Azeotrope or azeotrope-like composition of 2-chloro-1, 1, 1, 2-tetrafluoropropane and water

Abstract

The present invention discloses an azeotrope or azeotrope-like composition of 2-chloro-1, 1, 1, 2-tetrafluoropropane and water, and a method for preparing the azeotrope or azeotrope-like composition. A heterogeneous azeotrope or azeotrope-like composition comprising 2-chloro-1, 1, 1, 2-tetrafluoropropane (HCFC-244bb) and water may comprise from about 0.05% by weight to about 92.01% by weight of 2-chloro-1, 1, 1, 2-tetrafluoropropane (HCFC-244bb) and from about 7.99% by weight to about 99.95% by weight of water, and have a boiling point of from about 13.5 DEG C to about 14.5 DEG C at a pressure of from about 12.5 psia to about 16.5 psia. The azeotrope or azeotrope-like composition may be used to separate 2-chloro-1, 1, 1, 2-tetrafluoropropane (HCFC-244bb) from impurities, and may be used to separate 2-chloro-1, 1, 1, 2-tetrafluoropropane (HCFC-244bb) from impurities.

Description

[0001] This application is a divisional application of the invention application with the application number "202011229801.7" and the invention name "Azeotropic or azeotrope-like composition of 2-chloro-1,1,1,2-tetrafluoropropane and water". Technical Field

[0002] The present disclosure relates to azeotropic or azeotrope-like compositions, and particularly to azeotropic or azeotrope-like compositions comprising an effective amount of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water. Background Art

[0003] Hydrofluoroolefins (HFOs), such as tetrafluoropropene, including 2,3,3,3-tetrafluoropropene (HFO-1234yf), are known to be effective refrigerants, heat transfer media, propellants, foaming agents, blowing agents, gaseous dielectrics, sterilant carriers, polymerization media, particle removal fluids, carrier fluids, polishing abrasives, displacement desiccants, and working fluids for power cycles. Unlike chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs), both of which can damage the Earth's ozone layer, HFOs pose no threat to the ozone layer. HFO-1234yf has also been shown to be a low global warming compound with low toxicity and can thus meet the increasingly stringent requirements for refrigerants in automotive air conditioners. Accordingly, compositions containing HFO-1234yf are materials that are being developed for many of the above applications.

[0004] One method for preparing HFO-1234yf uses 1,1,2,3-tetrachloropropene (HCFC-1230xa) as a starting material. The method comprises the following three steps: Step (1) In a gas-phase reactor equipped with a solid catalyst, 1230xa + 3 HF -> 2-chloro-3,3,3-trifluoropropene (1233xf) + 3HCl; Step (2) In a liquid-phase reactor equipped with a liquid catalyst, 1233xf + HF -> 2-chloro-1,1,1,2-tetrafluoropropane (244bb); and Step (3) In a liquid phase or in a gas-phase reactor, 244 bb -> 1234yf + HCl.

[0005] During the course of the above method, by-products may be produced and / or impurities may be present. It is desirable for all reactants and intermediate products to be in as pure a form as possible to limit unwanted side reactions. Accordingly, methods for reducing impurities in reactants and intermediate products are needed. Summary of the Invention

[0006] The present disclosure provides an azeotropic or azeotrope-like composition of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water.

[0007] It is well known in the art that it is impossible to predict the formation of an azeotrope, and the inventors have unexpectedly found that 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water form an azeotropic or azeotrope-like composition, particularly a heterogeneous azeotropic or azeotrope-like composition.

[0008] The present disclosure provides a composition comprising an azeotropic or azeotrope-like composition consisting essentially of an effective amount of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water, wherein the azeotropic or 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.

[0009] The azeotropic or azeotrope-like composition may consist 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 azeotropic or azeotrope-like composition may consist essentially of about 61 wt% to about 90 wt% of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and about 10 wt% to about 39 wt% of water; or about 61.39 wt% to about 88.29 wt% of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and about 11.71 wt% to about 38.61 wt% of water.

[0010] The present disclosure also provides a method for forming an azeotropic or azeotrope-like composition, the method comprising the step of combining 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water to form an azeotropic 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 about 13.5 °C to about 14.5 °C at a pressure of about 12.5 psia to about 16.5 psia.

[0011] The present disclosure also provides a method for separating impurities from a composition comprising 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and at least one impurity, comprising the steps of: providing 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 composition that consists essentially of or consists of an effective amount of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water; and separating the azeotropic or azeotrope-like composition from the composition comprising 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb), wherein the separating step can include at least one of phase separation, distillation, and fractionation. As used herein, "impurity" (and "impurities") encompasses substances intended to be separated from 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb), although the substance to be separated may itself still have value. An example of such an "impurity" is 2,3,3,3-tetrafluoropropene (HFO-1234yf), which is a very valuable commercial product that can be sold for revenue. The reference to "other substances" rather than "impurities" in the claims is to emphasize this point, and the terms "other substances" and "impurities" are intended to be used interchangeably in the present disclosure herein.

[0012] In the foregoing method, the step of changing the relative amounts of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water can include adding 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) to the composition, adding water to the composition, or adding 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water to the composition.

[0013] The present disclosure also provides a process for producing 2,3,3,3 - tetrafluoropropene (HFO - 1234yf), which comprises converting at least some of 2 - chloro - 1,1,1,2 - tetrafluoropropane (HCFC - 244bb) present in the azeotrope or azeotrope - like composition as defined above into 2,3,3,3 - tetrafluoropropene (HFO - 1234yf). The process includes direct conversion (wherein HCFC - 244bb is present in the azeotrope under conditions for conversion into HFO - 1234yf) and indirect conversion (for example, HCFC - 244bb previously present in the azeotrope or azeotrope - like composition is not part of the azeotrope or azeotrope - like composition under conditions for conversion into HFO - 1234yf). The latter possibility includes, for example, converting HCFC - 244bb into HFO - 1234yf in a reaction mixture that does not contain the azeotrope / azeotrope - like composition of the present disclosure because of the presence of other substances that disrupt the azeotrope, but wherein the molecules of HCFC - 244bb were previously in the form of the azeotrope / azeotrope - like composition. The process can include reacting HCFC - 244bb with a base, wherein the base can be a caustic base, preferably an alkali metal hydroxide, preferably KOH or NaOH. The reaction can be carried out in an aqueous environment, preferably in the presence of a phase - transfer catalyst, which is preferably an ammonium halide, preferably a trialkylammonium halide or a tetraalkylammonium halide, preferably a trialkylammonium chloride or a tetraalkylammonium chloride. The conversion of 2 - chloro - 1,1,1,2 - tetrafluoropropane (HCFC - 244bb) into 2,3,3,3 - tetrafluoropropene (HFO - 1234yf) can preferably be carried out at a temperature of from about 0 °C to about 100 °C, preferably from about 20 °C to about 90 °C, preferably from about 50 °C to about 90 °C, preferably from about 60 °C to about 80 °C. The conversion of 2 - chloro - 1,1,1,2 - tetrafluoropropane (HCFC - 244bb) into 2,3,3,3 - tetrafluoropropene (HFO - 1234yf) can suitably be carried out at super - atmospheric pressure, atmospheric pressure or sub - atmospheric pressure.

[0014] The present application discloses the following technical solutions.

[0015] Solution 1. A composition comprising an azeotrope or azeotrope - like composition consisting 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.

[0016] Solution 2. The composition according to Solution 1, wherein the azeotrope or azeotrope - like composition consists 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; More preferably, from 61.39% to about 88.29% by weight of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and from about 11.71% to about 38.61% by weight of water.

[0017] Embodiment 3. The composition according to Embodiment 1 or Embodiment 2, wherein the azeotropic or azeotrope-like composition 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.

[0018] Embodiment 4. A method of forming an azeotropic or azeotrope-like composition as described in any of the preceding embodiments, comprising the step of combining 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water to form the azeotropic or azeotrope-like composition.

[0019] Embodiment 5. A method of 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 the steps of: providing a composition comprising 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and at least one other substance; 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 composition, the 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, preferably forming the azeotropic or azeotrope-like composition described in any of Embodiments 1-3; and separating the azeotropic or azeotrope-like composition from the 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb).

[0020] Embodiment 6. The method according to Embodiment 5, wherein the step of changing the relative amounts of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water comprises: adding 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) to the composition; or adding water to the composition; or adding 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water to the composition.

[0021] Embodiment 7. The method according to Embodiment 5 or Embodiment 6, wherein the at least one other substance comprises 2,3,3,3-tetrafluoropropene (HFO-1234yf), preferably wherein the separation step comprises at least one of phase separation, distillation, and fractionation.

[0022] Embodiment 8. A method for preparing 2,3,3,3-tetrafluoropropene (HFO-1234yf), comprising converting at least some of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) present in the azeotrope or azeotrope-like composition according to any one of Embodiments 1-3 into 2,3,3,3-tetrafluoropropene (HFO-1234yf).

[0023] Embodiment 9. The method according to Embodiment 8, wherein converting at least some of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) into 2,3,3,3-tetrafluoropropene (HFO-1234yf) comprises reacting 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) with a base.

[0024] Embodiment 10. The method according to Embodiment 9, wherein the base is a caustic base, preferably an alkali metal hydroxide, preferably KOH or NaOH.

[0025] Embodiment 11. The method according to any one of Embodiments 8-10, wherein converting 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) into 2,3,3,3-tetrafluoropropene (HFO-1234yf) is 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.

[0026] Embodiment 12. The method according to any one of Embodiments 8-11, wherein converting 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) into 2,3,3,3-tetrafluoropropene (HFO-1234yf) is 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.

[0027] Embodiment 13. The method according to any one of Embodiments 8-12, 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 the reaction for converting 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) into 2,3,3,3-tetrafluoropropene (HFO-1234yf). Description of the Drawings

[0028] Figure 1 This is a graph of boiling point vs. percentage of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) in water. Detailed implementation mode

[0029] 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) are reacted with anhydrous hydrogen fluoride (HF) in a first gas-phase reactor (fluorination reactor) to produce a mixture containing at least HCFO-1233xf (2-chloro-3,3,3-trifluoropropene) and HCl. The reaction can be carried out at a temperature of about 200 °C to about 400 °C and a pressure of about 0 psig to about 200 psig. The effluent stream leaving the gas-phase reactor may optionally contain additional 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.

[0030] The reaction can be carried out in any reactor suitable for gas-phase fluorination reactions. The reactor can be made of materials resistant to the corrosive action of hydrogen fluoride and the catalyst, such as Hastelloy ® , Inconel ® , Monel ® , etc. In the case of a gas-phase process, the reactor is filled with a gas-phase fluorination catalyst. Any fluorination catalyst known in the art can be used in this process. Suitable catalysts include, but are not limited to, oxides, hydroxides, halides, oxyhalides, inorganic salts thereof, and mixtures of chromium, aluminum, cobalt, manganese, nickel, and iron, any of which can optionally be halogenated. The set of catalysts suitable for the present invention non-exclusively includes Cr2O3, FeCl3 / C, Cr2O3 / Al2O3, Cr2O3 / AlF3, Cr2O3 / carbon, CoCl2 / Cr2O3 / Al2O3, NiCl2 / Cr2O3 / Al2O3, CoCl2 / AlF3, NiCl2 / AlF3, and mixtures thereof. The chromium oxide / aluminum oxide catalyst is described in U.S. Patent 5,155,082, the content of which is incorporated herein by reference. Chromium(III) oxide, such as crystalline chromium oxide or amorphous chromium oxide, is preferred, and amorphous chromium oxide is most preferred. Chromium oxide (Cr2O3) is a commercially available material that can be purchased in various particle sizes. A fluorination catalyst with a purity of at least 98% is preferred. The fluorination catalyst is present in excess, but at least in an amount sufficient to drive the reaction.

[0031] 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 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 between HF and the compound of Formula I, II or III is carried out at about 200 °C to about 600 °C; in another embodiment, at about 200 °C to about 400 °C; in another embodiment, at a temperature of about 200 °C to about 300 °C. In one embodiment, the reaction pressure is about 0 psig to about 500 psig; about 20 psig to about 200 psig in another embodiment; and about 50 psig to about 100 psig in a further embodiment.

[0032] For example, when the compound of Formula I is 1230xa, in one embodiment, the molar ratio of HF to 1230xa in the reaction Step 1 is about 1:1 to about 50:1; 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 between HF and 1230xa is carried out at about 200 °C to about 600 °C; in another embodiment, at about 200 °C to about 400 °C; in another embodiment, at a temperature of about 200 °C to about 300 °C. In one embodiment, the reaction pressure is about 0 psig to about 500 psig; about 20 psig to about 200 psig in another embodiment; and about 50 psig to about 100 psig in a further embodiment.

[0033] Similarly, when the compound of Formula II is 2,3,3,3-tetrachloro-1-propene (HCC-1230xf or 1230xf), in one embodiment, the molar ratio of HF to 1230xf in the reaction Step 1 is about 1:1 to about 50:1; about 10:1 to about 50:1 in another embodiment; and about 10:1 to about 20:1 in yet a further embodiment. In one embodiment, the reaction between HF and 1230xf is carried out at about 200 °C to about 600 °C; in another embodiment, at about 200 °C to about 400 °C; and in another embodiment, at a temperature of about 200 °C to about 300 °C. In one embodiment, the reaction pressure is about 0 psig to about 500 psig; about 20 psig to about 200 psig in another embodiment; and about 50 psig to about 100 psig in another embodiment.

[0034] 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 reaction step 1 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. In one embodiment, the reaction between HF and 240db is carried out at from about 200 °C to about 600 °C; in another embodiment, from about 200 °C to about 400 °C, and in another embodiment, at a temperature from about 200 °C to about 300 °C. In one embodiment the reaction pressure is 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 psig to about 100 psig.

[0035] The first step of the reaction need not be limited to a gas phase reaction as described above, but can also be carried out using a liquid phase reaction or a combination of liquid and gas phases, such as that disclosed in US Published Patent Application 20070197842, the contents of which are incorporated herein by reference. It is also contemplated that the reaction can be carried out batchwise, continuously or in a combination of these. For embodiments in which the reaction comprises a liquid phase reaction, the reaction can be catalytic or non-catalytic. Lewis acid catalysts can be used, such as metal halide catalysts, including antimony halides, tin halides, thallium halides, iron halides and combinations of two or more of these. In certain embodiments, metal chlorides and metal fluorides are used, including but not limited to SbCl5, SbCl3, SbF5, SnCl4, TiCl4, FeCl3 and combinations of two or more of these.

[0036] The fluorination reaction can be carried out to obtain a single pass or multi-pass conversion of at least 1% or higher, 5% or higher, 10% or higher or about 20% or higher. In certain preferred embodiments of the present invention, the starting reactants are converted to 1233xf in a single pass, where the reaction conditions achieve a conversion of greater than 75%; in one embodiment, greater than 85%; in another embodiment, greater than 95%; and in another embodiment, greater than 99%. In view of this, the resulting effluent contains little or trace amounts of unreacted starting materials, or can be substantially free of such compounds.

[0037] The effluent from the fluorination reaction step (step 1), including any intermediate effluents that may be present in a multi-stage reactor configuration, is processed to achieve the desired degree of separation. For example, in embodiments where the reactor effluent contains 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf), the effluent will typically also contain HCl, unreacted HF, and trace amounts (if any) of unreacted starting components (e.g., 1230xa, 1230xf, and / or 240db). The effluent may also contain one or more byproduct organics, 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) and 1,1,1,2,2-pentafluoropropane (245cb) and HFO-1234yf and combinations thereof. In further embodiments, the impurity is hydrogen fluoride. Other byproduct organics may also include but are not limited to dichlorotrifluoropropane (243) isomers and trichlorodifluoropropane (242) isomers, as well as dimers derived from one or more starting compounds. As non-limiting examples, dimers derived from 1230xa include but are not limited to C6H3F6Cl, C6H3F7Cl2, C6F6Cl2, C6H8Cl2, C6F5Cl3, C6H3F2Cl5, etc.

[0038] After removing HCl by distillation and removing a portion of HF by phase separation, water is added in an effective amount to the remaining effluent from step 1 to form an azeotrope or azeotrope-like mixture containing 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) and water, and then the azeotrope or azeotrope-like mixture can be separated from the effluent (with its impurities) by the techniques described herein. Then 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) is separated from water as described herein, and then 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) is fed to the hydrofluorination reactor of step 2 discussed below.

[0039] In step 2 of the above-described process for forming 2,3,3,3-tetrafluoroprop-1-ene, 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 can be carried out in the liquid phase in a liquid-phase reactor, which can be lined with TFE or PFA. Such a process can be carried out in a temperature range of about 70 °C to about 120 °C and at a pressure of about 50 psig to about 120 psig.

[0040] Any liquid-phase fluorination catalyst can 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, chromium fluoride halides, chromium fluoride oxides, or combinations thereof. Specific non-exclusive examples of liquid-phase fluorination catalysts are SbCl5, SbCl3, SbF5, SnCl4, TaCl5, TiCl4, NbCl5, MoCl6, FeCl3, fluoride classes of SbCl5, fluoride classes of SbCl3, fluoride classes of SnCl4, fluoride classes of TaCl5, fluoride classes of TiCl4, fluoride classes of NbCl5, fluoride classes of MoCl6, fluoride classes of FeCl3, or combinations thereof. Antimony pentachloride is most preferred.

[0041] If the catalyst becomes deactivated, it can be easily regenerated by any means known in the art. A suitable method for regenerating the catalyst includes passing a chlorine stream over the catalyst. For example, for each pound of the liquid-phase fluorination catalyst, about 0.002 pounds to about 0.2 pounds of chlorine per hour can be added to the liquid-phase reaction. This can be carried out, for example, at a temperature of about 65 °C to about 100 °C for about 1 hour to about 2 hours or continuously.

[0042] The reaction step 2 in which the 244bb product is formed does not have to be limited to a liquid-phase reaction, but can also be carried out using a gas-phase reaction or a combination of liquid-phase and gas-phase, as disclosed in, for example, U.S. Published Patent Application 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 can include standard gas-phase reagents for such reactions, and the fluorinating agent can include those commonly known in the art, such as, but not limited to, hydrogen fluoride.

[0043] The effluent from the hydrofluorination reaction step (step 2) is treated to achieve the desired separation and / or other treatments, and the effluent is mainly composed of 244bb and HF (plus a small amount of unreacted 2-chloro-3,3,3-trifluoropropylene (HCFO-1233xf), perfluorinated byproducts 245cb, HCl and Cl2). For example, the product stream is fed to a light-removal tower, where a stream consisting mainly of 245cb, HCl and Cl2 leaves the top of the tower and is sent to a thermal oxidizer (T-OX) for destruction. In one embodiment, water is added to the bottom stream of the light-removal tower consisting mainly of 244bb and HF (plus a small amount of unreacted 1233xf) to form an azeotrope or azeotrope-like mixture comprising 1233xf and water. In one embodiment, 244bb is not present in the mixture, in which case 1233xf is separated from water by techniques known in the art described above, such as by distillation. In another embodiment, 244bb is also present in an azeotrope or azeotrope-like mixture comprising 1233xf and water. 244bb is then separated from 1233xf by techniques known in the art (e.g., as described in U.S. Pat. No. 8,252,965, the contents of which are incorporated by reference). The separated 1233xf can be recycled back to the hydrofluorination reactor of step 2 as described above.

[0044] Step 3 of the method can be carried out in the gas phase or in the liquid phase. When HFO-1234yf is produced in the gas phase, 244bb is fed to a second gas phase reactor (dehydrochlorination reactor) for dehydrochlorination to produce the desired product 2,3,3,3-tetrafluoroprop-1-ene (1234yf). The reactor may optionally contain a catalyst that can catalytically dehydrochlorinate HCFC-244bb to produce HFO-1234yf; however, in one embodiment, the reactor contains the catalyst.

[0045] The catalyst may be a metal halide, a halogenated metal oxide, a neutral (or 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 metal includes, but is not limited to, Cr 3+ , Fe 3+ Mg 2+ , Ca 2+ 、Ni 2+ 、Zn 2+ , Pd 2+ , Li + 、Na + , K + and Cs +The component halogen includes, but is 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 can include those known in any prior art, particularly those using HF, F2, HCl, Cl2, HBr, Br2, HI, and I2 as halogen sources.

[0046] In one aspect, neutral metals are used, i.e., zero-valent metals, metal alloys, and mixtures thereof. Useful metals include, but are not limited to, Pd, Pt, Rh, Fe, Co, Ni, Cu, Mo, Cr, Mn, and combinations of the above metals as alloys or mixtures. The catalyst can be loaded or unloaded. Useful examples of metal alloys include, but are not limited to, SS 316, Monel ® 400, Incoloy ® 825, Inconel ® 600, and Inconel ® 625. Such catalysts can be provided as discrete loaded or unloaded elements and / or as part of a reactor and / or reactor wall.

[0047] Exemplary but non-limiting catalysts include activated carbon, stainless steel (such as SS 316), austenitic nickel-based alloys (such as Inconel ® 625), nickel, fluorinated 10% CsCl / MgO, and 10% CsCl / MgF2, etc. In one embodiment, the reaction temperature is about 300 °C to about 550 °C, and the reaction pressure can be about 0 psig to about 150 psig. The reactor effluent can be fed to an alkali scrubber or distillation column to remove HCl by-products to produce an acid-free organic product, which can optionally be further purified using one or any combination of purification techniques known in the art.

[0048] Step 3 can also be carried out 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 dehydrochlorinating 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) using a base. The base can be a caustic base, preferably selected from alkali metal hydroxides, alkali metal oxides, alkaline earth metal hydroxides, alkaline earth metal oxides, and combinations thereof. Preferred examples of the caustic base are KOH, NaOH, LiOH, Mg(OH)2, Ca(OH)2, CaO, and combinations thereof. The caustic base can be added to the reaction in solid form or as a solution. When provided as a solution, the preferred solvent is water or an alcohol, preferably MeOH or EtOH. KOH is particularly preferred and is preferably provided as an aqueous solution, preferably containing from about 5 wt% to about 62 wt% KOH, preferably 5 wt% to 55 wt% KOH. The dehydrochlorination in the liquid phase is preferably carried out in an aqueous environment. In the case of the liquid phase Step 3, the aqueous environment is one in which the liquid phase reaction mixture contains from 5 wt% to 80 wt% water, preferably 10 wt% to 60 wt% water, more preferably 20 wt% to 40 wt% water. It is also preferred to use a phase transfer catalyst, especially when the reaction is carried out in an aqueous environment, as it is believed to assist the reactivity by promoting close contact between the base and 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb). Such phase transfer catalysts can include, but are not limited to, crown ethers (e.g., 18-crown-6), onium salts (e.g., phosphonium salts or ammonium salts having a halogen anion), cryptands (e.g., N[CH2CH2OCH2CH2OCH2CH2]3N), polyalkylene glycols (e.g., poly(ethylene glycol)), their derivatives, and combinations thereof. In one embodiment, the phase transfer catalyst is Aliquat 336. Onium salts are preferred, especially ammonium salts. The ammonium salt is preferably an ammonium halide, preferably a trialkylammonium halide or a tetraalkylammonium halide, preferably a trialkylammonium chloride or a tetraalkylammonium chloride.

[0049] The liquid phase variant of Step 3 is preferably carried out at a temperature of from about 0 °C to about 100 °C, preferably from about 20 °C to about 90 °C, preferably from about 50 °C to about 90 °C, preferably from 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) can suitably be carried out at superatmospheric pressure, atmospheric pressure, or subatmospheric pressure. These temperatures and pressures are particularly useful when using a base in the liquid phase as described above for Step 3.

[0050] WO-2011 / 139646 discloses further experimental details of the conversion of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) to 2,3,3,3-tetrafluoropropene (HFO-1234yf) in the liquid phase, the content of which is incorporated herein by reference.

[0051] An alternative method for preparing HFO-1234yf uses 1,2-dichloro-3,3,3-trifluoropropane (HCFC-243db) as a starting material and is carried out in the gas phase and the liquid phase. In this alternative method, the method comprises the following three steps (where steps (2) and (3) are the same as those described 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 with a phase transfer catalyst, and / or a solvent and / or a salt); Step (2): 1233xf + HF → 244bb in a liquid-phase reactor equipped with a liquid hydrogen fluoride catalyst; and Step (3): 244bb → 1234yf + HCl in a gas-phase reactor (with or without a catalyst) or in the liquid phase.

[0052] In the alternative method, where the starting composition comprises 243db, 243db is dehydrohalogenated to produce a product mixture containing 1233xf. When the starting composition comprises 243db, the dehydrohalogenation reaction is a dehydrochlorination reaction. The dehydrochlorination reaction is carried out in a reaction zone and can occur in the gas phase using a catalyst or can occur in the liquid phase using a base and an optional phase transfer catalyst and / or a solvent and / or a salt. For example, WO 2012 / 115934 discloses a gas-phase reaction of 243db with a carbon catalyst. WO 2012 / 115938 discloses a gas-phase reaction of 243db with a chromium oxyfluoride catalyst. WO 2017 / 044719 discloses a reaction of 243db with a fluorinated alkane in the presence of a fluorination catalyst to prepare 1233xf and other compounds that can be used to prepare 1234yf. WO 2017 / 044724 discloses a liquid-phase reaction of 243db with caustic. If the dehydrochlorination reaction is carried out in the gas phase, HCl is produced. On the other hand, when the dehydrochlorination reaction is carried out in the liquid phase, no HCl is produced. When starting with a compound having formula (III), other methods can be used, as would be known to those skilled in the art.

[0053] For embodiments where anhydrous and impurity-free conditions are desired during 1234yf synthesis, the reactants and intermediate products can be purified. For example, it is desirable to remove impurities from 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf).

[0054] It has been found that 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water form heterogeneous azeotropic and azeotrope-like compositions or mixtures, and the present disclosure provides a heterogeneous azeotropic or azeotrope-like composition comprising 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water. The azeotropic or azeotrope-like composition can consist essentially of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water, or the azeotropic or azeotrope-like composition can consist of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water.

[0055] The inventors have experimentally found that 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water form an azeotropic or azeotrope-like composition.

[0056] A heterogeneous azeotrope consists of two liquid phases and one gas phase all in equilibrium. For a heterogeneous azeotrope at a given temperature and pressure, the composition of each of the two liquid phases and the composition of the gas phase remain constant. If a heterogeneous azeotrope forms, then at constant pressure, the boiling point of the heterogeneous azeotrope will be lower than that of the lower-boiling component ("minimum-boiling azeotrope").

[0057] An "azeotropic" (or "azeotrope") composition is a unique combination of two or more components. An azeotrope can be homogeneous (which has one liquid phase) or heterogeneous (which has two liquid phases). An azeotropic composition can be characterized in various ways. For example, at a given pressure, an azeotropic composition boils at a constant characteristic temperature that is higher than the higher-boiling component (maximum-boiling azeotrope) or lower than the lower-boiling component (minimum-boiling azeotrope). However, in the case of a heterogeneous azeotrope, the boiling point of the azeotrope will always be lower than the boiling point of the lower-boiling component. At this characteristic temperature, a homogeneous azeotrope has the same composition in both the gas phase and the liquid phase. In the case of a heterogeneous azeotrope, then at this characteristic temperature, the composition of each of the two liquid phases and the gas phase will remain constant during boiling. An azeotropic composition does not fractionate upon boiling or evaporation. Thus, the components of an azeotropic composition cannot be separated during a phase change.

[0058] A homogeneous azeotropic composition is also characterized in that at the characteristic azeotropic temperature, the bubble point pressure of the liquid phase is the same as the dew point pressure of the gas phase. The behavior of an azeotropic composition is contrary to that of a non-azeotropic composition, where during boiling or evaporation, the liquid composition of a non-azeotropic composition changes to a significant degree.

[0059] However, those of ordinary skill in the art will understand that at different pressures, both the composition and the boiling point of the azeotropic composition will vary to some extent. Thus, depending on the temperature and / or pressure, the azeotropic composition can have a variable composition. Accordingly, those skilled in the art will understand that a composition range rather than a fixed composition can be used to define the azeotropic composition. In addition, an azeotrope can be defined by the exact weight percentage of each component of a composition characterized by a fixed boiling point at a specified pressure.

[0060] An “azeotrope-like” composition is a composition of two or more components that behaves substantially the same as an azeotropic composition. Thus, for the purposes of this disclosure, an azeotrope-like composition is a combination of two or more different components that, when in liquid form under a given pressure and in the case of a homogeneous azeotrope, will boil at a substantially constant temperature and will provide a vapor composition that is substantially the same as the liquid composition undergoing boiling. In the case of a heterogeneous azeotrope, two liquid phases will form under a given pressure, and the two liquid phases will be covered by the vapor composition. Each of the two liquid phases and the gas phase will remain substantially constant during boiling.

[0061] For the purposes of this disclosure, an azeotrope-like composition is a composition or composition range that boils in the temperature range of about 12.0 °C to 13.6 °C at a pressure of about 12.5 psia to about 16.5 psia.

[0062] Azeotropic or azeotrope-like compositions can be identified using many different methods.

[0063] For the purposes of this disclosure, the azeotropic or 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 an extremely accurate measurement of the boiling point of a liquid by measuring the temperature of the vapor-liquid equilibrium.

[0064] The boiling point of each component alone is measured at a constant pressure. As those skilled in the art will understand, for a binary azeotropic or azeotrope-like composition, initially the boiling point of one component of the composition is measured. Then the second component of the composition is added in different amounts, and the boiling point of each resulting composition is measured using the ebulliometer at the constant pressure. In the case of a ternary azeotrope, the initial composition will contain a binary blend, and the third component is added in different amounts. The boiling point of each resulting ternary composition is measured using the ebulliometer at the constant pressure.

[0065] Plot the measured boiling point versus the composition of the test composition, e.g., for a binary azeotrope, versus the amount of the second component added to the composition (expressed as weight % or mole %). The presence of an azeotropic composition can be identified by observing the highest or lowest boiling temperature above or below the boiling points of any of the individual components.

[0066] As will be understood by those skilled in the art, the identification of an azeotropic or azeotrope-like composition is carried out by comparing the change in the boiling point of the composition relative to the boiling point of the first component when the second component is added to the first component. Thus, it is not necessary to calibrate the system to the reported boiling point of a specific component in order to measure the change in boiling point.

[0067] As previously mentioned, at the maximum or minimum boiling point, the composition of the gas phase is the same as the composition of the liquid phase. Thus, an azeotrope-like composition is a composition of components that provides a substantially constant minimum or maximum boiling point, which is 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, at which substantially constant boiling point, the composition of the gas phase is substantially the same as the composition of the liquid phase.

[0068] The present disclosure provides an azeotropic or azeotrope-like composition comprising an effective amount of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water to form an azeotropic or azeotrope-like composition. As used herein, the term "effective amount" is the amount of each component that forms an azeotropic or azeotrope-like composition when combined with the other component.

[0069] The azeotropic or azeotrope-like composition of the present invention can consist essentially of, or consist of, a combination of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water.

[0070] As used herein, the term "consisting essentially of" with respect to the components of an azeotropic or azeotrope-like composition or mixture means that the composition contains the designated components in an azeotropic or azeotrope-like ratio and can 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 is those that form a binary azeotrope, which optionally can 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 order azeotrope).

[0071] The present disclosure also provides a method for forming an azeotropic or azeotrope-like composition by mixing, combining, or blending an effective amount of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water. Any of the various methods known in the art for combining two or more components to form a composition can be used in the method of the present invention. For example, 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water can be mixed, blended, or combined manually and / or by machine, as part of a batch or continuous reaction and / or process, or by a combination of two or more such steps. The components can be provided in the desired amounts, for example, by weighing and then combining the amounts.

[0072] The azeotropic or azeotrope-like composition can 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.

[0073] The present disclosure also provides a composition comprising the azeotropic or azeotrope-like composition. For example, a composition is provided that comprises at least about 14 wt% of the azeotropic or azeotrope-like composition, or at least about 21 wt% of the azeotropic or azeotrope-like composition, or at least about 25 wt% of the azeotropic or azeotrope-like composition, or at least about 70 wt% of the azeotropic or azeotrope-like composition, or at least about 90 wt% of the azeotropic or azeotrope-like composition, or at least 95 wt% of the azeotropic or azeotrope-like composition, or at least 99 wt% of the azeotropic or azeotrope-like composition.

[0074] The azeotropic or azeotrope-like composition disclosed herein that comprises an effective amount of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water, consists essentially of or consists of the same can be used to separate impurities from 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb).

[0075] The preparation of an azeotropic or azeotrope-like composition that comprises an effective amount of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water, consists essentially of or consists of the same allows separation techniques, such as azeotropic distillation, to be used to remove impurities from 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb).

[0076] In particular, 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 the same, can be formed from a composition comprising 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb), water, and at least one impurity. After forming the azeotropic or azeotrope-like composition, the azeotropic or azeotrope-like composition can be separated from other compounds by suitable methods, such as by distillation, phase separation, or fractionation.

[0077] In one example, the present disclosure provides a method for separating 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) from impurities, comprising the steps of: providing a primary composition of crude 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 subjecting the primary composition to conditions effective to form a secondary composition that is 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, and separating the secondary composition from the primary composition by a separation technique such as phase separation, distillation, or fractionation. Thereafter, the secondary composition can 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 can include adding 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) to the composition, adding water to the composition, or adding 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water to the composition.

[0078] 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 the same can be used to prepare 2,3,3,3-tetrafluoropropene (HFO-1234yf). For example, the azeotropic or azeotrope-like composition can be combined with other 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). Residual 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) present in the crude 2,3,3,3-tetrafluoropropene (HFO-1234yf) can be removed together with water in the form of the azeotropic or azeotrope-like composition of the present disclosure, wherein the removal can take the form of, for example, distillation, phase separation, or a combination thereof. The azeotropic or azeotrope-like composition removed from the crude product can be recycled back to step 3, especially when step 3 is carried out in the liquid phase.

[0079] Although not necessarily, an azeotropic or azeotrope-like composition may also form in the reaction for preparing 2,3,3,3-tetrafluoropropene (HFO-1234yf) from 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb). The presence of the azeotropic or azeotrope-like composition will depend on factors such as whether the azeotrope is disrupted by other substances present. Although not necessarily, examples of how likely an azeotropic or azeotrope-like composition may form include the following: l When water is present as a solvent in the reaction, such as when the reaction is carried out in an aqueous environment, such as when a base is used in an aqueous solution.

[0080] l When water is formed in the reaction. For example, in the presence or absence of water as a solvent, the dehydrochlorination of HCFC-244bb with hydroxide ions will form water molecules according to the following equation: CF3CFClCCH3 + - OH → CF3CF = CH2 + Cl - + H2O. Those skilled in the art will understand that water molecules can be formed when other types of bases are used, especially caustic bases.

[0081] The following non-limiting examples are used to illustrate the present invention. Examples

[0082] Example 1 - Vapor-Liquid Equilibrium (VLE) Study A boiling point meter consisting of a vacuum jacketed tube with a dry ice cooled condenser at the top was further equipped with a quartz thermometer. The boiling point meter was initially charged with 16.21 grams of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb). Water was then added incrementally and the boiling point temperature of the mixture was recorded. The results are shown in Table 1 and are shown inFigure 1 Shown in the figure.

[0083] Table 1 wt% HCFC-244bb wt% water Temperature (°C) 100.00 0.00 14.36 99.69 0.31 14.28 99.08 0.92 14.18 97.89 2.11 14.10 96.14 3.86 14.07 93.92 6.08 14.06 91.27 8.73 14.05 88.29 11.71 14.02 84.60 15.40 14.01 81.21 18.79 14.00 78.08 21.92 14.00 75.19 24.81 13.99 72.50 27.50 13.99 69.39 30.61 13.99 66.54 33.46 13.99 69.92 36.08 13.99 61.49 38.51 13.99

[0084] As shown, the boiling point temperature of the mixture reaches a minimum and then levels off, indicating the formation of a heterogeneous azeotrope. More specifically, the boiling point change of a composition containing from about 61% to about 99% by weight of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) is less than 0.2 °C. In addition, the boiling point change of a composition containing from about 66% to about 99% by weight of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) is less than 0.1 °C. The ambient pressure during the measurement was 14.49 psia.

[0085] 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 the formation of a heterogeneous azeotrope. The upper (water-rich) and lower (2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb)-rich) phases were separated and analyzed. The compositions of the two phases are shown in Table 2 below.

[0086] Table 2 Component Upper phase, wt% Lower phase, wt% HCFC-244bb 0.05% 92.01% Water 99.95% 7.99%

[0087] Example 3 - Purification of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) In this example, a composition is provided that contains 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and an impurity, which can be HF. An effective amount of water is added to the composition, and the composition is subjected to conditions effective to form an azeotrope 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. The azeotrope or azeotrope-like composition is then separated from the composition containing the major compound by separation techniques such as phase separation, distillation, and / or fractionation.

[0088] Example 4 - Separation of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) from hydrogen fluoride (HF) In this embodiment, a composition is provided that comprises the main compound 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb), and hydrogen fluoride (HF) as an impurity. An effective amount of water is added to the composition, and the composition is subjected to conditions effective to form an azeotrope 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. The azeotrope or azeotrope-like composition is then separated from the composition comprising the main compound by separation techniques such as phase separation, distillation, and / or fractionation.

[0089] Example 5 - Separation of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) from hydrogen fluoride (HF) In this embodiment, a composition is provided that comprises a main compound, such as 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb), and hydrogen fluoride (HF) as an impurity. 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 azeotrope 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. The azeotrope or azeotrope-like composition is then separated from the composition comprising the main compound by separation techniques such as phase separation, distillation, and / or fractionation.

[0090] Example 6 - Representative method for converting 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) to 2,3,3,3-tetrafluoropropene (HFO-1234yf) The dehydrochlorination of HCFC-244bb was carried out in a one-liter Parr reactor equipped with a thermocouple and a magnetic stirrer. 15 g of Aliquat 336™ was added to the reactor. The reactor was then closed and the pressure was tested. Then 294 g of the organic mixture and 270 g of 45% KOH were added to the reactor. GC analysis of the organic mixture showed 8.1 GC area % of 1234yf, 89.5 GC area % of 244bb, and 1.8 GC area % of 1233xf. The stirrer was then turned on and the reactor was heated to 55 °C. At 55 °C (after about 2 hours), the pressure in 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 contents of the reactor after completion of the reaction showed 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.

[0091] The above synthesis examples are included to illustrate the reaction and not as a comment on the presence of the claimed azeotrope or azeotrope-like composition in the synthesis process.

[0092] Example 7 - Representative Purification of HCFC-244bb Purify a composition comprising HCFC-244bb and water to provide a purified stream of HCFC-244bb.

[0093] Charge 1000 kg of a mixture comprising 920.1 kg of HCFC-244bb and 79.9 kg of water to the reboiler of a batch distillation system that includes a reboiler, a multi-stage rectification section containing dumped packing such as IMTP® packing available from Koch-Glitsch, and a condenser. Cool the condenser with flowing cold water at about 5 °C at the condenser inlet. The reboiler has a half-pipe jacket for steam. The reboiler charge can be the organic phase of a mixture of HCFC-244bb and water that has undergone phase separation, with the aqueous phase decanted from the top.

[0094] Distill the overhead stream of the azeotrope mainly containing HCFC-244bb and water using the batch distillation system, leaving substantially in the reboiler HCFC-244bb containing about 0.05 wt% water (see Table 3). It can be further dried by passing the material in the reboiler through a desiccant, such as 3A molecular sieve.

[0095] Table 3 Composition Reboiler charge (kg) Distillate (kg) Bottoms (kg) HCFC-244bb 920.1 190.0* 730.1 Water 79.9 79.5 0.4 Under these conditions, the azeotropic composition is 70 wt% HCFC-244bb. Substances slightly in excess of the azeotrope are recovered at the top.

[0096] Although this example shows purification in a batch distillation scheme, it can be modified by those skilled in the art to accommodate continuous distillation purification.

[0097] Aspect Aspect 1 is a composition comprising an azeotrope or azeotrope-like composition consisting essentially of an effective amount of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water.

[0098] Aspect 2 is the composition of aspect 1, wherein the azeotrope 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.

[0099] Aspect 3 is a composition of Aspect 1 or Aspect 2, wherein the azeotrope or azeotrope-like composition consists essentially of from about 0.05% to about 92.01% by weight of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and from about 7.99% to about 99.95% by weight of water.

[0100] Aspect 4 is a method of forming an azeotrope or azeotrope-like composition, comprising the step of combining 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water to form an azeotrope or azeotrope-like composition, the azeotrope 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.

[0101] Aspect 5 is the method of Aspect 4, wherein the combining step comprises combining from about 0.05% to about 99.95% by weight of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and from about 7.99% to about 99.95% by weight of water.

[0102] Aspect 6 is a method of separating impurities from a composition comprising 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and at least one impurity from 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb), comprising the steps of: providing 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 azeotrope or azeotrope-like composition, the azeotrope 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, and separating the azeotrope or azeotrope-like composition from the composition comprising 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb).

[0103] 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 comprises adding 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) to the composition.

[0104] 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 comprises adding water to the composition.

[0105] Aspect 9 is the method of any one of Aspects 6 - 8, wherein the step of changing the relative amounts of 2 - chloro - 1,1,1,2 - tetrafluoropropane (HCFC - 244bb) and water comprises adding 2 - chloro - 1,1,1,2 - tetrafluoropropane (HCFC - 244bb) and water to the composition.

[0106] Aspect 10 is the method of any one of Aspects 6 - 9, wherein the separating step comprises at least one of phase separation, distillation, and fractionation.

[0107] As used herein, the phrase "any range defined between any two of the foregoing values" literally means that any range may be selected from any two of the values listed prior to such phrase, regardless of whether the values are in the lower or higher part of the list. For example, a pair of values may be selected from two lower values, two higher values, or a lower value and a higher value.

[0108] Unless the context clearly indicates otherwise, the singular forms "a", "an", and "the" as used herein include the plural. Further, when an amount, concentration, or other value or parameter is given as a range, a preferred range, or a list of preferred upper and lower values, this is to be understood as specifically disclosing all ranges formed from any pair of any range upper limit or preferred value and any range lower limit or preferred value, regardless of whether the ranges are separately disclosed. When a numerical range is recited herein, unless otherwise stated, the range is intended to include its endpoints, as well as all integers and fractions within the range. When defining a range, the scope of the present disclosure is not intended to be limited to the specific values recited.

[0109] As used herein, the phrase "any range defined between any two of the foregoing values" literally means that any range may be selected from any two of the values listed prior to such phrase, regardless of whether the values are in the lower or higher part of the list. For example, a pair of values may be selected from two lower values, two higher values, or a lower value and a higher value.

[0110] It should be understood that the foregoing description is only illustrative of the present disclosure. Those skilled in the art can devise various alternatives and modifications without departing from the present disclosure. Accordingly, the present disclosure is intended to cover all such alternatives, modifications, and variations that fall within the scope of the appended claims.

Claims

1. A composition comprising an azeotropic or azeotrope-like composition consisting essentially of from about 0.05% to about 92.01% by weight of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and from about 7.99% to about 99.95% by weight of water.

2. The composition according to claim 1, wherein the azeotropic or azeotrope-like composition consists essentially of: from about 61% to about 90% by weight of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and from about 10% to about 39% by weight of water; more preferably from 61.39% to about 88.29% by weight of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and from about 11.71% to about 38.61% by weight of water.

3. The composition according to claim 1 or claim 2, wherein the azeotropic or azeotrope-like composition 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.

4. A method of forming an azeotropic or azeotrope-like composition as described in any of the preceding claims, comprising the step of combining 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water to form the azeotropic or azeotrope-like composition.

5. A method of 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 the steps of: providing a composition comprising 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and at least one other substance; 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 composition consisting essentially of or consisting of an effective amount of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and water, preferably forming the azeotropic or azeotrope-like composition described in any of claims 1-3; and separating the azeotropic or azeotrope-like composition from the 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb).

6. A method of preparing 2,3,3,3-tetrafluoropropene (HFO-1234yf), comprising converting at least some of the 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) present in the azeotropic or azeotrope-like composition described in any of claims 1-3 into 2,3,3,3-tetrafluoropropene (HFO-1234yf).

7. Use of HFO-1234yf as a refrigerant.

8. Use of HFO-1234yf as a propellant.

9. A method for manufacturing HFO-1234yf, comprising the following three steps: Step (1) In a gas-phase reactor equipped with a solid catalyst, 1230xa + 3 HF -> 2-chloro-3,3,3-trifluoropropene (1233xf) + 3HCl; Step (2) In a liquid-phase reactor equipped with a liquid catalyst, 1233xf + HF -> 2-chloro-1,1,1,2-tetrafluoropropane (244bb); and Step (3) In a liquid phase or in a gas-phase reactor, 244 bb -> 1234yf + HCl.

10. A method for converting at least some 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) into 2,3,3,3-tetrafluoropropene (HFO-1234yf), which comprises: reacting 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) with a base; wherein the reaction is carried out in an aqueous environment in the presence of a phase transfer catalyst; and wherein the reaction is carried out at a temperature of about 60 o °C - about 80 o °C.

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