Azeotrope or azeotrope-like compositions of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water

Abstract

To provide a composition comprising an azeotrope or azeotrope-like composition, and a method of forming the same.SOLUTION: There are provided heterogenous azeotrope or azeotrope-like compositions comprising 2-chloro- 1,1,1,2-tetrafluoropropane (HCFC-244bb) and water which may include from about 0.05 wt.% to about 92.01 wt.% 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and from about 7.99 wt.% to about 99.95 wt.% water and having a boiling point between about -13.5°C and about 14.5°C at a pressure of between about 12.5 psia and about 16.5 psia. The azeotrope or azeotrope-like compositions may be used to separate impurities from 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb).SELECTED DRAWING: Figure 1

Description

Technical Field

[0001]

[0001] The present disclosure relates to an azeotropic mixture or an azeotrope-like composition, and more particularly to an azeotropic mixture or an azeotrope-like composition containing an effective amount of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water.

Background Art

[0002]

[0002] Hydrofluoroolefins (HFOs) such as tetrafluoropropene containing 2,3,3,3-tetrafluoropropene (HFO-1234yf) are known to be effective refrigerants, heat transfer media, propellants, foaming agents, blowing agents, gas dielectrics, sterilant carriers, polymerization media, particle removal fluids, carrier fluids, buffing abrasives, replacement desiccants, and power cycle working fluids. Unlike chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs), both of which can potentially damage the Earth's ozone layer, HFOs do not pose a threat to the ozone layer. HFO-1234yf has also been shown to be a compound with low toxicity and a low global warming potential, and thus can meet the increasingly stringent requirements for refrigerants in mobile air conditioning systems. Therefore, compositions containing HFO-1234yf are one of the materials being developed for use in many of the aforementioned applications.

[0003]

[0003] One method for manufacturing HFO-1234yf uses 1,1,2,3-tetrachloropropene (HCFC-1230xa) as a starting material. This method includes the following three steps: Step (1) 1230xa + 3HF -> 2-chloro-3,3,3-trifluoropropene (1233xf) + 3HCl in a gas-phase reactor filled with a solid catalyst, Step (2) 1233xf + HF -> 2-chloro-1,1,1,2-tetrafluoropropane (244bb) in a liquid-phase reactor filled with a liquid catalyst, and Step (3) 244bb -> 1234yf + HCl in the liquid phase or in a gas-phase reactor. During the above methods, by-products may be produced and / or impurities may be present. To limit unwanted side reactions, it is desirable to have all reactants and intermediates in the highest possible purity form. Therefore, methods for reducing impurities in reactants and intermediates are desired. SUMMARY OF THE INVENTION

[0004]

[0004] The present disclosure provides an azeotropic mixture or azeotrope-like composition of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water.

[0005] It is well recognized in the art that it is impossible to predict the formation of an azeotropic mixture, and the inventors unexpectedly discovered that 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water form an azeotropic mixture or an azeotrope-like composition, specifically, a heterogeneous azeotropic mixture or an azeotrope-like composition.

[0005]

[0006] The present disclosure provides a composition comprising an azeotropic mixture or an azeotrope-like composition consisting essentially of an effective amount of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water, wherein the azeotropic mixture or the azeotrope-like composition preferably has a boiling point of about 13.5°C to about 14.5°C, preferably about 13.99°C to about 14.02°C at a pressure of about 12.5 psia to about 16.5 psia, preferably about 14.5 psia.

[0006]

[0007] An azeotropic mixture or azeotrope-like composition may consist essentially of from about 0.05 wt.% to about 92.01 wt.% of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and from about 7.99 wt.% to about 99.95 wt.% of water. The azeotropic mixture or azeotrope-like composition may consist essentially of from about 61 wt.% to about 90 wt.% of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and from about 10 wt.% to about 39 wt.% of water, or from 61.39 wt.% to about 88.29 wt.% of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and from about 11.71 wt.% to about 38.61 wt.% of water. The azeotropic mixture or azeotrope-like composition preferably has a boiling point of from about 13.5 °C to about 14.5 °C, preferably from about 13.99 °C to about 14.02 °C, at a pressure of from about 12.5 psia to about 16.5 psia, preferably about 14.5 psia.

[0007]

[0008] The present disclosure also provides a method of forming an azeotropic mixture or azeotrope-like composition, the method comprising combining 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water to form an azeotropic mixture or azeotrope-like composition consisting essentially of an effective amount of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water and having a boiling point of from about 13.5 °C to about 14.5 °C at a pressure of from about 12.5 psia to about 16.5 psia.

[0008]

[0009] The present disclosure provides a method for separating impurities from a composition comprising 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and at least one impurity, the method comprising the steps of: preparing a composition comprising 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and at least one impurity; changing the relative amounts of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water; and subjecting the composition to conditions effective to form an azeotropic or azeotrope-like mixture consisting essentially of or consisting of an effective amount of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water; and separating the azeotropic or azeotrope-like mixture from the composition comprising 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb), wherein the separating step may include at least one of phase separation, distillation, and fractionation. In this context, "impurity" (and "impurirties") includes substances intended to be separated from 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb), but the substances to be separated may have value per se. An example of such an "impurity" is 2,3,3,3-tetrafluoropropene (HFO-1234yf), a very valuable commercial product that can be sold to generate revenue. For the sake of emphasis, the claims refer to "other substances" instead of "impurities", and the terms "other substances" and "impurities" are intended to be used interchangeably in this context in the present disclosure.

[0009]

[0010] In the above method, the step of changing the relative amounts of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water may involve adding 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) to the composition, adding water to the composition, or adding both 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water to the composition.

[0010]

[0011] The present disclosure is a method for producing 2,3,3,3-tetrafluoropropene (HFO-1234yf), wherein at least a part of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) present in the azeotropic mixture or azeotrope-like composition defined above is converted to 2,3,3,3-tetrafluoropropene (HFO-1234yf ) to a method that also includes the step of converting to. This method includes both direct conversion (when HCFC-244bb is present in the azeotropic mixture at the time of conversion to HFO-1234yf) and indirect conversion (for example, when HCFC-244bb that was previously present in an azeotropic mixture or an azeotropic-like composition is not part of the azeotropic mixture or azeotropic-like composition at the time of conversion to HFO-1234yf). The latter possibility includes, for example, converting HCFC-244bb to HFO-1234yf in a reaction mixture that does not contain the azeotropic mixture / azeotropic-like composition of the present disclosure due to the presence of other substances that interfere with azeotropy, but where the HCFC-244bb molecule was previously in the form of an azeotropic mixture / azeotropic-like composition. The method may involve the step of reacting HCFC-244bb with a base, and the base may be a caustic base, preferably an alkali metal hydroxide, preferably KOH or NaOH. The reaction may be carried out in an aqueous environment, preferably in the presence of a phase transfer catalyst, preferably an ammonium halide, preferably a trialkylammonium halide or a tetraalkylammonium halide, preferably a trialkylammonium chloride or a tetraalkylammonium chloride. The step of converting 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) to 2,3,3,3-tetrafluoropropene (HFO-1234yf) may preferably be carried out at a temperature of about 0 °C to about 100 °C, preferably about 20 °C to about 90 °C, preferably about 50 °C to about 90 °C, preferably about 60 °C to about 80 °C. The step of converting 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) to 2,3,3,3-tetrafluoropropene (HFO-1234yf) may be appropriately carried out at a pressure above atmospheric pressure, atmospheric pressure, or below atmospheric pressure.

Brief Description of the Drawings

[0011]

Figure 1

[0012] A graph showing the plot of the boiling point against the percentage of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) in water.

Best Mode for Carrying Out the Invention

[0012]

[0013] In the first step (above), starting materials such as 1,1,2,3 - tetrachloropropene (“HCO - 1230xa” or “1230xa”) and / or 1,1,1,2,3 - pentachloropropane (“HCC - 240db” or “240db”) and / or 2,3,3,3 - tetrachloropropane (HCO - 1230xf) react with hydrogen fluoride anhydride (HF) in a first gas - phase reactor (fluorination reactor) to produce a mixture of at least HCFO - 1233xf (2 - chloro - 3,3,3 - trifluoropropene) and HCl. The reaction may be carried out at a temperature of about 200 °C to about 400 °C and a pressure of about 0 to about 200 psig. The effluent stream from the gas - phase reactor may optionally contain further components such as unreacted hydrogen fluoride (HF), heavy intermediates, 2 - chloro - 1,1,1,2 - tetrafluoropropane (HCFC - 244bb), 1,1,1,2,2 - pentafluoropropane (HFC - 245cb), etc.

[0013]

[0014] The reaction may be carried out in any reactor suitable for gas - phase fluorination reactions. The reactor may be constructed of a material resistant to the corrosive action of hydrogen fluoride and catalysts such as Hastelloy®, Inconel®, Monel®. In the case of the gas - phase process, the reactor is filled with a gas - phase fluorination catalyst. Any fluorination catalyst known in the art may be used in this method. Suitable catalysts include, but are not limited to, oxides, hydroxides, halides, oxyhalides of chromium, aluminum, cobalt, manganese, nickel and iron, their inorganic salts and their mixtures, any of which may optionally be halogenated. Combinations of catalysts suitable for the present invention non - exclusively include Cr2O3, FeCl3 / C, Cr2O3 / Al2O3, Cr2O3 / AlF3, Cr2O3 / carbon, CoCl2 / Cr2O3 / Al2O3, NiCl2 / Cr2O3 / Al2O3, CoCl2 / AlF3, NiCl2 / AlF3 and their mixtures. Chromium oxide The aluminum oxide catalyst is described in U.S. Patent No. 5,155,082, the content of which is incorporated herein by reference. Chromium(III) oxides such as crystalline chromium oxide or amorphous chromium oxide are preferred, with amorphous chromium oxide being most preferred. Chromium oxide (Cr2O3) is a commercially available material with various particle sizes. A fluorinated catalyst having a purity of at least 98% is preferred. The fluorinated catalyst is present in an excess amount, but in an amount sufficient to at least drive the reaction.

[0014]

[0015] In one embodiment, the molar ratio of hydrogen fluoride (HF) to the compound of Formula I, II, or III in the Step 1 reaction is in the range of about 1:1 to about 50:1 in one embodiment, about 10:1 to about 50:1 in another embodiment, and about 10:1 to about 20:1 in a further embodiment. In one embodiment, the reaction of HF with the compound of I, II, or III is carried out at a temperature of about 200°C to about 600°C, about 200°C to about 400°C in another embodiment, and about 200°C to about 300°C in another embodiment. The reaction pressure is in the range of about 0 psig to about 500 psig in one embodiment, about 20 psig to about 200 psig in another embodiment, and about 50 to about 100 psig in a further embodiment.

[0015]

[0016] For example, when the compound of Formula I is 1230xa, the molar ratio of HF to 1230xa in Step 1 of the reaction is in the range of about 1:1 to about 50:1 in one embodiment, about 10:1 to about 50:1 in another embodiment, and about 10:1 to about 20:1 in a further embodiment. In one embodiment, the reaction of HF with 1230xa is carried out at a temperature of about 200°C to about 600°C, about 200°C to about 400°C in another embodiment, and about 200°C to about 300°C in another embodiment. The reaction pressure is in the range of about 0 psig to about 500 psig in one embodiment, about 20 psig to about 200 psig in another embodiment, and about 50 to about 100 psig in a further embodiment.

[0016]

[0017] Similarly, when the compound of Formula II is 2,3,3,3 - tetrachloro - 1 - propene (HCC - 1230xf or 1230xf), the molar ratio of HF to 1230xf in step 1 of the reaction is, in one embodiment, from about 1:1 to about 50:1, in another embodiment from about 10:1 to about 50:1, and in a further embodiment from about 10:1 to about 20:1. In one embodiment, the reaction of HF and 1230xf is carried out at a temperature of about 200 °C to about 600 °C, in another embodiment from about 200 °C to about 400 °C, and in another embodiment from about 200 °C to about 300 °C. The reaction pressure is, in one embodiment, from about 0 psig to about 500 psig, in another embodiment from about 20 psig to about 200 psig, and in a further embodiment from about 50 to about 100 psig.

[0017]

[0018] Similarly, when the compound of Formula III is 1,1,1,2,3 - pentachloropropane (HCC - 240db or 240db), the molar ratio of HF to 240db in step 1 of the reaction is from about 1:1 to about 50:1, in another embodiment from about 10:1 to about 50:1, and in another embodiment from about 10:1 to about 20:1. The reaction of HF and 240db is carried out at a temperature of about 200 °C to about 600 °C, in one embodiment, in another embodiment from about 200 °C to about 400 °C, and in another embodiment from about 200 °C to about 300 °C. The reaction pressure is, in one embodiment, from about 0 psig to about 500 psig, in another embodiment from about 20 psig to about 200 psig, and in a further embodiment from about 50 to about 100 psig.

[0018]

[0019] The first step of the reaction is not necessarily limited to a gas - phase reaction as described above, and may be carried out using a liquid - phase reaction or a combination of liquid and gas phases, as disclosed in U.S. Patent Application Publication No. 20070197842, the content of which is incorporated herein by reference. It is also contemplated that the reaction may be carried out batchwise, continuously, or a combination thereof. In embodiments where the reaction includes a liquid - phase reaction, the reaction may or may not be catalyzed. Metal halides including antimony halides, tin halides, thallium halides, iron halides, and combinations of two or more of these Lewis acid catalysts such as catalysts can be used. In certain embodiments, without limitation, metal chlorides and metal fluorides including SbCl5, SbCl3, SbF5, SnCl4, TiCl4, FeCl3, and combinations of two or more thereof are used.

[0019]

[0020] The fluorination reaction may be carried out to achieve at least 1% or more, 5% or more, 10% or more, or about 20% or more single or multi-pass conversion. In certain preferred embodiments of the present invention, the starting reagent is converted to 1233xf in a single pass, and the reaction conditions achieve a conversion of more than 75%, more than 85% in one embodiment, more than 95% in another embodiment, and more than 99% in another embodiment. For this purpose, the resulting effluent may contain little or trace amounts of unreacted starting materials or may be substantially free of such compounds.

[0020]

[0021] The effluent from step 1, which is a fluorination reaction step and contains any intermediate effluent that may be present within the multi-stage reactor device, is processed to achieve a desired degree of separation. For example, in embodiments where the reactor effluent contains 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf), the effluent generally also contains HCl, unreacted HF, and, if any, trace amounts of unreacted starting components (such as 1230xa, 1230xf, and / or 240db). The effluent may also contain one or more by-product organic substances such as underfluorinated and / or overfluorinated intermediates. Non-limiting examples of underfluorinated intermediates include trichlorofluoropropene (1231) isomers and 2,3-dichloro-3,3-difluoropropene (1232xf), and non-limiting examples of overfluorinated intermediates include 2-chloro-1,1,1,2-tetrafluoropropane (244bb), 1,1,1,2,2-pentafluoropropane (245cb), and HFO-1234yf and combinations thereof. In further embodiments, the impurity is hydrogen fluoride. Other by-product organic substances may include, but are not limited to, dichlorotrifluoropropane (243) isomers, and trichlorodifluoropropane (242) isomers, and dimers derived from one or more of the starting compounds. As non-limiting examples, dimers derived from 1230xa include, but are not limited to, C6H3F6Cl, C6H3F7Cl2, C6F6Cl2, C6H8Cl2, C6F5Cl3, C6H3F2Cl5, etc.

[0021]

[0022] After HCl is removed by distillation and a portion of HF is removed by phase separation, water is added to the remaining effluent from step 1 in an amount effective to form an azeotropic or azeotrope-like mixture containing 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) and water, and then may be separated from the effluent along with its impurities by the techniques described herein. The 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) is then separated from water as described herein and then fed to the hydrofluorination reactor of step 2, which is discussed below.

[0022]

[0023] In step 2 of the aforementioned method for forming 2,3,3,3-tetrafluoroprop-1-ene, the purified 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) is converted to 2-chloro-1,1,1,2-tetrafluoropropane (244bb). In one embodiment, this step may be carried out in the liquid phase within a liquid phase reactor which may be lined with TFE or PFA. Such a method may be carried out at a temperature range of about 70 °C to about 120 °C and a pressure in the range of about 50 to about 120 psig.

[0023]

[0024] Any liquid phase fluorination catalyst may be used in the present invention. A non-exhaustive list includes Lewis acids, transition metal halides, transition metal oxides, Group IVb metal halides, Group Vb metal halides, or combinations thereof. Non-exclusive examples of liquid phase fluorination catalysts are antimony halides, tin halides, tantalum halides, titanium halides, niobium halides, and molybdenum halides, iron halides, fluorinated chromium halides, fluorinated chromium oxides or combinations thereof. Specific non- exclusive examples of liquid phase fluorination catalysts are SbCl5, SbCl3, SbF5, SnCl4, TaCl5, TiCl4, NbCl5, MoCl6, FeCl3, fluorinated species of SbCl5, fluorinated species of SbCl3, fluorinated species of SnCl4, fluorinated species of TaCl5, fluorinated species of TiCl4, fluorinated species of NbCl5, fluorinated species of MoCl6, fluorinated species of FeCl3, or combinations thereof. Antimony pentachloride is most preferred.

[0024]

[0025] When deactivated, the catalyst can be readily regenerated by any means known in the art. One suitable method of regenerating the catalyst involves flowing a stream of chlorine through the catalyst. For example, about 0.91 g (0.002 lb) to about 90.7 g (0.2 lb) of chlorine per hour may be added to the liquid phase reaction for 453.6 g (1 pound) of the liquid phase fluorination catalyst. This may be carried out, for example, at a temperature of about 65 °C to about 100 °C for about 1 to about 2 hours, or continuously.

[0025]

[0026] Step 2 of the reaction, in which the 244bb product is formed, is not necessarily limited to a liquid-phase reaction and may be carried out using a gas-phase reaction or a combination of liquid and gas phases, as disclosed in U.S. Patent Application Publication No. 20070197842, the content of which is incorporated herein by reference. For this purpose, a feed stream containing 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) is preheated to a temperature of about 50°C to about 400°C and contacted with a catalyst and a fluorinating agent. The catalyst may include standard gas-phase reagents used in such reactions, and the fluorinating agent may include those commonly known in the art, such as, but not limited to, hydrogen fluoride.

[0026]

[0027] The effluent from the hydrofluorination reaction step (step 2), consisting mainly of 244bb and HF (along with smaller amounts of unreacted 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf), perfluorinated byproduct 245cb, HCl, and Cl2), is processed to achieve a desired degree of separation and / or other treatments. For example, the product stream is fed to a lights removal column, where a stream consisting mainly of 245cb, HCl, and Cl2 exits from the top of the column and is sent to a thermal oxidizer (T-OX) for decomposition. In one embodiment, water is added to the bottoms stream of the lights removal column, which consists mainly of 244bb and HF (along with smaller amounts of unreacted 1233xf), to form an azeotropic or azeotrope-like mixture composed of 1233xf and water. In one embodiment, 244bb is not present in this mixture, in which case 1233xf is separated from water by techniques known in the art as described earlier herein, such as distillation. In another embodiment, 244bb is also present in the azeotropic or azeotrope-like mixture composed of 1233xf and water. Then 244bb is separated from 1233xf by techniques known in the art, such as those described in U.S. Patent No. 8,252,965, the contents of which are incorporated by reference. The separated 1233xf may be recycled back to the hydrofluoronation reactor of step 2 as described earlier.

[0027]

[0028] Step 3 of this process may be carried out in the gas phase or the liquid phase. When producing HFO-1234yf in the gas phase, 244bb is fed to a second gas-phase reactor (dehydrochlorination reactor) where it is dehydrochlorinated to produce the desired product, 2,3,3,3-tetrafluoroprop-1-ene (1234yf). This reactor may optionally contain a catalyst capable of dehydrochlorinating HCFC-244bb catalytically to produce HFO-1234yf, but in one embodiment, the reactor contains a catalyst.

[0028]

[0029] The catalyst may be a metal halide, a metal halide oxide, a neutral (i.e., zero oxidation state) metal or metal alloy, or activated carbon in bulk or supported form. The metal halide or metal oxide catalyst may include, but is not limited to, monovalent, divalent, and trivalent metal halides, oxides, and mixtures / combinations thereof, more preferably monovalent and divalent metal halides and mixtures / combinations thereof. The component metals may include, but are not limited to, Cr 3+ , Fe 3+ , Mg 2+ , Ca 2+ , Ni 2+ , Zn 2+ , Pd 2+ , Li + , Na + , K + , and Cs + . The component halogens may include, but are not limited to, F - , Cl - , Br - , and I - . Examples of useful monovalent or divalent metal halides include, but are not limited to, LiF, NaF, KF, CsF, MgF2, CaF2, LiCl, NaCl, KCl, and CsCl. The halogenation treatment may include any of those known in the prior art, particularly those utilizing HF, F2, HCl, Cl2, HBr, Br2, HI, and I2 as the halogenation source.

[0029]

[0030] In one aspect, neutral metals, i.e., zero-valent metals, metal alloys and mixtures thereof are used. Useful metals include, but are not limited to, Pd, Pt, Rh, Fe, Co, Ni, Cu, Mo, Cr, Mn, and combinations of the foregoing as alloys or mixtures. The catalyst may or may not be supported. Examples of useful metal alloys include, but are not limited to, SS316, Monel® 400, Incoloy® 825, Inconel® 600, and Inconel® 625. Such catalysts may be provided as individual supported or unsupported elements, and / or as part of and / or as the walls of a reactor.

[0030]

[0031] Exemplary but non-limiting catalysts include activated carbon, stainless steel (e.g., SS316), austenitic nickel-based alloys (e.g., Inconel® 625), nickel, 10% fluorinated CsCl / MgO, and 10% CsCl / MgF2, etc. In one embodiment, the reaction temperature may range from about 300 to about 550 °C and the reaction pressure may range from about 0 to about 150 psig. The reactor effluent may be fed to a caustic scrubber or distillation column to remove HCl by-products, producing an acid-free organic product, which may optionally be further purified using one or any combination of purification techniques known in the art.

[0031]

[0032] Step 3 can be carried out even in the liquid phase. The conversion of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) to 2,3,3,3-tetrafluoropropene (HFO-1234yf) can be carried out, for example, by utilizing a base for dehydrochlorination of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb). The base may be a caustic base and is preferably selected from the group consisting of alkali metal hydroxides, alkali metal oxides, alkaline earth metal hydroxides, alkaline earth metal oxides, and combinations thereof. Examples of preferred caustic bases are KOH, NaOH, LiOH, Mg(OH)2, Ca(OH)2, CaO, and combinations thereof. The caustic base may be added to the reaction in solid form or as a solution. When supplied as a solution, the solvent is preferably water or an alcohol, preferably MeOH or EtOH. KOH is particularly preferred and is preferably supplied as an aqueous solution, preferably an aqueous solution containing from about 5 wt% to about 62 wt% KOH, preferably 5 wt% to 55 wt%. The dehydrochlorination in the liquid phase is preferably carried out in an aqueous environment. In the context of the liquid phase Step 3, the aqueous environment is one in which the liquid reaction mixture contains 5 to 80 wt.% water, preferably 10 to 60 wt.% water, more preferably 20 to 40 wt.% water. Since it is considered that the reactivity is assisted by promoting intimate contact between the base and 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb), it is also preferable to utilize a phase transfer catalyst, particularly when carrying out the reaction in an aqueous environment. Such phase transfer catalysts may include, but are not limited to, crown ethers (e.g., 18-crown-6), onium salts (e.g., phosphonium salts or ammonium salts having halide anions), cryptands (e.g., N[CH2CH2OCH2CH2OCH2CH2]3N), polyalkylene glycols (e.g., poly(ethylene glycol)), derivatives thereof, and combinations thereof. One In an embodiment, the phase transfer catalyst is Aliquat 336. An onium salt, particularly an ammonium salt, is preferred. The ammonium salt is preferably an ammonium halide, preferably a trialkylammonium halide or a tetraalkylammonium halide, preferably a trialkylammonium chloride or a tetraalkylammonium chloride.

[0032]

[0033] The liquid phase version of Step 3 is preferably carried out at a temperature of about 0 °C to about 100 °C, preferably about 20 °C to about 90 °C, preferably about 50 °C to about 90 °C, preferably about 60 °C to about 80 °C. The conversion of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) to 2,3,3,3-tetrafluoropropene (HFO-1234yf) may be suitably carried out at a pressure above atmospheric pressure, at atmospheric pressure, or at a pressure below atmospheric pressure. These temperatures and pressures are particularly useful when carrying out Step 3 in a liquid phase having a base, as described above.

[0033]

[0034] WO-2011 / 139646, the content of which is incorporated herein, discloses further details of experiments for converting 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) to 2,3,3,3-tetrafluoropropene (HFO-1234yf) in a liquid phase.

[0034]

[0035] An alternative method for making HFO-1234yf utilizes 1,2-dichloro-3,3,3-trifluoropropane (HCFC-243db) as a starting material and is carried out in the gas phase and in the liquid phase. In this alternative method, the method comprises the following three steps (Steps (2) and (3) are the same as those above): Step (1): 243db → 1233xf + HCl in the gas phase (with or without a catalyst) or 243db + base → 1233xf + H2O in the liquid phase (optionally having a phase transfer catalyst, and / or a solvent and / or a salt).

[0035] Step (2): In a liquid-phase reactor loaded with a liquid hydrogen fluoride catalyst, 1233xf + HF → 244bb, and Step (3): 244bb → 1234yf + HCl in a gas-phase reactor (with or without a catalyst) or in a liquid phase.

[0036]

[0036] In an alternative process where the starting composition contains 243db, 243db is dehydrohalogenated to produce a product mixture containing 1233xf. When the starting composition contains 243db, the dehydrohalogenation reaction is a dehydrochlorination reaction. The dehydrochlorination reaction is carried out within a reaction compartment, in the gas phase with a catalyst, or in the liquid phase with a base and optionally a phase transfer catalyst, and / or a solvent and / or a salt. For example, WO2012 / 115934 discloses the gas-phase reaction of 243db with a carbon catalyst. WO2012 / 115938 discloses the gas-phase reaction of 243db with a chromium oxyfluoride catalyst. WO2017 / 044719 discloses the reaction of 243db with a fluorinated alkane in the presence of a fluorination catalyst to produce 1233xf, and further other compounds useful for producing 1234yf. WO2017 / 044724 discloses the liquid-phase reaction of 243db with caustic alkali. When the dehydrochlorination reaction is carried out in the gas phase, HCl is produced, while when the dehydrochlorination reaction is carried out in the liquid phase, HCl is not produced. As known to those skilled in the art, other processes may be used when starting with a compound having formula (III).

[0037]

[0037] In a preferred embodiment where it is desirable to maintain moisture- and impurity-free conditions during the synthesis of 1234yf, the reactants and intermediate products may be purified. For example, it is desirable to remove impurities from 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf). preferably.

[0038]

[0038] It has been found that 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water form a heterogeneous azeotropic mixture and an azeotrope-like composition or mixture, and the present disclosure provides a heterogeneous azeotropic mixture or an azeotrope-like composition containing 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water. The azeotropic mixture or azeotrope-like composition may consist essentially of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water, or the azeotropic mixture or azeotrope-like composition may consist of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water.

[0039]

[0039] The inventors have experimentally found that 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water form an azeotropic mixture or an azeotrope-like composition.

[0040]

[0040] The heterogeneous azeotropic mixture consists entirely of two liquid phases and one gas phase in equilibrium. In the heterogeneous azeotropic mixture at a given temperature and pressure, the composition of each of the two liquid phases and the composition of the gas phase remain constant. When a heterogeneous azeotropic mixture is formed, at a constant pressure, the boiling point of the heterogeneous azeotropic mixture is lower than that of the component with the lower boiling point ("minimum boiling azeotropic mixture").

[0041]

[0041] An "azeotropic mixture" (or "azeotropy") composition is a unique combination of two or more components. An azeotropic mixture can be either homogeneous (having one liquid phase) or heterogeneous (having two liquid phases). Azeotropic mixture compositions can be characterized in various ways. For example, at a given pressure, an azeotropic mixture composition boils at a certain characteristic temperature that is either above the higher boiling component (maximum boiling azeotropic mixture) or below the lower boiling component (minimum boiling azeotropic mixture). However, in the case of a heterogeneous azeotropic mixture, the boiling point of the azeotropic mixture is always below the boiling point of the lower boiling component. At this characteristic temperature, a homogeneous azeotropic mixture has the same composition in both the gas phase and the liquid phase. In the case of a heterogeneous azeotropic mixture, at this characteristic temperature, the composition of each of the two liquid phases and the gas phase remains constant during boiling. An azeotropic mixture composition does not fractionate upon boiling or evaporation. Therefore, the components of an azeotropic mixture composition cannot be separated during a phase transition.

[0042]

[0042] A homogeneous azeotropic mixture composition is also characterized in that at the characteristic azeotropic mixture temperature, the boiling point pressure of the liquid phase is the same as the dew point pressure of the gas phase. The behavior of an azeotropic mixture composition is in contrast to that of a non-azeotropic mixture composition in which the liquid composition changes to a significant degree during boiling or evaporation.

[0043]

[0043] However, those skilled in the art understand that at different pressures, both the composition and the boiling point of an azeotropic mixture composition vary to some extent. Therefore, depending on the temperature and / or pressure, an azeotropic mixture composition can have a variable composition. Therefore, those skilled in the art understand that a composition range, rather than a fixed composition, can be used to define an azeotropic mixture composition. Further, an azeotropic mixture can be defined in terms of the exact weight percentages of the components of the composition, which is characterized by a fixed boiling point at a specific pressure.

[0044]

[0044] An "azeotrope-like" composition is a composition of two or more components that behaves substantially as an azeotropic mixture. Thus, for the purposes of this disclosure, an azeotrope-like composition, in the case of a homogeneous azeotrope, boils at a substantially constant temperature if in liquid form under a given pressure, yielding a gas composition that is substantially the same as the liquid composition undergoing boiling. It is a combination of two or more different components. In the case of a heterogeneous azeotrope, two liquid phases covered by a gas composition are formed under a given pressure. Each of the two liquid phases and the gas phase remain substantially constant during boiling. and.

[0045]

[0045] For the purposes of this disclosure, an azeotrope-like composition is a composition or range of compositions that boils in a temperature range of about 12.0 °C to 13.6 °C and at a pressure of about 12.5 psia to about 16.5 psia.

[0046]

[0046] An azeotropic mixture or an azeotrope-like composition can be identified using a plurality of different methods.

[0047] For the purposes of this disclosure, an azeotropic mixture or an azeotrope-like composition is identified experimentally using an ebulliometer (Walas, Phase Equilibria in Chemical Engineering, Butterworth-Heinemann, 1985, 533 - 544). An ebulliometer is designed to provide a very accurate measurement of the boiling point of a liquid by measuring the temperature of the vapor-liquid equilibrium.

[0047]

[0048] The boiling point of each component alone is measured at a constant pressure. As will be understood by those skilled in the art, for a binary azeotropic mixture or an azeotrope-like composition, the boiling point of one of the components of the composition is measured first. Then the second component of the composition is added in various amounts, and the boiling point of each of the resulting compositions is measured using an ebulliometer at the said constant pressure. In the case of a ternary azeotropic mixture, the initial composition contains a binary mixture, and the third component is added in various amounts. The boiling point of each of the resulting ternary compositions is measured using an ebulliometer at the said constant pressure.

[0048]

[0049] The measured boiling points are plotted against the composition of the tested composition, e.g., in a binary azeotropic mixture, the amount of the second component added to the composition (expressed either as weight % or mole %). The presence of an azeotropic mixture composition can be identified by observation of a maximum or minimum boiling point that is above or below the boiling point of either of the components alone.

[0049]

[0050] As will be appreciated by those skilled in the art, the identification of an azeotropic or azeotrope-like mixture is made by comparing the boiling point change of the composition upon addition of a second component to the first component, relative to the boiling point of the first component. Thus, the system need not be calibrated to the reported boiling points of the specific components in order to measure the boiling point change.

[0050]

[0051] As previously discussed, at the maximum or minimum boiling point, the composition of the gas phase is the same as that of the liquid phase. Thus, an azeotrope-like mixture composition is a composition of components that results in a substantially constant minimum or maximum boiling point, i.e., a boiling point of about 13.5 °C to about 14.5 °C, at a pressure of about 12.5 psia to about 16.5 psia, and at which substantially constant boiling point, the composition of the gas phase is substantially the same as that of the liquid phase.

[0051]

[0052] The present disclosure provides an azeotropic or azeotrope-like mixture composition comprising an effective amount of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water for forming an azeotropic or azeotrope-like mixture. As used herein, the term "effective amount" is the amount of each component that, when combined with other components, results in the formation of an azeotropic or azeotrope-like mixture.

[0052]

[0053] The present azeotropic or azeotrope-like mixture composition may consist essentially of a combination of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water, or may consist of a combination of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water.

[0053]

[0054] As used herein, the term "consisting essentially of" with respect to the components of an azeotropic mixture or azeotrope-like composition or mixture means that the composition contains the indicated components in azeotropic or azeotrope-like ratios and may contain additional components, provided that the additional components do not form a new azeotropic or azeotrope-like system. For example, an azeotropic mixture consisting essentially of two compounds may optionally contain one or more additional components, provided that the additional components do not render the mixture non-azeotropic and do not form an azeotrope with either or both of the compounds (e.g., do not form a ternary or higher azeotrope), and is an azeotropic mixture that forms a binary azeotrope.

[0054]

[0055] The present disclosure also provides a method of forming an azeotropic mixture or azeotrope-like composition by mixing, combining, or admixing an effective amount of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water. Any of a variety of methods known in the art for combining two or more components to form a composition may be used in the method. For example, 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water may be mixed, admixed, or otherwise combined by hand and / or mechanically as part of a batch or continuous reaction and / or process, or by a combination of two or more such steps. The components may be supplied in the required amounts, for example, by weighing and then combining the amounts.

[0055]

[0056] The azeotropic mixture or azeotrope-like composition may have a boiling point of about 13.5 °C to about 14.5 °C at a pressure of about 12.5 psia to about 16.5 psia and consists essentially of or consists of about 0.05 wt.% to about 92.01 wt.% of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and about 7.99 wt.% to about 99.95 wt.% of water.

[0056]

[0057] ​The present disclosure also provides a composition comprising an azeotropic mixture or an azeotrope-like composition. For example, a composition comprising at least about 14 wt.% of an azeotropic mixture or an azeotrope-like composition, or at least about 21 wt.% of an azeotropic mixture or an azeotrope-like composition, or at least about 25 wt.% of an azeotropic mixture or an azeotrope-like composition, or at least about 70 wt.% of an azeotropic mixture or an azeotrope-like composition, or at least about 90 wt.% of an azeotropic mixture or an azeotrope-like composition, or at least 95 wt.% of an azeotropic mixture or an azeotrope-like composition, or at least 99 wt.% of an azeotropic mixture or an azeotrope-like composition is provided.

[0057]

[0058] An azeotropic mixture or an azeotrope-like composition consisting essentially of or consisting of an effective amount of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water, as disclosed herein, can be used to separate impurities from 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb).

[0058]

[0059] The preparation of an azeotropic or azeotrope-like composition consisting essentially of or consisting of an effective amount of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water enables separation techniques such as azeotropic distillation that are used to remove impurities from, for example, 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb).

[0059]

[0060] In particular, an azeotropic mixture or an azeotrope-like composition consisting essentially of or consisting of an effective amount of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water may be formed from a composition comprising 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb), water, and at least one impurity. Following the formation of the azeotropic mixture or azeotrope-like composition, the azeotropic mixture or azeotrope-like composition can be separated from other chemical compounds by suitable methods such as distillation, phase separation, or fractionation. It may be separated from the substance.

[0060]

[0061] In one example, the present disclosure provides a method for separating impurities from 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb), the method including: preparing a primary composition of unpurified 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb); changing the relative amounts of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water and applying conditions effective to form a secondary composition that is an azeotropic or azeotrope-like composition consisting essentially of or consisting of effective amounts of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water to the primary composition; and separating the secondary composition from the primary composition by a separation technique such as phase separation, distillation, or fractionation. The secondary composition may then be subjected to further separation or purification steps to obtain purified 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb). The step of changing the relative amounts of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water may involve adding 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) to the composition, adding water to the composition, or adding both 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water to the composition.

[0061]

[0062] An azeotropic or azeotrope-like composition comprising an effective amount of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water, consisting essentially of or consisting of these, can be used in the production of 2,3,3,3-tetrafluoropropene (HFO-1234yf). For example, the azeotropic or azeotrope-like composition may be combined with additional components such as a base and / or a phase transfer catalyst to facilitate the dehydrochlorination of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) to form 2,3,3,3-tetrafluoropropene (HFO-1234yf). The remaining 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) present in the unpurified 2,3,3,3-tetrafluoropropene (HFO-1234yf) may be removed together with water in the form of the azeotropic or azeotrope-like composition of the present disclosure, and the removal may take the form of, for example, distillation, phase separation, or a combination thereof. The azeotropic or azeotrope-like composition removed from the unpurified product may be recycled back to step 3, especially when performing step 3 in the liquid phase.

[0062]

[0063] Although not inevitable, an azeotropic or azeotrope-like composition may also occur in the reaction to produce 2,3,3,3-tetrafluoropropene (HFO-1234yf) from 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb). The presence of an azeotropic or azeotrope-like composition depends on factors such as whether the azeotropy is hindered by other substances present. Although not inevitable, examples of how an azeotropic or azeotrope-like composition may occur include the following: · When water is present as a solvent during the reaction, for example, when the reaction is carried out in an aqueous environment such as when a base is used in an aqueous solution.

[0063] · When water is generated in the reaction. For example, when HCFC-244bb is dehydrochlorinated by hydroxide ions in the presence or absence of water as a solvent, water molecules are generated according to the following equation: CF3CFClCCH3 +- OH → CF3CF=CH2 + Cl - + H2O. Those skilled in the art will understand that water molecules may be generated when other types of bases, especially caustic bases, are used.

[0064]

[0064] The following non-limiting examples serve to illustrate the present invention.

Example

[0065] Example 1 - Vapor-Liquid Equilibrium (VLE) Study

[0065] An ebulliometer consisting of a vacuum-jacketed tube with a dry-ice cooling condenser at the top was further equipped with a quartz thermometer. First, 16.21 grams of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) was loaded into the ebulliometer. Then water was added incrementally and the boiling point temperature of the mixture was recorded. The results are shown in Table 1 and illustrated in Figure 1.

[0066]

Table 1

[0067]

[0066] As shown, the boiling point temperature of the mixture reached a minimum value and then leveled off, indicating the formation of a heterogeneous azeotrope. More specifically, compositions containing from about 61 wt% to about 99 wt% of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) had a boiling point change of less than 0.2 °C. Further, compositions containing from about 66 wt% to about 99 wt% of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) had a boiling point change of less than 0.1 °C. The ambient pressure during the measurement was 14.49 psia.

[0068] Example 2 - Vapor-Liquid-Liquid Equilibrium (VLLE) Measurement A 50:50 by weight mixture of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water was prepared in a Teflon® cell at 23 °C. Two separate phases were observed in the cell, indicating that an azeotropic mixture was formed. The upper phase (water-rich) and the lower phase (2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb)-rich) were separated and analyzed. The compositions of the two phases are shown in Table 2 below.

[0069]

Table 2

[0070] Example 3 - Purification of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb)

[0068] In this example, a composition containing 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and possible impurities such as HF is provided. An effective amount of water is added to the composition, and the composition is subjected to conditions effective to form an azeotropic mixture or an azeotrope-like composition consisting essentially of or consisting of an effective amount of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water. The azeotropic mixture or azeotrope-like composition is then separated from the composition containing the primary compound by separation techniques such as phase separation, distillation, and / or fractionation.

[0071] Example 4 - Separation of hydrogen fluoride (HF) from 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb)

[0069] In this example, a composition containing hydrogen fluoride (HF) as an impurity and the primary compound 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) is prepared. An effective amount of water is added to the composition, and the composition is subjected to conditions effective to form an azeotropic mixture or an azeotrope-like composition consisting essentially of or consisting of an effective amount of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water. The azeotropic mixture or azeotrope-like composition is then separated from the composition containing the primary compound by separation techniques such as phase separation, distillation, and / or fractionation.

[0072] Example 5 - Separation of Hydrogen Fluoride (HF) from 2-Chloro-1,1,1,2-Tetrafluoropropane (HCFC-244bb)

[0070] In this example, a composition containing a primary compound such as 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) together with hydrogen fluoride (HF) as an impurity is prepared. An effective amount of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) is added to the composition, and the composition is subjected to conditions effective to form an azeotropic mixture or an azeotrope-like composition consisting essentially of or consisting of an effective amount of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water. The azeotropic mixture or azeotrope-like composition is then separated from the composition containing the primary compound by separation techniques such as phase separation, distillation, and / or fractionation.

[0073] Example 6 - Representative Procedure for Converting 2-Chloro-1,1,1,2-Tetrafluoropropane (HCFC-244bb) to 2,3,3,3-Tetrafluoropropene (HFO-1234yf)

[0071] The dehydrochlorination of HCFC-244bb was carried out in a 1-liter Parr reactor equipped with a thermocouple and a magnetic stirrer. 15 g of Aliquat 336 (trademark) was added to the reactor. The reactor was then closed and the pressure was tested. Thereafter, 294 g of the organic mixture and 270 g of 45% KOH were added to the reactor. Analysis of the organic mixture using gas chromatography (GC) showed 8.1 GC area % of 1234yf, 89.5 GC area % of 244bb, and 1.8 GC area % of 1233xf. The stirrer was then operated and the reactor was heated to 55 °C. When 55 °C was reached (after about 2 hours), the pressure inside the reactor increased from an initial 10 psig to 55 psig. The reactor was held at 55 °C for 4 hours and the pressure further increased to 78 psig. GC analysis of the organic content of the reactor after the reaction was completed, showing 64.2 GC area % of 1234yf, 33.2 GC area % of 244bb, 2.2 GC area % of 1233xf, and 0.4 GC area % of an unknown substance.

[0074] The synthetic examples described above are included to illustrate the reactions and are not an explanation of whether the claimed azeotropic mixture or azeotrope-like composition is present during the synthesis procedure. Example 7 - Representative Purification of HCFC-244bb

[0072] A composition containing HCFC-244bb and water is purified to yield a purified stream of HCFC-244bb.

[0075]

[0073] 1000 kg of a mixture containing 920.1 kg of HCFC-244bb and 79.9 kg of water is charged to the reboiler of a batch distillation facility consisting of a multi-stage rectification section packed with random packing such as IMTP (registered trademark) packing available from Koch-Glitsch and a condenser. The condenser is cooled with flowing water cooled to about 5 °C at the inlet to the condenser. The reboiler has a half-pipe jacket for steam. The reboiler charge may be the organic phase of a mixture of HFC-244bb and water that has been subjected to phase separation and from which the aqueous phase has been removed by decantation from the top.

[0076]

[0074] A batch distillation facility is used to distill the overhead stream substantially containing the azeotropic mixture of HCFC-244bb and water, and HCFC-244bb containing about 0.05 wt% of water remains substantially in the reboiler (see Table 3). The material in the reboiler may be further dried by passing through a desiccant such as 3A molecular sieve.

[0077]

Table 3

[0078] This example shows purification in a batch distillation mechanism, which may be adapted by those skilled in the art for continuous distillation for purification. Aspect

[0075] Aspect 1 is a composition comprising an azeotropic mixture or azeotrope-like composition consisting essentially of an effective amount of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water.

[0079]

[0076] Aspect 2 is the composition of Aspect 1, wherein the azeotropic mixture or azeotrope-like composition has a boiling point of about 13.5 °C to about 14.5 °C at a pressure of about 12.5 psia to about 16.5 psia.

[0080]

[0077] Aspect 3 is the composition of Aspect 1 or Aspect 2, wherein the azeotropic mixture or azeotrope-like composition consists essentially of about 0.05 wt.% to about 92.01 wt.% of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and about 7.99 wt.% to about 99.95 wt.% of water. the composition of Aspect 1 or Aspect 2.

[0081] Aspect 4 is a method of forming an azeotropic mixture or an azeotrope-like composition, which comprises combining 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water, and forming an azeotropic mixture or an azeotrope-like composition that consists essentially of an effective amount of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water and has a boiling point of about 13.5 °C to about 14.5 °C at a pressure of about 12.5 psia to about 16.5 psia.

[0082] Aspect 5 is the method of Aspect 4, wherein the combining step comprises combining about 0.05 wt.% to about 99.95 wt.% of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and about 7.99 wt.% to about 99.95 wt.% of water.

[0083] Aspect 6 is a method of separating impurities from 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) in a composition containing 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and at least one impurity, which comprises preparing a composition containing 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and at least one impurity, changing the relative amounts of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water, and applying to the composition conditions effective to form an azeotropic mixture or an azeotrope-like composition consisting essentially of or consisting of an effective amount of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water, and separating an azeotropic mixture or an azeotrope-like composition from the composition containing 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb).

[0084] Aspect 7 is the method of Aspect 6, wherein the step of changing the relative amounts of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water includes the step of adding 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) to the composition.

[0085] Aspect 8 is the method of Aspect 6 or Aspect 7, wherein the step of changing the relative amounts of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water includes the step of adding water to the composition.

[0086] Aspect 9 is the method of any one of Aspects 6 to 8, wherein the step of changing the relative amounts of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water includes the step of adding both 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water to the composition.

[0087] Aspect 10 is the method of any one of Aspects 6 to 9, wherein the separation step includes at least one of phase separation, distillation, and fractionation. As used herein, the phrase "within any range defined between any two of the above values" literally means that any range may be selected from any two of the values listed before such phrase, regardless of whether the value is the smaller or the larger of the listed items. For example, a pair of values may be selected from the two smaller values, the two larger values, or the smaller and the larger values.

[0088] As used herein, the singular forms "a", "an", and "the" include the plural unless the context clearly dictates otherwise. Further, amounts, concentrations, or other values or parameters When a meter is given as any of a range, a preferred range, or a list of upper and lower preferred values, this is to be understood as specifically disclosing all ranges formed from any pair of any upper range limit or preferred value and any lower range limit or preferred value, regardless of whether the ranges are disclosed separately. When numerical ranges are recited in this specification, unless otherwise specified, the ranges are intended to include their endpoints, as well as all integers and fractional parts within the ranges. It is not intended that the scope of the present disclosure be limited to the specific values recited when defining the ranges.

[0089]

[0087] As used herein, the phrase "within any range defined between any two of the above values" literally means that any range may be selected from any two of the values recited prior to such phrase, regardless of whether the value is the lesser or the greater of the recited items. For example, a pair of values may be selected from the two lesser values, the two greater values, or the lesser and the greater values.

[0090]

[0088] It should be understood that the foregoing specification is merely illustrative of the present disclosure. Various alternative and modified forms may be devised by those skilled in the art without departing from the present disclosure. Accordingly, the present disclosure is intended to embrace all such alternative, modified, and changed forms that fall within the scope of the appended claims.

Claims

1. A composition comprising an azeotrope or azeotrope-like composition consisting essentially of 61 wt. % to 99 wt. % 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and 1 wt. % to 39 wt. % water, wherein the azeotrope or azeotrope-like composition has a boiling point of 13.5°C to 14.5°C at a pressure of 12.5 psia to 16.5 psia.

2. The azeotrope or azeotrope-like composition is 2. The composition of claim 1, consisting essentially of 61 wt. % to 90 wt. % 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and 10 wt. % to 39 wt. % water.

3. The azeotrope or azeotrope-like composition is 3. The composition of claim 2, consisting essentially of 61.39 wt.% to 88.29 wt.% 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and 11.71 wt.% to 38.61 wt.% water.

4. 4. The composition of any of claims 1 to 3, wherein the azeotrope or azeotrope-like composition has a boiling point of 13.99°C to 14.02°C at a pressure of 14.5 psia.

5. 5. A method of forming the azeotrope or azeotrope-like composition of any of claims 1 to 4, comprising combining 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water to form the azeotrope or azeotrope-like composition.

6. A method for separating at least one other substance from 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) from a composition comprising 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and at least one other substance, comprising: providing a composition comprising 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and at least one other substance; subjecting the composition to conditions effective to vary the relative amounts of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water and to form an azeotrope or azeotrope-like composition according to any one of claims 1 to 4; separating the azeotrope or azeotrope-like composition from 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb); A method comprising:

7. Varying the relative amounts of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water adding 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) to the composition; or adding water to the composition; or adding both 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water to the composition. The method of claim 6, comprising:

8. The method of claim 6 or 7, wherein the at least one other substance comprises 2,3,3,3-tetrafluoropropene (HFO-1234yf).

9. The method of claim 8, wherein the separating step includes at least one of phase separation, distillation, and fractionation.

10. 10. A method for producing 2,3,3,3-tetrafluoropropene (HFO-1234yf), comprising the step of converting at least a portion of the 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) present in the azeotrope or azeotrope-like composition of any one of claims 1 to 4 to 2,3,3,3-tetrafluoropropene (HFO-1234yf).

11. 11. The method of claim 10, wherein the step of converting at least a portion of the 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) to 2,3,3,3-tetrafluoropropene (HFO-1234yf) comprises reacting 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) with a base.

12. 12. The method of claim 11, wherein the base is a caustic base.

13. 13. The method of claim 12, wherein the base is an alkali metal hydroxide.

14. 14. The method of claim 13, wherein the base is KOH or NaOH.

15. 15. The method of any one of claims 10 to 14, wherein the step of converting 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) to 2,3,3,3-tetrafluoropropene (HFO-1234yf) is carried out in an aqueous environment.

16. The method of claim 15, wherein the conversion is carried out in the presence of a phase transfer catalyst.

17. The method of claim 16, wherein the conversion is carried out in the presence of ammonium halide.

18. The method of claim 17, wherein the conversion is carried out in the presence of a trialkylammonium halide or a tetraalkylammonium halide.

19. The method of claim 18, wherein the conversion is carried out in the presence of a trialkylammonium chloride or a tetraalkylammonium chloride.

20. 20. The method of any one of claims 10 to 19, wherein the step of converting 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) to 2,3,3,3-tetrafluoropropene (HFO-1234yf) is carried out at a temperature of from 0°C to 100°C.

21. The method of claim 20, wherein the conversion is carried out at a temperature of 20°C to 90°C.

22. The method of claim 21, wherein the conversion is carried out at a temperature of 50°C to 90°C.

23. The method of claim 22, wherein the conversion is carried out at a temperature of 60°C to 80°C.

24. 24. The process of any one of claims 10 to 23, wherein the azeotrope or azeotrope-like composition is present in a recycle line that transfers 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) to a reaction that converts 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) to 2,3,3,3-tetrafluoropropene (HFO-1234yf).

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