenation of CF₃CF═CFH as disclosed in U.S. Pat. No. 5,396,000.

Pyrolysis, as the term is used herein, means chemical change produced by heating in the absence of catalyst. Pyrolysis reactors generally comprise three zones: a) a preheat zone, in which reactants are brought close to the reaction temperature; b) a reaction zone, in which reactants reach reaction temperature and are at least partially pyrolyzed, and products and any byproducts form; c) a quench zone, in which the stream exiting the reaction zone is cooled to stop the pyrolysis reaction. Laboratory-scale reactors have a reaction zone, but the preheating and quenching zones may be omitted.

The reactor for carrying out the pyrolysis may be of any shape consistent with the process but is preferably a cylindrical tube, either straight or coiled. Although not critical, such reactors typically have an inner diameter of from about 1.3 to about 5.1 cm (about 0.5 to about 2 inches). Heat is applied to the outside of the tube, the chemical reaction taking place on the inside of the tube. The reactor and its associated feed lines, effluent lines and associated units should be constructed, at least as regards the surfaces exposed to the reactants and products, of materials resistant to hydrogen fluoride. Typical materials of construction include stainless steels, in particular of the austenitic type, the well-known high nickel alloys, such as nickel-copper alloys commercially available from Special Metals Corp. (New Hartford, N.Y.) under the trademark Monel®, nickel-based alloys commercially available from Haynes International (Kokomo, Ind.) under the trademark Hastelloy® (hereinafter referred to as “Hastelloy®”) and nickel-chromium alloys commercially available from Special Metals Corp. under the trademark Inconel®, and copper-clad steel.

Where the reactor is exposed to high temperature the reactor may be constructed of more than one material. For example, the outer surface layer of the reactor should be chosen for ability to maintain structural integrity and resist corrosion at the pyrolysis temperature, the inner surface layer of the reactor should be chosen of materials resistant to attack by, that is, inert to, the reactant and products. In the case of the present process, the product hydrogen fluoride is corrosive to certain materials. Thus, the reactor may be constructed of an outer material chosen for physical strength at high temperature and an inner material chosen for resistance to corrosion by the reactants and products under the temperature of the pyrolysis.

In one embodiment, the reactor inner surface layer is made of high nickel alloy, that is an alloy containing at least about 50 wt % nickel, preferably a nickel alloy having at least about 75 wt % nickel, more preferably a nickel alloy having less than about 8 wt % chromium, still more preferably a nickel alloy having at least about 98 wt % nickel, and most preferably substantially pure nickel, such as the commercial grade known as Nickel 200. More preferable than nickel or its alloys as the material for the inner surface layer of the reactor is gold. The thickness of the inner surface layer does not substantially affect the pyrolysis and is not critical so long as the integrity of the inner surface layer is intact. The thickness of the inner surface layer is typically from about 10 to about 100 mils (0.25 to 2.5 mm). The thickness of the inner surface layer can be determined by the method of fabrication, the cost of materials, and the desired reactor life.

In one embodiment, the reactor outer surface layer is resistant to oxidation or other corrosion and maintains sufficient strength at the reaction temperatures to keep the reaction vessel from failing of distorting. In one embodiment, this layer is a nickel, iron, chromium alloy sold by Special Metals Corp. (New Hartford, N.Y.) under the trademark Inconel®. In another embodiment, this layer is another nickel, iron, chromium alloy sold by Special Metals Corp. under the trademark Inconel® 600.

The pyrolysis of HFC-245eb to HFO-1234yf and HF is carried out in the absence of catalyst in a substantially empty reactor. By absence of catalyst is meant that no material or treatment is added to the pyrolysis reactor that increases the reaction rate by reducing the activation energy of the pyrolysis process. It is understood that although surfaces that are unavoidably present in any containment vessel, such as a pyrolysis reactor, may have incidental catalytic or anticatalytic effects on the pyrolysis process, the effect makes an insignificant contribution, if any, to the pyrolysis rate. More specifically, absence of catalyst means absence of conventional catalysts in a particulate, pellet, fibrous or supported form that are useful in promoting the elimination of hydrogen fluoride from a hydrofluorocarbon (i.e., dehydrofluorination). Examples of such dehydrofluorination catalysts include: fluorided alumina, aluminum fluoride, chromium oxide, optionally containing other metals, metal oxides or metal halides; chromium fluoride, and activated carbon, optionally containing other metals, metal oxides or metal halides, and others as listed previously herein.

In one embodiment, substantially empty reactors useful for carrying out the dehydrofluorination are tubes comprising the aforementioned materials of construction. Substantially empty reactors include those wherein the flow of gases through the reactor is partially obstructed to cause back-mixing, i.e. turbulence, and thereby promote mixing of gases and good heat transfer. This partial obstruction can be conveniently obtained by placing packing within the interior of the reactor, filling its cross-section or by using perforated baffles. The reactor packing can be particulate or fibrillar, preferably in cartridge disposition for ease of insertion and removal, has an open structure like that of Raschig rings (ceramic or metal pieces of tube that are approximately equal in length and diameter) or other packings with a high free volume, to avoid the accumulation of coke and to minimize pressure drop, and permits the free flow of gas. Preferably the exterior surface of such reactor packing comprises materials identical to those of the reactor inner surface layer; materials that do not catalyze dehydrofluorination of hydrofluorocarbons and are resistant to hydrogen fluoride. The free volume of the reaction zone is at least about 80%, preferably at least about 90%, and more preferably about 95%. The free volume is the volume of the reaction zone minus the volume of the material that makes up the reactor packing.

In one embodiment, the pyrolysis which accomplishes the conversion of HFC-245eb to HFO-1234yf is suitably conducted at a temperature of from about 450° C. to about 900° C. In another embodiment, the pyrolysis is conducted at a temperature of from about 550° C. to about 850° C. In another embodiment, the pyrolysis is conducted at a temperature of from about 600° C. to about 750° C. The pyrolysis temperature is the temperature of the gases inside the reaction zone at about the mid-.

In one embodiment, the residence time of gases in the reaction zone is from about 0.5 to about 60 seconds. In another embodiment, the residence time is from about 2 seconds to about 20 seconds.

In one embodiment, the pyrolysis can be conducted in the presence of one or more unreactive diluent gases, that is diluent gases that do not react under the pyrolysis conditions. Such unreactive diluent gases include the inert gases nitrogen, argon, and helium. Fluorocarbons that are stable under the pyrolysis conditions, for example, trifluoromethane and perfluorocarbons, may also be used as unreactive diluent gases. Of note are processes where the mole ratio of inert gas to HFC-245eb fed to the pyrolysis reactor is from about 5:1 to 1:1. Nitrogen is a preferred inert gas because of its comparatively low cost.

In one embodiment, the pyrolysis reaction is conducted at subatmospheric total pressure. In another embodiment, the pyrolysis reaction can be beneficially run under reduced total pressure (i.e., total pressure less than one atmosphere). In another embodiment, the pyrolysis reaction is carried out at or near atmospheric total pressure.

Liquid Phase Dehydrofluorination

In one embodiment, the dehydrofluorination of HFC-245eb is accomplished using an aqueous alkaline solution. In one embodiment, the reaction is carried out in the presence of a non-aqueous solvent in which the HFC-245eb (CF₃CHFCH₂F) is at least partially miscible. In another embodiment, the reaction is carried out with no non-aqueous solvent. In another embodiment, the reaction is carried out in the presence of a phase transfer catalyst. In yet another embodiment, the reaction is carried out with no phase transfer catalyst.

In one embodiment, the base in the aqueous alkaline solution is selected from the group consisting of hydroxide, oxide, carbonate, or phosphate salts of alkali metals, alkaline earth metals, and mixtures thereof. In one embodiment, bases which may be used include without limitation lithium hydroxide, sodium hydroxide, potassium hydroxide, calcium hydroxide, magnesium oxide, calcium oxide, sodium carbonate, potassium carbonate, sodium phosphate, potassium phosphate, or the like and mixtures thereof.

As used herein, the aqueous alkaline solution is a liquid (whether a solution, dispersion, emulsion, or suspension and the like) that is primarily an aqueous liquid having a pH of over 7. In some embodiments the basic aqueous solution has a pH of over 8. In some embodiments, the basic aqueous solution has a pH of over 10. In some embodiments, the basic aqueous solution has a pH of 10-13. In some embodiments, the basic aqueous solution contains small amounts of organic liquids which may be miscible or immiscible with water. In some embodiments, the liquid medium in the aqueous alkaline solution is at least 90% water. In one embodiment the water is tap water; in other embodiments the water is deionized or distilled water.

The amount of base (in the aqueous alkaline solution) required to convert HFC-245eb to HFO-1234yf is approximately the stoichiometric quantity or about 1 mole of base to one mole of HFC-245eb. In one embodiment, it may desirable (e.g., to increase reaction rate) to employ a ratio of base to HFC-245eb of greater than one. In some embodiments, large excesses of base (in the basic aqueous solution) are to be avoided as further reaction of the desired hydrofluoroolefin may occur. Thus, in some embodiments, it may be necessary to employ an amount of base (in the basic aqueous solution) that is slightly below the stoichiometric amount so as to minimize secondary reactions. Thus, in one embodiment, the molar ratio of base (in the basic aqueous solution) to HFC-245eb is from about 0.75:1 to about 10:1. In another embodiment, the molar ratio of base (in the basic aqueous solution) to HFC-245eb is from about 0.9:1 to about 5:1. In yet another embodiment, the molar ratio of base to HFC-245eb is from about 1:1 to about 4:1.

In certain embodiments, the non-aqueous solvent is selected from the group consisting of alkyl and aryl nitriles, alkyl and aryl ethers, alcohols, amides, ketones, sulfoxides, phosphate esters and mixtures thereof.

In one embodiment, a solid base (e.g., KOH, NaOH, LiOH or mixtures thereof) is dissolved in water, or alternatively, a concentrated solution of a base (e.g., 50% by weight aqueous potassium hydroxide) is diluted to the desired concentration with water. The non-aqueous solvent for the method is then added with agitation under otherwise ambient conditions. In one embodiment, a solvent for the reaction can be a nitrile, ether, alcohol, amide, ketone, sulfoxide, phosphate ester, or mixtures thereof. In another embodiment, the solvent is selected from the group consisting of acetonitrile, propionitrile, butyronitrile, methyl glutaronitrile, adiponitrile, benzonitrile, ethylene carbonate, propylene carbonate, ethanol, methanol, propanol, isopropanol, butanol, methyl ethyl ketone, methyl isoamyl ketone, diisobutyl ketone, anisole, 2-methyltetrahydrofuran, tetrahydrofuran, dioxane, diglyme, triglyme, tetraglyme, N,N-dimethyl formamide, N,N-dimethyl acetamide, N-methyl pyrrolidinone, sulfolane, dimethyl sulfoxide, perfluoro-N-methyl morpholine, perfluorotetrahydrofuran, and mixtures thereof. Preferred solvents include acetonitrile, adiponitrile, 2-methyl tetrahydrofuran, tetrahydrofuran, dioxane, diglyme, and tetraglyme.

As used herein, phase transfer catalyst is intended to mean a substance that facilitates the transfer of ionic compounds into an organic phase from an aqueous phase or from a solid phase. The phase transfer catalyst facilitates the reaction of these dissimilar and incompatible components. While various phase transfer catalysts may function in different ways, their mechanism of action is not determinative of their utility in the reaction provided that the phase transfer catalyst facilitates the dehydrofluorination reaction.

The phase transfer catalyst is selected from the group consisting of crown ethers, onium salts, cryptands, polyalkylene glycols, and mixture thereof.

In one embodiment, the base need not be highly soluble in the solvent. An amount of a phase transfer catalyst may be added to the solvent for the reaction in quantities that improve the solubility of the base therein. In one embodiment, the amount of phase transfer catalyst used will be from about 0.001 to about 10 mole percent based on the total amount of base present. In another embodiment, the amount of phase transfer catalyst used will be from about 0.01 to about 5 mole percent based on the total amount of base present. In yet another embodiment, the amount of phase transfer catalyst used will be from about 0.05 to about 5 mole percent based on the total amount of base present. In one embodiment of the invention, an aqueous or inorganic phase is present as a consequence of the base and an organic phase is present as a result of the HFO-1234yf and the non-aqueous solvent.

In some embodiments, the phase transfer catalyst can be ionic or neutral. In one embodiment, the phase transfer catalyst is selected from the group consisting of crown ethers, onium salts, cryptands and polyalkylene glycols and mixtures and derivatives thereof.

Crown ethers are cyclic molecules in which ether groups are connected by dimethylene linkages; the compounds form a molecular structure that is believed to be capable of “receiving” or holding the alkali metal ion of the hydroxide and to thereby facilitate the reaction. In some embodiments, it is preferred to match certain crown ether phase transfer catalysts with certain bases used in the basic aqueous solutions. In one embodiment, crown ethers include 18-crown-6, is used in combination with potassium hydroxide basic aqueous solution; 15-crown-5, is used in combination with sodium hydroxide basic aqueous solution; 12-crown-4, is used in combination with lithium hydroxide basic aqueous solution. Derivatives of the above crown ethers are also useful, e.g., dibenzo-18-crown-6, dicyclohexano-18-crown-6, and dibenzo-24-crown-8 as well as 12-crown-4. Other polyethers particularly useful in combination with basic aqueous solution made from alkali metal compounds, and especially for lithium, are described in U.S. Pat. No. 4,560,759 the disclosure of which is herein incorporated by reference. Other compounds analogous to the crown ethers and useful for the same purpose are compounds which differ by the replacement of one or more of the oxygen atoms by other kinds of donor atoms, particularly N or S, such as hexamethyl-[14]-4,11-dieneN₄.

In some embodiments, onium salts include quaternary phosphonium salts and quaternary ammonium salts that may be used as the phase transfer catalyst in the process of the present invention; such compounds can be represented by the following formulas II and III:
R¹R²R³R⁴P⁽⁺⁾X′⁽⁻⁾  (II)
R¹R²R³R⁴N⁽⁺⁾X′⁽⁻⁾  (III)
wherein each of R¹, R², R³ and R⁴, which may be the same or different, is an alkyl group, an aryl group or an aralkyl group, and X′ is selected from the group consisting of F, Cl, Br, I, OH, CO₃, HCO₃, SO₄, HSO₄, H₂PO₄, HPO₄ and PO₄. Specific examples of these compounds include tetramethylammonium chloride, tetramethylammonium bromide, benzyltriethylammonium chloride, methyltrioctylammonium chloride (a quaternary ammonium salt sold under the trademark Aliquat™ 336), tetra-n-butylammonium chloride, tetra-n-butylammonium bromide, tetra-n-butylammonium hydrogen sulfate, tetra-n-butylphosphonium chloride, tetraphenylphosphonium bromide, tetraphenylphosphonium chloride, triphenylmethylphosphonium bromide and triphenylmethylphosphonium chloride. In one embodiment, benzyltriethylammonium chloride is used under strongly basic conditions. Other useful compounds within this class of compounds include those exhibiting high temperature stabilities (e.g., up to about 200° C.) including 4-dialkylaminopyridinium salts, tetraphenylarsonium chloride, bis[tris(dimethylamino)phosphine]iminium chloride, and tetratris[tris(dimethylamino)phosphinimino]phosphonium chloride; the latter two compounds are also reported to be stable in the presence of hot, concentrated sodium hydroxide and, therefore, can be particularly useful.

In other embodiments, cryptands are another class of compounds useful in the reaction as phase transfer catalysts. These are three-dimensional polymacrocyclic chelating agents that are formed by joining bridgehead structures with chains that contain properly spaced donor atoms. For example, bicyclic molecules that result from joining nitrogen bridgeheads with chains of (—OCH₂CH₂—) groups as in 2.2.2-cryptand (4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo-(8.8.8)hexacosane; available under the brand name Cryptand™ 222 and the trademark Kryptofix® 222). The donor atoms of the bridges may all be O, N, or S, or the compounds may be mixed donor macrocycles in which the bridge strands contain combinations of such donor atoms.

In some embodiments, polyalkylene glycol ethers are useful as phase transfer catalysts. In some embodiments, the polyalkylene glycol ethers can be represented by the formula:
R⁶O(R⁵O)_tR⁷  (IV)
wherein R⁵ is an alkylene group containing two or more carbon atoms, each of R⁶ and R⁷, which may be the same or different, is a hydrogen atom, an alkyl group, an aryl group or, an aralkyl group, and t is an integer of at least 2. Such compounds include, for example glycols such as diethylene glycol, triethylene glycol, tetraethylene glycol, pentaethylene glycol, hexaethylene glycol, diisopropylene glycol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol and tetramethylene glycol, and monoalkyl ethers such as monomethyl, monoethyl, monopropyl and monobutyl ethers of such glycols, dialkyl ethers such as tetraethylene glycol dimethyl ether and pentaethylene glycol dimethyl ether, phenyl ethers, benzyl ethers, and polyalkylene glycols such as polyethylene glycol (average molecular weight about 300) dimethyl ether, polyethylene glycol (average molecular weight about 300) dibutyl ether, and polyethylene glycol (average molecular weight about 400) dimethyl ether, and ethoxylated furfurylalcohol. Among them, compounds wherein both R—⁶ and R—⁷ are alkyl groups, aryl groups or aralkyl groups are preferred.

Combinations and mixtures of the above described phase transfer catalysts from within one of the groups may also be useful as well as combinations or mixtures of two or more phase transfer catalysts selected from more than one group, for example, crown ethers and oniums, or from more than two of the groups, e.g., quaternary phosphonium salts and quaternary ammonium salts, and crown ethers and polyalkylene glycol ethers.

In one embodiment, the dehydrofluorination is conducted within a temperature range at which the CF₃CHFCH₂F will dehydrofluorinate. In one embodiment, such temperatures can be from about 5° C. to about 150° C. In another embodiment, the reaction is conducted in the range of from about 10° C. to about 110° C. In yet another embodiment, the reaction is carried out in the range of from about 15° C. to about 90° C. The reaction pressure is not critical. The reaction can be conducted at atmospheric pressure, super-atmospheric pressure, or under reduced pressure. In one embodiment, the reaction is carried out at atmospheric pressure.

The dehydrofluorination reactions of this invention may be carried out in either a batch or a continuous mode. In some embodiments, the dehydrofluorination process is carried out in batch mode and in other embodiments, the dehydrofluorination continuous mode. In one embodiment, in the batch mode, the above described components are combined in a suitable vessel for a time sufficient to convert at least a portion of the HFC-245eb to HFO-1234yf and then the HFO-1234yf is recovered from the reaction mixture.

In another embodiment, in a continuous mode of operation, the reaction vessel is charged with the basic aqueous solution, non-aqueous, non-alcoholic solvent, and phase transfer catalyst; the HFC-245eb is then fed to the reactor. The reaction vessel is fitted with a condenser cooled to a temperature sufficient to reflux the HFC-245eb, but permit the HFO-1234yf to exit the reaction vessel and collect in an appropriate vessel such as cold trap.

Products formed by liquid phase dehydrofluorination comprise HF, HFO-1234yf, and, if HFC-254eb is present in the feed mixture, HFO-1243zf. In one embodiment, the HFO-1234yf is typically separated from the lower boiling products and higher boiling products by conventional means (e.g., distillation).

Dehydrofluorination of HFC-245eb may also produce HFO-1234ze (Z- and/or E-isomers) as an additional compound, under the same conditions, as described herein, used to produce HFO-1234yf from HFC-245eb. Higher temperatures have been found to produce higher levels of HFO-1234ze. This reaction is also shown in FIG. 1.

Hydrogenation of HFO-1234ze may produce HFC-254fb as an additional compound, under typical conditions for hydrogenation, as described in International Patent Application Publication WO2008/030440 A2. Generally, HFO-1234ze is added with hydrogen to a reaction vessel containing a hydrogenation catalyst, such as palladium or supported palladium, wherein the support may be alumina, aluminum fluoride, or carbon, as well as other hydrogenation catalysts. The reaction may be carried out at temperatures from about 50° C. to about 300° C. with a contact time of about 5 to about 100 seconds. The molar ratio of hydrogen to HFO-1234ze may be anywhere from about 1.5:1 to about 25:1. This reaction is shown in FIG. 1.

Hydrogenation of the product HFO-1234yf may produce HFC-254eb as an additional compound, as shown in FIG. 1, under the same conditions as described above for the hydrogenation of HFO-1234ze to HFC-254fb.

Dehydrofluorination of the HFC-254eb or HFC-254fb may produce HFO-1243zf as an additional compound, as shown in FIG. 1, under the same conditions as described herein for the dehydrofluorination of HFC-245eb to produce HFO-1234yf.

EXAMPLES

General Procedure for Product Analysis

The following general procedure is illustrative of the method used for analyzing the products of fluorination reactions. Part of the total reactor effluent was sampled on-line for organic product analysis using a gas chromatograph equipped with a mass selective detector (GC/MS). The gas chromatography utilized a 20 ft. (6.1 m) long×⅛ in. (0.32 cm) diameter tube containing a perfluorinated polyether sold under the trademark Krytox® by E.I. du Pont de Nemours and Company (“DuPont” of Wilmington, Del.) on an inert carbon support. The helium flow was 30 mL/min (5.0×10⁻⁷ m³/sec). Gas chromatographic conditions were 60° C. for an initial hold period of three minutes followed by temperature programming to 200° C. at a rate of 6° C./minute.

Legend

• 23 is CHF₃
• 1132a is CH₂═CF₂
• 1225zc is CF₃CH═CF₂
• 1234yf is CF₃CF═CH₂
• E- and Z-1234ze are E- and Z—CF₃CH═CHF
• 245eb is CF₃CHFCH₂F
  Preparation of Fluorided Alumina Catalyst

A Hastelloy® tube (1″ OD×0.854 ID×10″L) was filled with 25 cc (16.68 grams) gamma-alumina ground to 12-20 mesh. The packed portion of the reactor was heated by a 5.0″×1″ ceramic band heater clamped to the outside of the reactor. A thermocouple, positioned between the reactor wall and the heater, measured the reactor temperature. The catalyst was dried by heating at 200° C. overnight under a nitrogen flow of 50 sccm (8.33×10⁻⁷ m³/s). The nitrogen flow was then reduced to 5 sccm (8.33×10⁻⁸ m³/s) and a flow of 20 sccm (3.33×10-7 m³/s) CFC-12 (CF₂Cl₂) started and maintained for 60 minutes. The temperature was raised to 325° C. and held at this temperature for a further 60 minutes. The CFC-12 flow stopped and the reactor temperature raised to 400° C. under a flow of 50 sccm (8.33×10⁻⁷ m³/s) of nitrogen and held at this temperature for an additional 60 minutes. The reactor was then brought to the desired operating temperature.

Example 1

Vapor Phase Dehydrofluorination of HFC-245eb to HFO-1234yf with Fluorided Alumina Catalyst

To the reactor containing the fluorided alumina catalyst prepared as above was fed a vapor of HFC-245eb and nitrogen at various reactor temperatures. The nitrogen to HFC-245eb ratio was 0.67:1 and the contact time was 36 seconds for the first four analyses. For the fifth analysis, the nitrogen to HFC-245eb ratio was 1:1 and the contact time was 90 seconds. The product leaving the reactor was analyzed by GC/MS and the results in mole % are summarized in Table 2.

TABLE 2
Reactor T, ° C.	1234yf	E-1234ze	Z-1234ze	245eb
200	ND	ND	ND	99.9
300	14.3	3.6	0.8	81.2
350	28.2	9.5	2.3	60.0
400	45.4	18.9	4.4	31.3
400	52.0	22.0	5.4	20.4
ND = Not detected

Example 2

Pyrolysis of HFC-245eb

The reactor was a 9.5 inch (24.1 cm) long×0.50 inch (1.3 cm) outer diameter×0.35 inch (0.89 cm) inner diameter tubing with a wall thickness of 0.15 inch (3.8 mm) containing an internal gold lining. The thickness of the gold lining was 0.03 inch (0.08 cm). The reactor was heated with a ceramic band heater 5.7 inch long (14.5 cm)×1 inch outer diameter (2.5 cm) clamped to the outside. A dual control thermocouple, centered in the middle of the band heater between the outside of the reactor and the inside of the band heater was used to control and measure reactor temperature. To the reactor heated to various operating temperatures was fed 5 sccm (8.33×10⁻⁸ m³/s) nitrogen and 2.37 mL per hour of liquid HFC-245eb that was vaporized before entering the reactor. The contact time was 60 seconds for all runs. The reactor effluent was analyzed by an in-line GC/MS. The product analysis in mole %, at various operating temperatures is summarized in Table 3.

TABLE 3
Temp° C.	Unknown	23	1132a	1234yf	E-1234ze	1225ye	Z-1234ze	245eb
600	0.5	0.8	0.1	3.1	1.0	ND	0.2	94.3
650	1.9	4.7	1.0	5.9	2.3	0.3	0.8	83.1
700	4.3	17.4	5.1	16.7	8.5	1.8	3.7	42.5
750	7.7	24.6	7.9	28.0	14.8	3.4	6.6	6.9
ND = non-detectable

Example 3

Liquid Phase Dehydrofluorination of HFC-245eb to HFC-1234yf

A three neck, 2 liter flask was equipped with a water ice condenser, thermocouple, and over-head stirrer. The effluent of the condenser was passed through a CaSO₄ drier and then through activated molecular sieves and a stainless steel trap with dip tube immersed in dry ice/acetone. An oil bubbler made of perfluorinated polyether sold under the trademark Krytox® by DuPont (Wilmington, Del.) the exit of the stainless steel trap prevented contamination of the trapped product by moisture.

The flask was charged with water (736 mL), tetrahydrofuran (200 mL), KOH pellets (180 grams, 3.21 mol), and methyltrioctylammonium chloride, a quaternary ammonium salt sold under the trademark Aliquat™ 336 (3.13 grams, 7.74×10⁻³ mol) that functions as a phase transfer catalyst. While vigorously stirring, CF₃CHFCH₂F (HFC-245eb) was added at a rate of about 100 sccm. The pH of the basic aqueous solution was about 13. Two phases were present in the flask. About 247 grams of crude product was collected containing 96.1% 1234yf, 0.5% Z-1234ze, 0.1% E-1234ze and 2.9% unreacted HFC-245eb. Very little exotherm was observed while feeding the HFC-245eb.

Claims

1. A composition comprising hfo-1234yf, hfo-1234ze, HFC-245eb, and HFC-245cb; wherein said composition contains less than about 1 weight percent total of hfo-1234ze, HFC-245eb, and HFC-245cb.

2. The composition of claim 1 wherein the composition comprises E-hfo-1234ze and Z-hfo-1234ze.

3. The composition of claim 1, further comprising 3,3,3-trifluoropropyne.

4. A working fluid for carrying heat between a heat sink and heat source, the working fluid comprising hfo-1234yf, hfo-1234ze, HFC-245eb, and HFC-245cb; wherein said working fluid contains greater than zero and less than about 1 weight percent total of hfo-1234ze, HFC-245eb, and HFC-245cb.

5. The working fluid of claim 4, further comprising 3,3,3-trifluoropropyne.

6. A heat transfer composition comprising hfo-1234yf, hfo-1234ze, HFC-245eb, and HFC-245cb; wherein said composition contains greater than zero and less than about 1 weight percent total of hfo-1234ze, HFC-245eb, and HFC-245cb.

7. The heat transfer composition of claim 6, further comprising 3,3,3-trifluoropropyne.

8. A heat transfer method comprising providing and using a composition comprising hfo-1234yf, hfo-1234ze, HFC-245eb, and HFC-245cb with greater than zero and less than about 1 weight percent total of hfo-1234ze, HFC-245eb, and HFC-245cb, as a working fluid to carry heat from a heat source to a heat sink.

9. A heat transfer method comprising providing and using a heat transfer composition comprising hfo-1234yf, hfo-1234ze, HFC-245eb, and HFC-245cb, wherein said composition contains greater than zero and less than about 1 weight percent total of hfo-1234ze, HFC-245eb, and HFC-245cb, and changing the phase of the heat transfer composition to and from a gas or liquid and to and from a liquid to a gas to transfer heat.

10. A heat transfer system comprising a composition comprising hfo-1234yf, hfo-1234ze, HFC-245eb, and HFC-245cb wherein said composition contains greater than zero and less than about 1 weight percent total of hfo-1234ze, HFC-245eb, and HFC-245cb.

11. The system of claim 10, comprising an air conditioner, or a heat pump, or a refrigerator, or a water chiller, or a flooded evaporator chiller or a direct expansion chiller, or a mobile refrigerator, or a mobile refrigeration apparatus, or a mobile air conditioning apparatus or a mobile heating apparatus, or a stationary heat transfer system.

12. A heat transfer system comprising a heat source, a heat sink, and a working fluid to carry heat from the heat source to the heat sink, wherein said working fluid comprises hfo-1234yf, hfo-1234ze, HFC-245eb, and HFC-245cb; and wherein said working fluid contains greater than zero and less than about 1 weight percent total of hfo-1234ze, HFC-245eb, and HFC-245cb.

13. The system of claim 12, wherein the working fluid further comprises 3,3,3-trifluoropropyne.

14. In combination, a stationary heat transfer system and the composition of claim 1.

15. In combination, a mobile refrigeration apparatus, mobile air conditioning apparatus or mobile heating apparatus and the composition of claim 1.

16. Refrigeration equipment containing a composition comprising hfo-1234yf, hfo-1234ze, HFC-245eb, and HFC-245cb and greater than zero, and less than about 1 weight percent total of hfo-1234ze, HFC-245eb, and HFC-245cb hfo-1234ze, HFC-245eb, and HFC-245cb.

17. The equipment of claim 16, wherein the composition further comprises 3,3,3-trifluoropropyne.