Compositions comprising 2,3,3,3-tetrafluoropropene

Abstract

Compositions comprising HFO-1234yf and at least one additional compound selected from the group consisting of HCFO-1223xd, HCFC-233ab, HFO-1234yf, HCFC-244db, HFC-245fa, HFC-245cb, and 253fb are described. Compositions containing HFO-1234yf are useful, among other uses, as heat transfer compounds for use in refrigeration, air conditioning, and heat pump systems.

Description

Compositions comprising 2,3,3,3-tetrafluoropropene Background 1. Field of the invention. This description pertains to compositions that may be useful as heat transfer compositions, aerosol propellants, foaming agents, blowing agents, solvents, cleaning agents, carrier fluids, displacement drying agents, abrasive polishing agents, polymerization media, blowing agents for polyolefins and polyurethane, gaseous dielectrics, extinguishing agents, and fire extinguishing agents in liquid or gaseous form. In particular, this description pertains to compositions that may be useful as heat transfer compositions, such as 2,3,3,3-tetrafluoropropene (HFO-1234yf or 1234yf) or compositions comprising 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb). 2. Description of the related technique New environmental regulations have led to the need for new compositions for use in refrigeration, heat pumps, and air conditioning equipment. Compounds with low global warming potential are of particular interest. Document US 2007 / 197842 A1 refers to a method for producing fluorinated organic compounds and discloses intermediate compositions comprising CF3CFClCH3 (244bb). Summary of the invention The applicants have found that, when preparing such new low global warming potential compounds, such as 1234yf, certain additional compounds are present in small quantities. Compositions comprising HCFC-243db, HCFO-1233xf, and / or HCFC-244db are useful in processes for manufacturing HFO-1234yf. Therefore, compositions comprising 1234yf may contain some amount of HCFC-243db, HCFO-1233xf, and / or HCFC-244db, in addition to other compounds. According to the present invention, a composition comprising HCFC-244bb and at least one additional compound selected from the group consisting of HCFC-244b, HCFC-243b, HCFC-244b, and HFC-245fb is provided. The composition may contain from a weight percent greater than zero up to 99 percent by weight of HCFC-244bb. Furthermore, according to the present invention, a composition as described in claims 2 to 7 and a use as described in claim 8 are provided. Brief description of the drawings Figure 1 is a schematic drawing showing a reaction for producing HFO-1234yf from 243db. Detailed description of preferred embodiments HFO-1234yf has been suggested for use as a refrigerant, heat transfer fluid, aerosol propellant, foam blowing agent, and other applications. It has also been advantageously found that HFO-1234yf has a low global warming potential (GWP), as reported by V.C. Papadimitriou et al. in Physical Chemistry and Chemical Physics, 2007, Volume 9, Pages 1-13. Therefore, HFO-1234yf is a good candidate to replace higher-GWP saturated HFC refrigerants. According to the invention, the present disclosure provides a composition comprising HCFC-244bb and at least one additional compound selected from the group consisting of HCFO-1223xd, HCFC-253fb, HCFC-233ab, HCFC-244db, and HFC-245fa. In one embodiment, the total amount of additional compound(s) in the composition comprising HCFC-244bb ranges from greater than zero percent by weight to 99 percent by weight. In another embodiment, the total amount of additional compounds ranges from 1 percent by weight to 80 percent by weight. In another embodiment, the total amount of additional compounds ranges from 1 percent by weight to 50 percent by weight. In another embodiment, the total amount of additional compounds ranges from 1 percent by weight to 30 percent by weight. In another embodiment, the total amount of additional compounds ranges from 1 percent by weight to 10 percent by weight. In some embodiments, certain precursor compounds of HCFC-244bb contain impurities that appear in HCFC-244bb. In other embodiments, additional compounds are formed by reaction with these precursor impurities. In still other embodiments, the reaction conditions under which HCFC-244bb is produced also generate byproducts that subsequently appear in HCFC-243db compositions, meaning that alternative reaction pathways may exist that produce additional compounds depending on the specific conditions under which HCFC-244bb is produced. The compositions described in the present invention comprising HFO-1234yf are useful as low global warming potential (GWP) heat transfer compositions, aerosol propellants, foaming agents, blowing agents, solvents, cleaning agents, carrier fluids, displacement drying agents, polishing abrasives, polymerization media, blowing agents for polyolefins and polyurethanes, gaseous dielectrics, extinguishing agents, and fire extinguishing agents in liquid or gaseous form. The described compositions can act as a working fluid used to transfer heat from a heat source to a heat sink. Such heat transfer compositions can also be useful as a coolant in a cycle where the fluid undergoes a phase change; that is, from a liquid to a gas, and vice versa. Examples of heat transfer systems include, but are not limited to, air conditioners, freezers, refrigerators, heat pumps, water chillers, flooded evaporator chillers, direct expansion chillers, chamber refrigerators, heat pumps, mobile refrigerators, mobile air conditioning units, and combinations thereof. As used in the present invention, mobile refrigeration unit, mobile air conditioning unit, or mobile heating unit refers to any refrigeration, air conditioning, or heating unit incorporated into a road, rail, sea, or air transport unit. Furthermore, mobile refrigeration or air conditioning units include those units that are independent of any mobile support and are known as "intermodal" systems. Such intermodal systems include "containers" (combined sea / land transport) as well as "swap boxes" (combined road / rail transport). As used in the present invention, stationary heat transfer systems are systems associated with or attached to buildings of any variety. These stationary applications may be stationary heat pumps and air conditioning systems (including, but not limited to, chillers, high-temperature heat pumps, residential, commercial, or industrial air conditioning systems, and including window, ducted, ductless, terminal package chillers, and those outdoor units connected to the building, such as rooftop systems).In stationary refrigeration applications, the described compositions can be useful in equipment including commercial, industrial, or residential refrigerators and freezers, ice machines, self-contained refrigerators and freezers, flooded evaporator chillers, direct expansion chillers, cold storage refrigerators and freezers, and cold rooms and combination systems. In some embodiments, the described compositions can be used in supermarket refrigeration systems. Table 1 defines the compounds that make up the described compositions. Table 1 HCFC-243db, HCFO-1233xf, and HCFC-244bb are available from specialized chemical manufacturers, including SynQuest Laboratories, Inc. (Alachua, FL, USA) or can be prepared as described in the present invention. For example, HCFC-243db, HCFO-1233xf, and HCFC-244bb can be prepared by noncatalytic chlorination of HFO-1243zf, as described in International Patent Application Publication Number WO2008 / 054782, published on May 8, 2008. HCFO-1233xf and HCFC-244bb can also be prepared by catalytic fluorination of 243db, as described in International Patent Application Publication Number WO2008 / 054781, published on May 8, 2008. The additional compounds present in each described composition will depend on the manufacturing method. In some embodiments, certain precursor compounds for HCFC-243db, HCFO-1233xf, or HCFC-244bb contain impurities that subsequently appear as additional compounds in the described compositions. In other embodiments, these precursor compounds may themselves react during the formation of 243db to form additional compounds that subsequently appear in the HCFC-243db compositions. In still other embodiments, the reaction conditions under which HCFC-243db, HCFO-1233xf, or HCFC-244bb are produced also produce byproducts, meaning that adventitious reaction pathways may occur simultaneously to produce compounds other than HCFC-243db, HCFO-1233xf, or HCFC-244bb, and the amount and identity of these additional compounds will depend on the particular conditions under which HCFC-243db, HCFO-1233xf, or HCFC-244bb are produced. HFO-1234yf can be produced in a single step from HCFC-243db, or the reaction sequence can be carried out in a stepwise manner. HCFO-1233xf can be produced from HCFC-243db and then directly converted to HFO-1234yf. HCFC-244bb can be produced from HCFC-243db and then converted to HFO-1234yf. Fluorochlorination of HFO-1243zf HFO-1243zf can be used to produce HCFC-243db, HCFO-1233xf, HCFC-244db, and / or HFO-1234yf by fluorochlorination. HFO-1243zf is commercially available from E.I. DuPont de Nemours and Company (Wilmington, DE, USA). The fluorochlorination reaction can be carried out in the liquid or vapor phase. For liquid-phase reactions, HFO-1243zf can be reacted with HF and Cl2 in a liquid-phase reactor operating in batch, semi-batch, semi-continuous, or continuous mode. In batch mode, HFO-1243zf, Cl2, and HF are combined in an autoclave or other suitable reaction vessel and heated to the desired temperature. This reaction can be carried out in semi-batch mode by feeding Cl₂ to a liquid-phase reactor containing HF and HFO-1243zf, or by feeding HFO-1243zf and Cl₂ to a liquid-phase reactor containing HF, or by feeding Cl₂ to a mixture containing HF and the reaction products formed by initially heating HFO-1243zf and HF. HF and Cl₂ can be fed to a liquid-phase reactor containing a mixture of HFO-1243zf and the reaction products formed by the reaction of HF, Cl₂, and HFO-1243zf. In the liquid-phase process, HF, Cl₂, and HFO-1243zf can be fed concurrently in the desired stoichiometric ratio to the reactor containing a mixture of HF and the reaction products formed by the reaction of HF, Cl₂, and HFO-1243zf. Suitable temperatures for the reaction of HF and Cl2 with HFO-1243zf in the liquid-phase reactor are 80°C to 180°C or 100°C to 150°C. Higher temperatures typically result in greater conversion of HFO-1243zf. A suitable molar ratio of HF to the total amount of HFO-1243zf fed to the liquid-phase reactor is at least stoichiometric, or from 5:1 to 100:1. The molar ratio of HF to HFO-1243zf can be from 8:1 to 50:1. A suitable molar ratio of Cl2 to the total amount of HFO-1243zf fed to the liquid-phase reactor is from 1:1 to 2:1. The reactor pressure in the liquid-phase process is not critical, and in batch reactions, it is usually the autogenous pressure of the system at the reaction temperature. The system pressure increases as hydrogen chloride is formed by the substitution of hydrogen substituents with chlorine, and by the substitution of chlorine substituents with fluorine in the starting materials and intermediate reaction products. In a continuous process, it is possible to set the reactor pressure so that the lower-boiling reaction products, such as HCl, HFO-1234yf (CF3CF=CH2), E / Z-1234ze (E / Z-CF3CH=CHF), and HFC-245cb (CF3CF2CH3), are vented from the reactor, optionally through a packed column or condenser. In this way, the higher-boiling intermediate compounds remain in the reactor, and the volatile products are removed. Typical reactor pressures range from 239 kPa (20 psig) to 6,994 kPa (1,000 psig). When the reaction is carried out using a liquid-phase process, the catalysts that can be used include carbon, AlF3, BF3, FeCl3-aFa (where a = 0 to 3), FeX3 supported on carbon, SbCl3-aFa, AsF3, MCl5-bFb (where b = 0 to 5 and M = Sb, Nb, Ta or Mo), and M'Cl4-cFc (where c = 0 to 4, and M' = Sn, Ti, Zr or Hf). The catalysts for the liquid-phase process can also be MCl5-bFb (where b = 0 to 5 and M = Sb, Nb or Ta). The reaction of HF and Cl₂ with HFO-1243zf can be carried out in the vapor phase. Typically, a heated reactor is used. Several reactor configurations are possible, including horizontal or vertical orientation, as well as different reaction sequences of HFO-1243zf with HF and Cl₂. The HFO-1243zf can be initially vaporized and fed to the reactor as a gas. HFO-1243zf can be contacted with HF, optionally in the presence of Cl2, in a pre-reactor prior to the reaction in the vapor-phase reactor. The pre-reactor can be empty, or the reactor can be filled with a suitable packing material such as commercially available nickel-copper alloys from Special Metals Corp. (New Hartford, New York) under the trademark Monel® (hereinafter "Monel®"), commercially available nickel-based alloys from Haynes International (Kokomo, Indiana) under the trademark Hastelloy® (hereinafter "Hastelloy®"), or other nickel alloy chips or wool, or other material inert to HCl and HF that allows for efficient mixing of HFO-1243zf and HF vapor. Suitable pre-reactor temperatures in one embodiment are 80°C to 250°C or 100°C to 200°C. Temperatures above approximately 100°C result in some conversion of HFO-1243zf to compounds with a higher degree of fluorination. Higher temperatures result in greater conversion of the HFO-1243zf entering the reactor and a higher degree of fluorination in the converted compounds. Under these conditions, for example, a mixture of HF, Cl2, and HFO-1243zf is converted into a mixture containing predominantly HCFC-243db and HCFC-244db (CF3CHClCH2F). The degree of fluorination reflects the number of fluorine substituents that replace chlorine substituents in HFO-1243zf and its chlorinated products. For example, HCFC-253fb represents a higher degree of fluorination than HCC-250fb, and HFO-1243zf represents a higher degree of fluorination than HCO-1240zf. The molar ratio of HF to the total amount of HFO-1243zf in the pre-reactor can be either the stoichiometric ratio of HF to the total amount of HFO-1243zf at 50:1 or twice the stoichiometric ratio of HF to the total amount of HFO-1243zf at 30:1. The molar ratio of HF to the total amount of HFO-1243zf is present in the pre-reactor, and no additional HF can be added to the vapor-phase reaction zone. HFO-1243zf can be contacted with Cl2 in a pre-reactor, optionally in the presence of HF, before the reaction in the vapor phase reactor. Suitable temperatures for the pre-reactor can range from 80°C to 250°C, preferably from 100°C to 200°C. Under these conditions, at least a portion of HFO-1243zf is converted to HCFC-243db. Higher temperatures typically result in a greater degree of halogenation of HFO-1243zf. The degree of halogenation reflects the total number of halogen substituents (chlorine plus fluorine) in a halopropane and / or halopropene product. For example, HFO-1234yf has a higher degree of halogenation (i.e., 4) than HFO-1243zf (i.e., 3). The molar ratio of Cl2 to the total amount of HFO-1243zf can be from 0.5:1 to 2:1 or from 1.1:1 to 1:1. HFO-1243zf can be vaporized, optionally in the presence of HF, and fed to a pre-reactor or a vapor-phase reactor together with HF and Cl2. Suitable temperatures for the vapor-phase reaction range from 120°C to 500°C. Temperatures from 250°C to 350°C favor the formation of HFO-1234yf and HFC-245cb. Temperatures from 350°C to 450°C favor the formation of HFO-1234ze, HFC-245fa, and HCFO-1233zd. At temperatures from 250°C to 450°C, some HCFO-1233xf is also produced. Higher temperatures result in greater conversion of HFO-1243zf and higher degrees of fluorination and halogenation in the converted compounds. Suitable reactor pressures for the vapor-phase reactor can range from 1 to 30 atmospheres. A pressure of 15 to 25 atmospheres can be advantageously employed to facilitate the separation of HCl from the other reaction products, and the appropriate reaction time can vary from 1 to 120 seconds, preferably from 5 to 60 seconds. The molar ratio of HF to the total amount of HFO-1243zf for the vapor-phase reaction can be from the stoichiometric ratio of HF to the total amount of HFO-1243zf to 50:1 or from 10:1 to 30:1. A catalyst can be used in the reaction zone for the vapor-phase reaction of HF and Cl2 with HFO-1243zf. Chlorofluorination catalysts that can be used in the vapor-phase reaction include carbon; graphite; alumina; fluorinated alumina; aluminum fluoride; alumina supported on carbon; aluminum fluoride supported on carbon; fluorinated alumina supported on carbon; magnesium fluoride supported on aluminum fluoride; metals (including elemental metals, metal oxides, metal halides, and / or other metal salts); metals supported on aluminum fluoride; metals supported on fluorinated alumina; metals supported on alumina; and metals supported on carbon; and mixtures of metals. Suitable metals for use as catalysts (optionally supported on alumina, aluminum fluoride, fluorinated alumina, or carbon) include chromium, iron, cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium, platinum, manganese, rhenium, scandium, yttrium, lanthanum, titanium, zirconium, and hafnium, copper, silver, gold, zinc, and / or metals with an atomic number from 58 to 71 (i.e., the lanthanide metals). When used on a support, the total metal content of the catalyst can be 0.1 to 20 percent by weight based on the total weight of the catalyst or 0.1 to 10 percent by weight based on the total weight of the catalyst. Chlorofluorination catalysts suitable for vapor-phase reactions include catalysts containing chromium, including chromium(III) oxide (Cr2O3); Cr2O3 with other metals such as magnesium halides or zinc halides supported on Cr2O3; chromium(III) halides supported on carbon; mixtures of chromium and magnesium (including elemental metals, metal oxides, metal halides, and / or other metal salts) optionally supported on graphite; and mixtures of chromium and other metals (including elemental metals, metal oxides, metal halides, and / or other metal salts) optionally supported on graphite, alumina, or aluminum halides such as aluminum fluoride. Chromium-containing catalysts are well known in the art. They can be prepared either by precipitation methods or by impregnation methods such as those generally described by Satterfield on pages 87-112 in Heterogeneous Catalysis in Industrial Practice, 2nd edition (McGraw-Hill, New York, 1991). Of particular note are chlorofluorination catalysts comprising at least one chromium-containing component selected from the group consisting of crystalline alpha-chromium oxide where 0.05 atomic percent to 6 atomic percent of the chromium atoms in the alpha-chromium oxide lattice are replaced by trivalent cobalt atoms, and crystalline alpha-chromium oxide where 0.05 atomic percent to 6 atomic percent of the chromium atoms in the alpha-chromium oxide lattice are replaced by trivalent cobalt atoms that have been treated with a fluorinating agent.These catalysts, including their preparation, have been described in United States Patent Application Publication Number US2005 / 0228202. Optionally, the catalysts containing the metals described above can be pretreated with HF. This pretreatment can be carried out, for example, by placing the metal-containing catalyst in a suitable container and then passing HF over it. This container can be the reactor used to perform the chlorofluorination reaction. The pretreatment time can range from 15 to 300 minutes, and the pretreatment temperature can range from 200°C to 450°C. Halopropane byproducts that can form in chlorofluorination reactions with higher degrees of halogenation and / or fluorination than pentafluoropropanes include CF3CCl2CF3 (CFC-216aa), CF3CClFCClF2 (CFC-216ba), CF3CClFCF3 (CFC-217ba), CF3CF2CClF2 (CFC-217ca), CF3CHFCF3 (HFC-227ea), CF3CF2CHF2 (HFC-227ca), CF3CClFCHF2 (HCFC-226ba), CF3CF2CHClF (HCFC-226ca), CF3CHClCF3 (HCFC-226da), CF3CCl2CHF2 (HCFC-225aa), CF3CClFCHClF (HCFC-225ba). CF3CF2CHCl2 (HCFC-225ca), CF3CCl2CClF2 (CFC-215aa), CF3CClFCCl2F (CFC-215bb), CF3CCl2CCl2F (HCFC-214ab), CF3CCl2CHClF (HCFC-224aa), and CF3CClFCHCl2 (HCFC-224ba) . Halopropene byproducts that can be formed in chlorofluorination reactions with a higher degree of halogenation than tetrafluoropropenes include CF3CCl=CHCl (HCFO-1223xd) . In cases where the product mixture produced by the procedures described herein comprises (i) product compounds HFC-245cb, HFC-245fa, HFO-1234yf, HFO-1234ze, HCFO-1233zd and HCFO-1233xf, (ii) HF, HCl, and Cl2, (iii) high-boiling by-products such as CF3CHClCH2Cl (HCFC-243db), CF3CHClCH2F (HCFC-244bb) and (iv) chlorinated by-products such as C3HCl3F4, C3HCl2F3, C3HClF6, C3Cl3F5, and C3Cl2F6, separation processes such as distillation may be employed to recover the product compounds from such product mixture. Fluorination of HCFC-243db HCFC-243db can be used to prepare HCFC-HCFO-1233xf, HCFC-244db, and / or HFO-1234yf by fluorination. These reactions are shown in Figure 1. The fluorination reaction can be carried out in the liquid or vapor phase. For the liquid-phase reactions described herein, the reaction of HCFC-243db with HF can be performed in a liquid-phase reactor operating in batch, semi-batch, semi-continuous, or continuous mode. In batch mode, at startup, HCFC-243db and HF are combined in an autoclave or other suitable reaction vessel and heated to the desired temperature. This reaction can be carried out in semi-batch mode by feeding HF to a liquid-phase reactor containing HCFC-243db, or by feeding HCFC-243db to a liquid-phase reactor containing HF, or by feeding HF to a mixture containing HF and reaction products formed by initially heating HCFC-243db and HF. Alternatively, HF can be fed to a liquid-phase reactor containing a mixture of HCFC-243db and reaction products formed by the reaction of HF and HCFC-243db. In another alternative to the liquid-phase process, HF and HCFC-243db can be fed concurrently in the desired stoichiometric ratio to the reactor containing a mixture of HF and reaction products formed by the reaction of HF and HCFC-243db. Suitable temperatures for the reaction of HF with HCFC-243db in the liquid-phase reactor are 80°C to 180°C or 100°C to 150°C. Higher temperatures usually result in greater conversion of HCFC-243db. A suitable molar ratio of HF to HCFC-243db fed to the liquid-phase reactor is at least stoichiometric, or from 5:1 to 100:1. The molar ratio of HF to HCFC-243db can also be from 8:1 to 50:1. The reactor pressure in the liquid-phase process is not critical and in batch reactions is usually the autogenous pressure of the system at the reaction temperature. The system pressure increases as hydrogen chloride is formed by the substitution of chlorine substituents with fluorine in the HCFC-243db and in the intermediate reaction products. In a continuous process, it is possible to adjust the reactor pressure so that lower-boiling reaction products, such as HCl, CF3CF=CH2, and E / Z-CF3CH=CHF, are vented from the reactor, optionally through a packed column or condenser. In this way, the intermediate products with higher boiling points remain in the reactor and the volatile products are eliminated.Typical reactor pressures are from 239 kPa (20 psig) to 6,994 kPa (1,000 psig). When the reaction is carried out using a liquid-phase process, the catalysts that can be used include carbon, AlF3, BF3, FeCl3-aFa (where a = 0 to 3), FeX3 supported on carbon, SbCl3-aFa, AsF3, MCl5-bFb (where b = 0 to 5 and M = Sb, Nb, Ta or Mo) and M'Cl4-cFc (where c = 0 to 4, and M' = Sn, Ti, Zr or Hf). The catalysts for the liquid-phase process can be MCl5-bFb (where b = 0 to 5 and M = Sb, Nb or Ta). The reaction of HF with HCFC-243db can be carried out in the vapor phase. Typically, a heated reactor is used. Several reactor configurations are possible, including horizontal or vertical orientation, as well as different reaction sequences of the starting materials with HF. The HCFC-243db can be initially vaporized and fed to the reactor as a gas. Alternatively, HCFC-243db can be contacted with HF in a pre-reactor prior to the reaction in the vapor-phase reactor. The pre-reactor can be empty, but preferably is filled with a suitable packing material such as commercially available nickel-copper alloys from Special Metals Corp. (New Hartford, New York) under the trade name Monel®, nickel-based alloys such as Hastelloy®, or other nickel alloy chips or wool, or other material inert to HCl and HF that allows for efficient mixing of HCFC-243db and HF vapor. Suitable temperatures for the pre-reactor are 80°C to 250°C or 100°C to 200°C. Temperatures above 100°C result in some conversion of HCFC-243db to compounds with a higher degree of fluorination. Higher temperatures result in greater conversion of the HCFC-243db entering the reactor and a higher degree of fluorination in the converted compounds. Under these conditions, for example, a mixture of HF and HCFC-243db is converted into a mixture containing predominantly HF, HCl, HCFC-243db, HCFC-244db (CF3CHClCH2F), and HCFO-1233xf. The degree of fluorination reflects the number of fluorine substituents that replace chlorine substituents in HCFC-243db and its fluorinated products. For example, HFO-1234yf represents a higher degree of fluorination than HCFO-1233xf. The molar ratio of HF to the total amount of HCFC-243db in the pre-reactor can be either the stoichiometric ratio of HF to the total amount of HCFC-243db at 50:1 or twice the stoichiometric ratio of HF to the total amount of HCFC-243db at 30:1. Alternatively, the molar ratio of HF to the amount of HCFC-243db is already present in the pre-reactor, and no additional HF can be added to the vapor-phase reaction zone. The HCFC-243db and HF can be vaporized and fed to a pre-reactor or a vapor-phase reactor. Suitable temperatures for the vapor-phase reaction range from 120°C to 500°C. Temperatures in the range of 300°C to 350°C favor the formation of HFO-1234yf, HFC-245cb, and HCFO-1233xf. Temperatures in the range of 350°C to 450°C favor the additional formation of HFO-1234ze, HFC-245fa, and HCFO-1233zd. Higher temperatures result in greater conversion of HCFC-243db and higher degrees of fluorination in the converted products. Reactor temperatures from 150°C to 275°C favor the formation of HCFO-1233xf as the main product. Suitable reactor pressures for the vapor-phase reactor can range from 1 to 30 atmospheres. A pressure of 15 to 25 atmospheres can be advantageously employed to facilitate the separation of HCl from the other reaction products, and the appropriate reaction time can vary from 1 to 120 seconds, preferably from 5 to 60 seconds. The molar ratio of HF to HCFC-243db for the vapor-phase reaction can be from the stoichiometric ratio of HF to HCFC-243db to 50:1 or from 10:1 to 30:1. A catalyst can be used in the reaction zone for the vapor-phase reaction of HF with HCFC-243db. Fluorination catalysts that can be used in the vapor-phase reaction include carbon; graphite; alumina; fluorinated alumina; aluminum fluoride; alumina supported on carbon; aluminum fluoride supported on carbon; fluorinated alumina supported on carbon; magnesium fluoride supported on aluminum fluoride; metals (including elemental metals, metal oxides, metal halides and / or other metal salts); metals supported on aluminum fluoride; metals supported on fluorinated alumina; metals supported on alumina; and metals supported on carbon; and mixtures of metals. Suitable metals for use as catalysts (optionally supported on alumina, aluminum fluoride, fluorinated alumina, or carbon) include chromium, iron, cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium, platinum, manganese, rhenium, scandium, yttrium, lanthanum, titanium, zirconium, and hafnium, copper, silver, gold, zinc, and / or metals with an atomic number from 58 to 71 (i.e., the lanthanide metals). When used on a support, the total metal content of the catalyst can be 0.1 to 20 percent by weight based on the total weight of the catalyst or 0.1 to 10 percent by weight based on the total weight of the catalyst. Typical fluorination catalysts for the vapor-phase reactions described in this document include chromium-containing catalysts, including chromium(III) oxide (Cr2O3); Cr2O3 with other metals such as magnesium halides or zinc halides supported on Cr2O3; chromium(III) halides supported on carbon; mixtures of chromium and magnesium (including elemental metals, metal oxides, metal halides, and / or other metal salts) optionally supported on graphite; and mixtures of chromium and other metals (including elemental metals, metal oxides, metal halides, and / or other metal salts) optionally supported on graphite, alumina, or aluminum halides such as aluminum fluoride. Chromium-containing catalysts are well known in the art. They can be prepared either by precipitation methods or by impregnation methods such as those generally described by Satterfield on pages 87-112 in Heterogeneous Catalysis in Industrial Practice, 2nd edition (McGraw-Hill, New York, 1991). Of particular note are fluorination catalysts comprising at least one chromium-containing component selected from the group consisting of crystalline alpha-chromium oxide where 0.05 atomic percent to 6 atomic percent of chromium atoms in the chromium oxide lattice are replaced by trivalent cobalt atoms, and crystalline alpha-chromium oxide where 0.05 atomic percent to 6 atomic percent of chromium atoms in the chromium oxide lattice are replaced by trivalent cobalt atoms that have been treated with a fluorinating agent.These atalizers, including their preparation, have been described in United States Patent Application Publication Number US2005 / 0228202. Optionally, the catalysts containing the metals described above can be pretreated with HF. This pretreatment can be carried out, for example, by placing the metal-containing catalyst in a suitable container and then passing HF over it. This container can be the reactor used to perform the fluorination reaction described herein. Typically, the pretreatment time is 15 to 300 minutes, and the pretreatment temperature is 200°C to 450°C. The product mixture may comprise HFC-245cb, HFC-245fa, HFO-1234yf, HFO-1234ze, HCFO-1233zd and HCFO-1233xf. Fluorination of HCFO-1233xf HCFO-1233xf can be used to prepare HCFC-HCFC-244bb, and / or HFO-1234yf by fluorination. These reactions are shown in FIG. 1. The reaction of HCFO-1233xf to HCFC-244bb can be carried out in the liquid phase or in the vapor phase. The reaction of HCFO-1233xf to HCFC-244bb can be carried out in batch or continuous mode. A liquid-phase reaction of HCFO-1233xf to HCFC-244bb can be carried out in the presence of a catalyst. The catalyst can be a Lewis acid catalyst or a metal halide catalyst, or at least one catalyst selected from the group consisting of antimony halides, tin halides, thallium halides, iron halides, and combinations thereof. The catalysts can be at least one catalyst selected from antimony pentachloride (SbCl5), antimony trichloride (SbCl3), antimony pentafluoride (SbF5), tin tetrachloride (SnCl4), titanium tetrachloride (TiCl4), iron trichloride (FeCl3), and combinations thereof. The reaction can be carried out with any known fluorination catalyst for liquid-phase reactions. The reaction of HCFO-1233xf to HCFC-244bb can be carried out in the absence of a catalyst. A vapor-phase reaction of HCFO-1233xf to HCFC-244bb can be carried out in the presence of a catalyst. The reaction can be carried out in the presence of a chromium-based catalyst, an iron-based catalyst, or combinations thereof. In one embodiment, the chromium-based catalyst is a chromium oxide (e.g., Cr₂O₃). The iron-based catalyst can be FeCl₃ on carbon. The vapor-phase reaction of HCFO-1233xf to HCFC-244bb can be carried out in the absence of a catalyst. Dehydrochlorination of HCFC-244bb The dehydrochlorination of HCFC-244bb can be used to prepare HFO-1234yf. The dehydrochlorination of HCFC-244bb to HFO-1234yf can be carried out in the vapor phase. Vapor-phase dehydrochlorination can be carried out in the presence of a catalyst. The catalyst can be selected from carbon and / or metal-based catalysts, or from activated carbon, a nickel-based catalyst, a palladium-based catalyst, or any combination thereof. The catalyst can also be selected from the group consisting of nickel mesh, palladium on carbon, palladium on aluminum oxide, or combinations thereof. HFO-1234yf can be prepared by the thermal dehydrochlorination of HCFC-244bb. This reaction can occur in the absence of a catalyst. HCFC-244bb can be introduced into a reaction vessel whose temperature is maintained at a temperature high enough to effect the thermal dehydrochlorination of HCFC-244bb. The temperature can be high enough to effect the thermal dehydrochlorination of HCFC-244bb at a percentage conversion of at least 50%. The temperature can also be high enough to effect the thermal dehydrochlorination of HCFC-244bb at a percentage conversion of at least 65%. The temperature can be high enough to effect the thermal dehydrochlorination of HCFC-244bb at a percentage conversion of at least 80%.The temperature can be high enough to effect the thermal dehydrochlorination of HCFC-244bb to a percentage conversion of at least 70% for at least 12 hours of continuous operation. HCFC-244bb can be introduced into a reaction vessel whose temperature is maintained in the range of 500°C to 700°C or in the range of 500°C to 650°C. Alternatively, the temperature of the reaction vessel can be maintained high enough to effect the pyrolysis of HCFC-244bb to HFO-1234yf with a selectivity of 80% or greater. For example, the temperature of the reaction vessel can be maintained high enough to effect the pyrolysis of HCFC-244bb to HFO-1234yf with a selectivity of 85% or greater. The reaction zone may be a reaction vessel made of corrosion-resistant materials. These materials may include alloys such as nickel-based alloys like Hastelloy®, commercially available nickel-chromium alloys from Special Metals Corp. under the trademark Inconel® (hereinafter "Inconel®"), or commercially available nickel-copper alloys from Special Metals Corp. (New Hartford, New York) under the trademark Monel®, or vessels with fluoropolymer linings. HCFC-244bb can be preheated in a vaporizer at a temperature from 30°C to 100°C or at a temperature from 30°C to 80°C. An inert diluent gas can be used as a carrier gas for HCFC-244bb. The carrier gas can be selected from nitrogen, argon, helium, or carbon dioxide. Examples General procedure for product analysis The following general procedure illustrates the method used to analyze the products of the fluorination reactions. Part of the total reactor effluent was sampled online for analysis of the organic products using a gas chromatograph equipped with a mass selective detector (GC / MS). The gas chromatography used a 6.1 m (20 ft) long x 0.32 cm (1 / 8 in) diameter tube containing perfluorinated polyether sold under the trade name Kr and tox® by E.I. du Pont de Nemours and Company (hereafter "DuPont") of Wilmington, Delaware, on an inert carbon support. The helium flow rate was 30 mL / min (5.0 x 10⁻⁷ m³ / s). The gas chromatography conditions were 60°C for an initial retention time of three minutes, followed by a temperature program at 200°C at a rate of 6°C / min. Preparation of the 98% chromium / 2% cobalt catalyst A solution was prepared using 784.30 grams of Cr(NO3)3[9(H2O)2] (1.96 moles) and 11.64 grams of Co(NO3)2[6(H2O)2] (0.040 moles) in 2000 mL of deionized water. The solution was treated dropwise with 950 mL of 7.4 M aqueous ammonia until the pH reached approximately 8.5. The suspension was stirred overnight at room temperature and then evaporated to dryness in air at 110–120°C. The dried catalyst was then calcined in air at 400°C for 24 hours before use. Legend 243db is CF3CHClCH2Cl 244db is CF3CHClCH2F 245cb is CF3CF2CH3 245fa is CF3CH2CHF2 1234yf is CF3CF=CH2 1233xf is CF3CCl=CH2 1243zf is CH2=CHCF3 233ab is CF3CCl2CH2Cl 1233zd is E- and / or Z-CHCl=CHCF3 226ba is CF3CClFCHF2 1234ze is E- and / or Z-CHF=CHCF3 227ca is CF3CF2CHF2 1223xd is E- and / or Z-CF3CCl=CHCl 244bb is CF3CFClCH3 1141 is CHF=CH2 Reference examples 1-6 Chlorofluorination of HFO-1243zf The previously prepared 98% chromium / 2% cobalt catalyst (21.4 g, 15 mL, -12 to +20 mesh, (1.68 to 0.84 mm)) was placed in a 1.58 cm (5 / 8") diameter Inconel® nickel alloy reactor tube (Special Metals Corp. (New Hartford, New York)) heated in a fluidized sand bath. The catalyst was pre-fluorinated by HF treatment as follows. The catalyst was heated from 45°C to 175°C in a nitrogen flow (50 cc / min) over approximately 1.5 hours. HF was then introduced into the reactor at a flow rate of 50 cc / min for 1.3 hours at a temperature of 175°C. The nitrogen flow rate to the reactor was reduced to 20 cc / min, and the HF flow rate was increased to 80 cc / min. cc / min; this flow was maintained for 0.3 hours. The reactor temperature was then gradually increased to 400°C over 1 hour. After this period, the flow of HF and nitrogen was stopped, and the reactor was brought to the desired operating temperature.A steam flow of HF, HFO-1243zf, and Cl2 was then passed through the reactor. Part of the reactor effluent was analyzed using an online GC / MS. Table 2 shows the results of the chlorofluorination of HFO-1243zf over the Cr / Co 98 / 2 catalyst at various operating temperatures and the indicated molar ratios of HF, HFO-1243zf, and Cl2; analytical data are given in units of % of GC area. The nominal catalyst bed volume was 15 cc; the contact time (CT) was 15 seconds. Examples 1 and 2 were carried out in the absence of the catalyst. Table 2 (Part A) Chlorofluorination of HFO-1243zf Ex. No. T Ratio, °C 1243zf 243db 244db 1234yf 245cb 1233xf HF / 1243 / Cl2 1* 10 / 1 / 4 140 3, 0 54, 2 9, 8 5, 7 0 1, 4 2a* 10 / 1 / 1 140 31, 3 46, 2 11, 8 2, 8 0 1, 5 3b* 10 / 1 / 1 300 5, 9 0 0 5, 9 22, 2 30, 7 4c* 10 / 1 / 4 325 0 0 0 0 0 0 5* 10 / 1 / 1 350 9, 1 0 0 11, 3 11, 3 25, 2 6* 10 / 1 / 1 375 12, 8 0 0 11, 6 6, 3 20, 6 Table 2 (Part B) Chlorofluorination of HFO-1243zf Ex. No. T ratio, °C 1233zd 1234ze 245fa 1223xd 233ab 226ba 227ca HF / 1243 / Cl2 1* 10 / 1 / 4 140 7, 7 - - 1, 0 6, 3 0 0 2a* 10 / 1 / 1 140 1, 4 - - 0 1, 3 0 0 3b* 10 / 1 / 1 300 4, 1 2, 1 1, 3 20, 2 0 0 0 4c* 10 / 1 / 4 325 0 0 0 0 0 23, 8 13, 9 5* 10 / 1 / 1 350 12, 4 4, 7 1, 9 18, 1 0 0, 2 0 6* 10 / 1 / 1 375 17, 6 6, 5 2, 3 16, 1 0 0, 2 0 a.243db and 244db confirmed by 1H and 19F NMR. b.245cb and 1233xf confirmed by 1H and 19F MRI. c. The additional products were 215aa, 216aa, 216ba, 225aa, 225ba, 226ca, 226da. * Reference example Reference Examples 7-11 Fluorination of HCFC-243db The previously prepared 98% chromium / 2% cobalt catalyst (21.4 g, 15 mL, -12 to +20 mesh, (1.68 to 0.84 mm)) was placed in a 1.58 cm (5 / 8") diameter Inconel® nickel alloy reactor tube heated in a sand bath. The catalyst was pre-fluorinated by HF treatment as follows. The catalyst was heated from 45°C to 175°C in a nitrogen flow (50 cc / min) over approximately 1.5 hours. HF was then introduced into the reactor at a flow rate of 50 cc / min for 1.3 hours at 175°C. The nitrogen flow rate was reduced to 20 cc / min, and the HF flow rate was increased to 80 cc / min; this flow rate was maintained for 0.3 hours. The The reactor temperature was set to 400°C for 1 hour. After this period, the flow of HF and nitrogen was stopped, and the reactor was brought to the desired operating temperature. Then, a flow of HF steam and HCFC-243db (CF3CHClCH2Cl) was started through the reactor.Part of the reactor effluent was analyzed using an online GC / MS. Table 3 shows the results of the fluorination of HFC-243db over the 98 / 2 Cr / Co catalyst at various operating temperatures and the indicated molar ratios of HF and HCFC-243db; analytical data are given in units of % of GC area. The nominal volume of the catalyst bed was 15 cc; the contact time (CT) was 15 seconds. Example 7 was carried out in the absence of the catalyst. Table 3 Reference example 12 Reaction of HFC-243db with HF in the presence of TaFs A 210 mL Hastelloy® C tube was loaded with 10.0 g (0.0599 mol) of HCFC-243db and 25.4 g (0.040 mol) of tantalum pentafluoride. The tube was then loaded with 40.0 g (2.0 mol) of hydrogen fluoride. The tube was heated to 150°C and held at 149°C to 150°C for eight hours with stirring. The tube was then cooled to room temperature and treated with 100 mL of water. The contents of the tube were discharged, and a small organic layer was collected and neutralized. The sample was 91.1% unconverted HCFC-243db; the GC-MS analysis of the converted products was as follows: Table 4 Reference example 13 Fluorination of HCFO-1233xf to HCFC-244bb The contents of a small PTFE vial containing 20 grams of viscous SbF5 were poured into a dry 400 mL Hastelloy® shaker tube. The tube was pressurized with nitrogen and sealed leak-proof. The shaker tube was then cooled to below -40°C with dry ice, slowly vented, and then evacuated. 75 grams (3.75 moles) of anhydrous HF were condensed into the shaker tube, followed by 165 grams (1.26 moles) of HCFO-1233xf. The shaker tube was placed on a stand and shaken. The shaker tube was shaken at room temperature (~20–23°C) and the pressure was 144.79 to 172.37 kPa (21 to 25 psig). After 2 hours, shaking was stopped, and 150 mL of water was carefully pumped into the shaker tube. The tube was allowed to stand overnight and then cooled to 0–5°C in an ice bath before depressurization and transfer of the contents to a plastic container. The container was kept on ice. The contents of the container were poured into a polypropylene separatory funnel containing some ice. The lower organic layer was light amber in color. The organic layer was separated into a glass media bottle sold under the trademark Pyrex® by Corning (Lowell, MA) (hereafter "Pyrex®") containing ~50 ml of 4 molar phosphate buffer solution (pH 7) and ice (~100 ml). The organic layer was again separated and poured into a dry Pyrex® media bottle containing a small amount of anhydrous magnesium sulfate.The gross yield was 164.3 grams (approximately 120 ml, 86%). GC / MS analysis of the raw material showed that it was primarily HCFC-244bb. Other components included 0.13% 245cb, 0.09% 245eb, 0.16% 1233xf, and other byproducts totaled 12.2%. Reference example 14 Fluorination of HCFO-1233xf to HCFC-244bb The contents of a small PTFE vial containing 20 grams of viscous SbF5 were poured into a dry 400 mL Hastelloy® shaker tube. The tube was pressurized with nitrogen and sealed leak-proof. The shaker tube was then cooled to below -40°C with dry ice, slowly vented, and then evacuated. 53 grams (2.65 moles) of anhydrous HF were transferred to the shaker tube, followed by 227 grams (1.74 moles) of HCFO-1233xf, which condensed in the cooled shaker tube. The shaker tube was placed on the bench and shaken. The shaker tube was shaken at room temperature (~18–21°C) and the pressure was 110.32 to 137.90 kPa (16 to 20 psig). After 2 hours, shaking was stopped, and 100 mL of water was carefully pumped into the shaker tube. The tube was allowed to stand overnight and then cooled to 0–5°C in an ice bath before depressurization and transfer of the contents to a plastic container. The container was kept on ice. The contents of the container were poured into a polypropylene separatory funnel containing some ice. The lower organic layer was light amber in color. The organic layer was separated into a Pyrex® media bottle containing approximately 50 mL of 4 M phosphate buffer (pH 7) and ice (~100 mL). The organic layer was separated again and poured into a dry Pyrex® media bottle containing a small amount of anhydrous magnesium sulfate. The crude yield was 238.8 grams (approximately 170 mL, 91%). GC / MS analysis of the raw material indicated that it was primarily HCFC-244bb. Other components included 0.11% HFC-245cb, 0.10% HFC-245eb, 0.26% HCFO-1233xf, and other byproducts totaling 9.7%. Reference example 15 Example 15 demonstrates the conversion of HCFC-244bb (2-chloro-1,1,1,2-tetrafluoropropane) to HFO-1234yf (2,3,3,3-tetrafluoropropene) in the absence of a catalyst. An empty Inconel® tube (ID 1.27 cm (1 / 2 in)) with a heated zone of approximately 30.48 cm (12 in) was heated to a temperature between 500°C and 626°C, and HFC-244bb was fed at 0.52 mL / hr through a vaporizer set to 40°C using an N2 sweep stream of 2.4 sccm (4.0 x 10-8 m3). The reactor effluent was analyzed using an online GCMS, and the results are shown in molar percent. Table 5 Example 16 Example 16 demonstrates the conversion of HCFC-244bb (2-chloro-1,1,1,2-tetrafluoropropane) to HFO-1234yf (2,3,3,3-tetrafluoropropane) in the absence of a catalyst. An empty Inconel® tube (ID 1.27 cm (1 / 2 in.)) with a heated zone of approximately 30.48 cm (12 in.) was heated to 575°C, and HFC-244bb was fed at 0.35 mL / hr through a vaporizer set to 40°C using an N2 scavenging stream of 3.6 sccm (6.0 x 10⁻⁸ m³). The reactor was operated continuously for a total of 19 hours, and samples were taken periodically and analyzed to determine the % conversion of HFC-244bb and the selectivity to HFO-1234yf. The reactor effluent was analyzed using an online GCMS, and the data in Table 6 below are an average of at least two online injections under a given condition. The percentages are molar percentages. Table 6 Reference example 17 Example 17 demonstrates the dehydrochlorination of HCFC-244bb (2-chloro-1,1,1,2-tetrafluoropropane) in the presence of an activated carbon catalyst. An Inconel® tube (ID 1.27 cm (1 / 2 inch)) was filled with 4 cc (1.99 g) of acid-washed Polynesian coconut shell-based carbon (PCB) from Calgon (6-10 mesh). HFC-244bb was fed at 1.04 ml / hour through a vaporizer set to 40°C using an N2 scavenging stream of 2.4 sccm (4.0 x 10-8 m3) giving a total contact time of approximately 32 seconds while controlling the reactor temperature at 400°C. The data in Table 7 show the composition of the reactor effluent in molar percentage for this process executed with an activated carbon catalyst to prepare HFC-1234yf through the removal of HCl during a 7-hour operating period. Table 7

Claims

1. A composition comprising HCFC-244bb and at least one additional compound selected from the group consisting of HCFC-243xd, HCFC-233ab, HCFC-244db, HFC-245fa, and 253fb.

2. The composition of claim 1 comprising from more than zero percent by weight to approximately 99 percent by weight of HCFC-244bb.

3. The composition of claim 1 or 2, wherein the total amount of additional compound(s) in the composition ranges from more than zero percent by weight to approximately 99 percent by weight.

4. The composition of any of the preceding claims, wherein the total amount of additional compound(s) ranges from approximately 1 percent by weight to approximately 80 percent by weight.

5. The composition of any of the preceding claims, wherein the total amount of additional compound(s) ranges from approximately 1 percent by weight to approximately 50 percent by weight. 6.The composition of any of the preceding claims, wherein the total amount of additional compound(s) ranges from approximately 1 percent by weight to approximately 30 percent by weight.

7. The composition of any of the preceding claims, wherein the total amount of additional compound(s) ranges from approximately 1 percent by weight to approximately 10 percent by weight.

8. Use of the composition of any of claims 1 to 7 in a process for manufacturing HFO-1234yf.

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