Azeotrope or azeotrope-like compositions of 2-chloro-3, 3, 3-trifluoropropene and water

Abstract

The present application relates to an azeotrope or azeotrope-like composition of 2-chloro-3, 3, 3-trifluoropropene and water. A non-homogeneous azeotrope or azeotrope-like composition comprising 2-chloro-3, 3, 3-trifluoropropene (HFCO-1233xf) and water may comprise from about 0.09% by weight to about 92.69% by weight of 2-chloro-3, 3, 3-trifluoropropene (HFCO-1233xf) and from about 7.31% by weight to about 99.91% by weight of water, and has a boiling point of from about 12.0 DEG C to about 13.6 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 impurities, including water, from 2-chloro-3, 3, 3-trifluoropropene (HFCO-1233xf), and may be used to separate impurities, including water, from 2-chloro-3, 3, 3-trifluoropropene (HFCO-1233xf).

Description

This application is a divisional application of an invention patent application with an application date of November 6, 2020, application number 202011230582.4, and name "Azeotrope or azeotrope-like composition of 2-chloro-3,3,3-trifluoropropene and water". Technical Field

[0001] The present disclosure relates to azeotropes or azeotrope-like compositions, particularly azeotropes or azeotrope-like compositions comprising effective amounts of 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) and water. Background Art

[0002] Hydrofluoroolefins (HFOs), such as tetrafluoropropenes, including 2,3,3,3-tetrafluoropropene (HFO-1234yf), are known to be effective refrigerants, heat transfer media, propellants, foaming agents, blowing agents, gaseous dielectrics, pesticide carriers, polymerization media, particle removal fluids, carrier fluids, polishing abrasives, displacement desiccants, and power cycle working fluids. 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 therefore can meet the increasingly stringent requirements for refrigerants in automotive air conditioners. Therefore, compositions containing HFO-1234yf are among the materials being developed for use in many of the above-mentioned applications.

[0003] A method for producing HFO-1234yf uses 1,1,2,3-tetrachloropropylene (HCFC-1230xa) as a starting material. The method comprises the following three steps: Step (1) 1230xa+3HF→2-chloro-3,3,3-trifluoropropene (1233xf)+3HCl in a gas phase reactor equipped with a solid catalyst; Step (2) 1233xf+HF→2-chloro-1,1,1,2-tetrafluoropropane (244bb) in a liquid phase reactor containing a liquid catalyst; and step (3) 244bb→1234yf+HCl in a gas phase reactor or in a liquid phase.

[0004] In the aforementioned method process, by-products may be generated and / or impurities may be present, including water. It is hoped that all reactants and intermediate products are in as pure a form as possible to limit undesirable side reactions. Therefore, it is necessary to reduce the method for the impurities in the reactants and intermediate products. Summary of the invention

[0005] The present disclosure provides azeotropes or azeotrope-like compositions of 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) and water.

[0006] It is well recognized in the art that it is impossible to predict the formation of azeotropes, and the inventors of the present invention have unexpectedly discovered that 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) and water form azeotrope or azeotrope-like compositions, and particularly form heterogeneous azeotrope or azeotrope-like compositions.

[0007] The present disclosure provides a composition comprising an azeotrope or azeotrope-like composition consisting essentially of effective amounts of 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) and water, preferably wherein the azeotrope or azeotrope-like composition has a boiling point of about 12.0° C. to about 13.6° C., preferably about 13.1° C. to about 13.2° C., at a pressure of about 12.5 psia to about 16.5 psia, preferably about 14.5 psia.

[0008] The azeotrope or azeotrope-like composition can consist essentially of about 0.09 wt % to about 92.69 wt % 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) and about 7.31 wt % to about 99.91 wt % water, preferably wherein the azeotrope or azeotrope-like composition consists essentially of about 65 wt % to about 90 wt % 2-chloro-3,3,3-trifluoropropene (HFCO-1233xf) and about 10 wt % to about 35 wt % water; preferably the azeotrope or azeotrope-like composition consists essentially of about 65.14 wt % to about 86.25 wt % 2-chloro-3,3,3-trifluoropropene (HFCO-1233xf) and about 13.75 wt % to about 34.86 wt % water.

[0009] The present disclosure also provides a method of forming an azeotrope or azeotrope-like composition comprising the step of combining 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) and water to form an azeotrope or azeotrope-like composition consisting essentially of effective amounts of 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) and water and preferably having a boiling point of about 12.0° C. to about 13.6° C. at a pressure of about 12.5 psia to about 16.5 psia.

[0010] The present disclosure further provides a method for separating impurities (including water) from a composition comprising 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) and at least one impurity (which may include water), comprising the steps of: Providing a composition comprising 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) and at least one impurity; varying the relative amounts of 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) and water, and subjecting the composition to conditions effective to form an azeotrope or azeotrope-like composition consisting essentially of or consisting of effective amounts of 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) and water; and separating the azeotrope or azeotrope-like composition from the composition comprising 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf), wherein the separating step may include at least one of phase separation, distillation, drying, and fractionation.

[0011] In the foregoing method, the step of varying the relative amounts of 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) and water may include adding 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) to the composition, adding water to the composition, or adding both 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) and water to the composition.

[0012] The present disclosure also provides a method for preparing 2,3,3,3-tetrafluoropropylene (HFO-1234yf), comprising: converting at least some of the 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) present in the azeotrope or azeotrope-like composition to 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb); and At least some of the 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) is converted to 2,3,3,3-tetrafluoropropene (HFO-1234yf).

[0013] Prior to being converted to 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb), 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) may be separated from water, which is beneficial because it means that 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) may be converted to 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) in the presence of a catalyst that is sensitive to the presence of water. Converting at least some of the 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) to 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) may include reacting 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) with HF, preferably anhydrous HF, in the presence of a catalyst. The catalyst may include a metal halide catalyst, preferably selected from SbCl5, SbF5, TiCl4 or a combination thereof, or a fluorosulfonic acid; and / or converting at least some of the 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) into 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) may be carried out at a temperature of 5-100° C., preferably 50-100° C. Converting at least some of the 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) into 2,3,3,3-tetrafluoropropene (HFO-1234yf) may include reacting 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) with a base, a caustic base, preferably an alkali metal hydroxide, preferably KOH or NaOH. The reaction is preferably 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 reaction 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 conversion of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) to 2,3,3,3-tetrafluoropropylene (HFO-1234yf) may be suitably carried out at superatmospheric pressure, atmospheric pressure or below atmospheric pressure. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a graph of boiling point versus the percentage of 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) in water. DETAILED DESCRIPTION

[0015] 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 of 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 exiting 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), and the like.

[0016] The reaction can be carried out in any reactor suitable for gas phase fluorination reactions. The reactor can be made of a material resistant to the corrosion of hydrogen fluoride and the catalyst, such as Etc. are constructed. 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 the method. Suitable catalysts include, but are not limited to, oxides, hydroxides, halides, oxyhalides, inorganic salts thereof, and mixtures thereof of chromium, aluminum, cobalt, manganese, nickel, and iron, any of which can be optionally 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. Chromium oxide / aluminum oxide catalysts are described in U.S. Patent No. 5,155,082, the contents of which are incorporated herein by reference. Chromium (III) oxides such as crystalline chromium oxide or amorphous chromium oxide are preferred, and amorphous chromium oxide is most preferred. Chromium oxide (Cr2O3) is a commercially available material that can be purchased in a variety of particle sizes. Fluorination catalysts having a purity of at least 98% are preferred. The fluorination catalyst is present in excess, but at least in an amount sufficient to drive the reaction.

[0017] 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 from about 1:1 to about 50:1 in one embodiment; from about 10:1 to about 50:1 in another embodiment; and from 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 a temperature of from about 200°C to about 600°C, from about 200°C to about 400°C in another embodiment, and from about 200°C to about 300°C in another embodiment. In one embodiment, the reaction pressure is from about 0 psig to about 500 psig; from about 20 psig to about 200 psig in another embodiment, and from about 50 psig to about 100 psig in a further embodiment.

[0018] For example, when the compound of Formula I is 1230xa, in one embodiment, the molar ratio of HF to 1230xa 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 a further embodiment, from about 10:1 to about 20:1. In one embodiment, the reaction between HF and 1230xa is carried out at a temperature of from 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. 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.

[0019] 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 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 yet further embodiments, from about 10:1 to about 20:1. In one embodiment, the reaction between HF and 1230xf is carried out at a temperature of from 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. 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 another embodiment, from about 50 psig to about 100 psig.

[0020] 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 a temperature of from 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 from about 0 psig to about 500 psig in one embodiment; from about 20 psig to about 200 psig in another embodiment; and from about 50 psig to about 100 psig in a further embodiment.

[0021] The first step of the reaction need not be limited to gas phase reaction as described above, but can also use liquid phase reaction or liquid phase and gas phase combination to carry out, such as those disclosed in U.S. Patent Application No. 20070197842, the content of which is incorporated herein by reference. It is also contemplated that the reaction can be carried out in batches, continuously or with these combinations. For the embodiment in which the reaction includes 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 these in two or more combinations. In certain embodiments, metal chlorides and metal fluorides are used, including but not limited to SbCl5, SbCl3, SbF5, SnCl4, TiCl4, FeCl3 and these in two or more combinations.

[0022] The fluorination reaction can be carried out to obtain a single pass or multi-pass conversion of at least 1% or more, 5% or more, 10% or more, or about 20% or more. In certain preferred embodiments of the present invention, the starting reactants are converted into 1233xf in a single pass, wherein the reaction conditions achieve a conversion of greater than 75%, greater than 85% in one embodiment, greater than 95% in another embodiment, and greater than 99% in another embodiment. In view of this, the resulting effluent contains a small amount or trace amount of unreacted starting materials, or may be substantially free of these compounds.

[0023] The effluent from the fluorination reaction step (step 1), including any intermediate effluent that may be present in the multistage reactor configuration, is processed to achieve the desired separation degree. For example, in embodiments where the reactor effluent comprises 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf), the effluent will generally also comprise HCl, unreacted HF, and trace amounts, if any, of unreacted starting components (e.g., 1230xa, 1230xf, and / or 240db). The effluent may also comprise one or more byproduct organics, such as under-fluorinated and / or over-fluorinated intermediates. Non-limiting examples of under-fluorinated intermediates include trichlorofluoropropene (1231) isomers and 2,3-dichloro-3,3-difluoropropene (1232xf), and non-limiting examples of over-fluorinated 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 a further embodiment, the impurity is hydrogen fluoride. Other byproduct organics may also include, but are not limited to, dichlorotrifluoropropane (243) isomers and trichlorodifluoropropane (242) isomers, and 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.

[0024] After removal of HCl by distillation and removal of a portion of HF by phase separation, water is added to the remaining effluent from step 1 in an effective amount to form an azeotrope or azeotrope-like mixture comprising 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) and water, which can then be separated from the effluent with its impurities by the techniques described herein. 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) is then separated from water as described herein, and 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) is then fed to the hydrofluorination reactor of step 2 discussed below.

[0025] In step 2 of the above 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 performed in the liquid phase in a liquid phase reactor, which can be TFE or PFA lined. Such a process can be performed in a temperature range of about 70°C to about 120°C and at a pressure of about 50 psig to about 120 psig.

[0026] Any liquid phase fluorination catalyst can be used in the present invention. Non-exhaustive list includes Lewis acid, transition metal halide, transition metal oxide, IVb group metal halide, Vb group metal halide or their combination. Non-exclusive examples of liquid phase fluorination catalyst are antimony halides, tin halides, tantalum halides, titanium halides, niobium halides and molybdenum halides, iron halides, fluorinated chromium halides, fluorinated chromium oxide or their combination. The specific non-exclusive example of liquid phase fluorination catalyst is SbCl , SbCl , SbF , SnCl , TaCl , TiCl , NbCl , MoCl , FeCl , SbCl , SbCl , SbCl , SnCl , TaCl , TiCl , NbCl , MoCl , FeCl , SbCl , SbCl , SbCl , SnCl , TaCl , TiCl , NbCl , MoCl , FeCl , or their combination. Antimony pentachloride is most preferred.

[0027] If the catalyst becomes deactivated, the catalyst can be readily regenerated by any means known in the art. One suitable method of regenerating the catalyst includes flowing a chlorine gas stream over the catalyst. For example, about 0.002 pounds to about 0.2 pounds of chlorine gas per hour may be added to the liquid phase reaction for each pound of 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 hour to about 2 hours or continuously.

[0028] The reaction step 2 in which the 244bb product is formed need not be limited to a liquid phase reaction, but may also be carried out using a gas phase reaction or a combination of liquid and gas phases, such as those disclosed in U.S. Published Patent Application No. 20070197842, the contents of which are incorporated herein by reference. To this end, 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 for such reactions, and the fluorinating agent may include those generally known in the art, such as, but not limited to, hydrogen fluoride.

[0029] The effluent from the hydrofluorination reaction step (step 2) is treated to achieve the desired degree of 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-trifluoropropene (HCFO-1233xf), perfluorinated byproducts 245cb, HCl and Cl2). For example, the product stream is fed to a light material 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 light material removal tower bottom stream 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.

[0030] 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.

[0031] 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 +Component halogens 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 process may include any of those known in the art, particularly those using HF, F2, HCl, Cl2, HBr, Br2, HI, and I2 as halogenation sources.

[0032] 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 metals as alloys or mixtures. The catalyst may be supported or unsupported. Useful examples of metal alloys include, but are not limited to, SS 316, 400, 825, 600 and 625. These catalysts may be provided as discrete supported or unsupported elements and / or as part of the reactor and / or reactor wall.

[0033] Exemplary but non-limiting catalysts include activated carbon, stainless steel (e.g., SS 316), austenitic nickel-based alloys (e.g., 625), nickel, fluorinated 10% CsCl / MgO, and 10% CsCl / MgF2, etc. In one embodiment, the reaction temperature is from about 300°C to about 550°C, and the reaction pressure can be from about 0 psig to about 150 psig. The reactor effluent can be fed to a caustic scrubber or a distillation column to remove the HCl byproduct 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.

[0034] Step 3 can also be carried out in the liquid phase. 2- chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) is converted into 2,3,3,3-tetrafluoropropylene (HFO-1234yf) can be carried out, for example, by using a base to dehydrochlorinate 2- chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb). 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 their combinations. Preferred examples of caustic bases are KOH, NaOH, LiOH, Mg (OH) 2, Ca (OH) 2, CaO and their combinations. Caustic bases can be added to the reaction in solid form or solution. When provided in a solution, preferably the solvent is water or alcohol, preferably MeOH or EtOH. KOH is particularly preferred, and is preferably provided as an aqueous solution, preferably comprising about 5 wt % to about 62 wt % KOH, preferably 5 wt % to 55 wt % KOH. Liquid phase dehydrochlorination is preferably carried out in an aqueous environment. In the case of liquid phase step 3, the aqueous environment is an environment in which the liquid phase reaction mixture contains 5% to 80% by weight of water, preferably 10% to 60% by weight of water, more preferably 20% to 40% by weight of water. It is also preferred to use a phase transfer catalyst, particularly when the reaction is carried out in an aqueous environment, because it is believed to contribute to reactivity by promoting close contact between the base and 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb). 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 with halogen anions), cryptands (e.g., N[CH2CH2OCH2CH2OCH2CH2]3N), polyalkylene glycols (e.g., poly(ethylene glycol)), derivatives thereof, and combinations thereof. In one embodiment, the phase transfer catalyst is Aliquat 336. Preferred onium salts, 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.

[0035] The liquid phase variant 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) can suitably occur at superatmospheric pressure, atmospheric pressure or below atmospheric pressure. These temperatures and pressures are particularly useful when step 3 is carried out in the liquid phase using a base as described above.

[0036] 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 contents of which are incorporated herein.

[0037] 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 (wherein steps (2) and (3) are the same as those described above): Step (1): in the gas phase (with or without a catalyst) 243db→1233xf+HCl or in the liquid phase (optionally with a phase transfer catalyst, and / or a solvent and / or a salt) 243db+base→1233xf+H2O; Step (2): 1233xf + HF → 244bb in a liquid phase reactor containing a liquid hydrofluorination catalyst; and Step (3): 244bb→1234yf+HCl in a gas phase reactor (with or without catalyst) or in liquid phase.

[0038] In the optional method, wherein 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 a gas phase using a catalyst or can occur in a 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 a 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.Other methods may be used when starting with a compound of formula (III), as will be known to those skilled in the art.

[0039] For embodiments where it is desirable to maintain moisture and impurity-free conditions during 1234yf synthesis, the reactants and intermediates may be purified. For example, it is desirable to remove impurities, including water, from 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf).

[0040] It has been found that 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) and water form heterogeneous azeotropes and azeotrope-like compositions or mixtures, and the present disclosure provides heterogeneous azeotropes or azeotrope-like compositions comprising 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) and water. The azeotrope or azeotrope-like composition may consist essentially of 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) and water, or the azeotrope or azeotrope-like composition may consist of 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) and water.

[0041] The present inventors have experimentally discovered that 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) and water form an azeotrope or azeotrope-like composition.

[0042] 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 is formed, then at constant pressure, the boiling point of the heterogeneous azeotrope will be lower than the lower boiling component ("minimum boiling azeotrope").

[0043] An "azeotrope" (or "azeotrope") composition is a unique combination of two or more components. Azeotropes can be homogeneous (having one liquid phase) or heterogeneous (having two liquid phases). Azeotrope compositions can be characterized in various ways. For example, at a given pressure, an azeotrope composition boils at a constant characteristic temperature, which 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 when boiling. Azeotrope compositions do not fractionate when boiling or evaporating. Therefore, the components of an azeotrope composition cannot be separated during a phase change.

[0044] A uniform azeotrope composition is also characterized in that at a characteristic azeotropic temperature, the bubble point pressure of the liquid phase is the same as the dew point pressure of the vapor phase. The behavior of an azeotrope composition is opposite to that of a non-azeotrope composition, wherein the liquid composition of the non-azeotrope composition changes to a significant degree during boiling or evaporation.

[0045] However, it will be appreciated by those of ordinary skill in the art that the composition and boiling point of an azeotrope composition will vary to some extent under different pressures. Thus, depending on the temperature and / or pressure, an azeotrope composition may have a variable composition. Thus, it will be appreciated by those of ordinary skill in the art that a composition range rather than a fixed composition may be used to define an azeotrope composition. In addition, an azeotrope may be defined by the precise weight percentages of each component of the composition characterized by a fixed boiling point at a specified pressure.

[0046] An "azeotrope-like" composition is a composition of two or more components that behaves essentially the same as an azeotrope composition. Thus, for purposes of this disclosure, an azeotrope-like composition is a combination of two or more different components that, when in liquid form at a given pressure in the case of a uniform azeotrope, will boil at a substantially constant temperature, and which will provide a vapor composition that is substantially the same as the liquid composition undergoing boiling. In the case of a non-uniform azeotrope, two liquid phases are formed at a given pressure that will be covered by a vapor composition. Each of the two liquid phases and the vapor phase will remain substantially constant when boiling.

[0047] For purposes of this disclosure, an azeotrope-like composition is a composition or range of compositions that boils at a pressure of about 12.5 psia to about 16.5 psia, preferably in the temperature range of about 12.0°C to about 13.6°C.

[0048] Azeotropes or azeotrope-like compositions can be identified using a number of different methods.

[0049] For purposes of this disclosure, the azeotrope or azeotrope-like compositions are 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 vapor-liquid equilibrium temperature.

[0050] The boiling points of each component are measured individually at constant pressure. As will be appreciated by those skilled in the art, for binary azeotropes or azeotrope-like compositions, the boiling point of one component of the composition is initially measured. The second component of the composition is then added in varying amounts, and the boiling point of each resulting composition is measured at the constant pressure using an ebulliometer. In the case of a ternary azeotrope, the initial composition will comprise a binary blend, and the third component is added in varying amounts. The boiling point of each resulting ternary composition is measured at the constant pressure using an ebulliometer.

[0051] The measured boiling points are plotted against the composition of the composition tested, e.g., for a binary azeotrope, against the amount of the second component added to the composition (expressed as weight % or mole %). The presence of an azeotrope composition can be identified by observing a maximum or minimum boiling temperature that is higher or lower than the boiling point of any individual component.

[0052] As will be appreciated by those skilled in the art, identification of an azeotrope or azeotrope-like composition is made by comparing the change in boiling point of the composition relative to the boiling point of the first component when a 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.

[0053] As previously mentioned, at the highest or lowest boiling point, the composition of the vapor phase will be the same as the composition of the liquid phase. Thus, the azeotrope-like composition is a composition of components that provide a substantially constant lowest or highest boiling point (i.e., a boiling point of about 12.0°C to about 13.6°C, preferably about 13.1°C to about 13.2°C) at a pressure of about 12.5 psia to about 16.5 psia, preferably about 14.5 psia, at which substantially constant boiling point the composition of the vapor phase will be substantially the same as the composition of the liquid phase.

[0054] The present disclosure provides an azeotrope or azeotrope-like composition comprising effective amounts of 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) and water to form an azeotrope or azeotrope-like composition. As used herein, the term "effective amount" is the amount of each component that, when combined with another component, results in the formation of an azeotrope or azeotrope-like composition.

[0055] The azeotrope or azeotrope-like composition of the present invention can consist essentially of or consist of the combination of 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) and water.

[0056] As used herein, with respect to the components of an azeotrope or azeotrope-like composition or mixture, the term "consisting essentially of" means that the composition comprises the specified components in azeotropic or azeotrope-like ratios, and may include additional components, provided that the additional components do not form a new azeotrope or azeotrope-like system. For example, azeotropic mixtures consisting essentially of two compounds are those that form a binary azeotrope, which optionally may include 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).

[0057] The present disclosure also provides a method for forming an azeotrope or azeotrope-like composition by mixing, combining or blending an effective amount of 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) and water. Any of the rich and diverse 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, as part of an intermittent or continuous reaction and / or method, or by a combination of two or more such steps, 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) and water can be mixed, blended or combined by hand and / or machine. The components can be provided in the desired amount, for example, by weighing and then combining the amounts.

[0058] The azeotrope or azeotrope-like composition having a boiling point of about 12.0°C to about 13.6°C at a pressure of about 12.5 psia to about 16.5 psia can also consist essentially of or consist of about 0.09 wt % to about 92.69 wt % 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) and about 7.31 wt % to about 99.91 wt % water.

[0059] The present disclosure also provides compositions comprising the azeotrope or azeotrope-like compositions. For example, compositions comprising at least about 14% by weight of the azeotrope or azeotrope-like compositions, or at least about 21% by weight of the azeotrope or azeotrope-like compositions, or at least about 25% by weight of the azeotrope or azeotrope-like compositions, or at least about 70% by weight of the azeotrope or azeotrope-like compositions, or at least about 90% by weight of the azeotrope or azeotrope-like compositions, or at least 95% by weight of the azeotrope or azeotrope-like compositions, or at least about 99% by weight of the azeotrope or azeotrope-like compositions are provided.

[0060] The azeotrope or azeotrope-like compositions disclosed herein comprising, consisting essentially of, or consisting of effective amounts of 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) and water can be used to separate impurities from 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf).

[0061] Preparation of azeotropic or azeotrope-like compositions comprising, consisting essentially of, or consisting of effective amounts of 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) and water such that separation techniques such as azeotropic distillation can be used to remove impurities, including water, from 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf).

[0062] Specifically, an azeotrope or azeotrope-like composition comprising, consisting essentially of, or consisting of an effective amount of 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) and water can be formed from a composition comprising 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf), water, and at least one impurity (which may include water). After the azeotrope or azeotrope-like composition is formed, the azeotrope or azeotrope-like composition can be separated from other compounds by a suitable method, such as by distillation, phase separation, drying, or fractionation. Drying can be achieved by adding a desiccant such as a molecular sieve.

[0063] In one example, the present disclosure provides a method for separating impurities from 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf), the method comprising the steps of providing a primary composition of crude 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf), varying the relative amounts of 2-chloro-3,3,3-trifluoropropene and water, and subjecting the primary composition to conditions effective to form a secondary composition, the secondary composition being an azeotrope or azeotrope-like composition consisting essentially of or consisting of an effective amount of 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) and water, and separating the secondary composition from the primary composition by separation techniques such as phase separation, distillation or fractionation. Thereafter, the secondary composition may be subjected to further separation, purification or drying steps to obtain purified 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf). The step of varying the relative amounts of HCFO-1233xf and water may include adding HCFO-1233xf to the composition, adding water to the composition, or adding both HCFO-1233xf and water to the composition.

[0064] The azeotrope or azeotrope-like composition comprising, consisting essentially of, or consisting of effective amounts of 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) and water can be used to produce 2,3,3,3-tetrafluoropropene (HFO-1234yf). For example, as described above, the azeotrope or azeotrope-like composition can be used to purify 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) prior to step 3 of the process. The 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) removed from 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) by forming the azeotrope can then be converted into further 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) before being converted into 2,3,3,3-tetrafluoropropene (HFO-1234yf). Similarly, if 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) is present in the crude product, for example, by dehydrofluorination of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) in step 3, the azeotrope or azeotrope-like composition may be formed after step 3. Although not inevitable, the azeotrope or azeotrope-like composition may also be formed in the reaction of preparing 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) from 1,2-dichloro-3,3,3-trifluoropropane (HCFC-243db). The presence of the azeotrope or azeotrope-like composition will depend on factors such as whether the azeotropy is destroyed by other substances present. Although not inevitable, examples of how the azeotrope or azeotrope-like composition may be formed include the following: - When water is present as solvent in the reaction, for example when the reaction is carried out in an aqueous environment, for example when the base is used as an aqueous solution.

[0065] When water is released during the reaction. For example, dehydrochlorination of HCFC-243db with hydroxide ions, in the presence or absence of water as solvent, will release water molecules according to the following equation: CF3CHClCCH2Cl+ - OH→CF3CCl=CH2+Cl - +H2O. Those skilled in the art will appreciate that when other types of bases are used, especially caustic bases, it is possible for water molecules to be precipitated.

[0066] The following non-limiting examples serve to illustrate the invention.

[0067] Example Example 1 - Vapor Liquid Equilibrium (VLE) Study The ebulliometer consisting of a vacuum jacketed tube with a dry ice-cooled condenser on top was equipped with a quartz thermometer. The ebulliometer was initially loaded with 14.11 grams of 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf). Water was then added incrementally, and the temperature of the mixture was recorded at each water increment. The mixture temperature reached a minimum and then remained substantially constant as additional water was added, indicating the formation of a heterogeneous azeotrope. The ambient pressure during the measurement was 14.5 psia. The mixture composition and the measured temperatures are shown in Table 1. The data for Table 1 are shown in FIG. Figure 1 middle.

[0068] Table 1 Weight% HCFO-1233xf Weight% Water Temperature(℃) 100 0.00 13.44 99.65 0.35 13.26 98.95 1.05 13.23 97.58 2.42 13.20 95.6 4.40 13.18 93.07 6.93 13.17 90.68 9.32 13.17 86.25 13.75 13.15 82.23 17.77 13.14 78.56 21.44 13.14 75.21 24.79 13.14 71.77 28.23 13.14 68.30 31.70 13.14 65.14 34.86 13.14 .

[0069] Example 2 - Vapor-Liquid-Liquid Equilibrium (VLLE) Measurements A 50:50 weight mixture of 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) and water was prepared in a Teflon cell at 23°C. Two separate phases were observed in the cell, indicating that a heterogeneous azeotrope had been formed. The upper (water-rich) and lower (2-chloro-3,3,3-trifluoropropene (HCFO-1233xf)-rich) phases were separated and analyzed. The compositions of the two phases are shown in Table 2 below.

[0070] Table 2 Components Upper phase weight % Lower phase weight % HCFO-1233xf 0.09 92.69 water 99.91 7.31 .

[0071] Example 3-Purification of 2-chloro-3,3,3-trifluoropropene (HFCO-1233xf) In this embodiment, a composition is provided, which comprises 2-chloro-3,3,3-trifluoropropene (HFCO-1233xf) and impurities (which may be water). An effective amount of water is added to the composition, and the composition is subjected to conditions that effectively form an azeotrope or azeotrope-like composition, which is substantially composed of or is composed of an effective amount of 2-chloro-3,3,3-trifluoropropene (HFCO-1233xf) and water. Then, the azeotrope or azeotrope-like composition is separated from the composition comprising the main compound by separation techniques such as phase separation, distillation and / or fractionation. Once 2-chloro-3,3,3-trifluoropropene (HFCO-1233xf) has been separated, it can be further dried by adding a desiccant.

[0072] Example 4 - Separation of Water as an Impurity In this embodiment, a composition is provided, which comprises a major compound, such as 2-chloro-3,3,3-trifluoropropene (1233xf), and water as an impurity. An effective amount of water is added to the composition, and the composition is subjected to conditions that effectively form an azeotrope or azeotrope-like composition consisting of an effective amount of 2-chloro-3,3,3-trifluoropropene (1233xf) and water. Then, the azeotrope or azeotrope-like composition is separated from the composition comprising the major compound by separation techniques such as phase separation, distillation and / or fractionation. Once 2-chloro-3,3,3-trifluoropropene (HFCO-1233xf) has been separated, it can be further dried by adding a desiccant.

[0073] Example 5 - Separation of Water as an Impurity In this embodiment, a composition is provided, which comprises a major compound, such as 2-chloro-3,3,3-trifluoropropene (1233xf), and water as an impurity. An effective amount of 2-chloro-3,3,3-trifluoropropene (1233xf) is added to the composition, and the composition is subjected to the conditions of effectively forming an azeotrope or azeotrope-like composition consisting of an effective amount of 2-chloro-3,3,3-trifluoropropene (1233xf) and water. Then, the azeotrope or azeotrope-like composition is separated from the composition comprising the major compound by separation techniques such as phase separation, distillation and / or fractionation. Once 2-chloro-3,3,3-trifluoropropene (HFCO-1233xf) has been separated, it can be further dried by adding a desiccant.

[0074] Example 6 - Conversion of 1,2-dichloro-3,3,3-trifluoropropane (HCFC-243db) to 2-chloro-3,3,3-trifluoropropane Representative process of olefins (1233xf) 86 grams of 12 wt% NaOH solution and 36.5 grams of 243db were loaded into a shaking tube reactor. The reactor was cooled to -10°C and evacuated briefly. It was then heated to 55°C without stirring. Once the temperature reached 47°C, it was shaken and heated to 55°C. It was then kept at ~55°C for 60 minutes. The estimated mixing power was 30-40HP / 1000 gallons. During the reaction, the pressure increased continuously from -6.34psig to -47psig. Based on the temperature and pressure curve, it was estimated that the reaction would take about 25 minutes to reach 98% conversion. The product was analyzed by GC-MS, and the analysis showed that about 98% of the 243db was converted: Compound GC area % HCFO-1233xf 96.97％ HCFO-1233zd 0.11％ HCFC-243fa 0.43％ HCFC-243db 1.06％ HCFC-233ab 1.00％ other 0.43％ .

[0075] Example 7 - Conversion of 2-chloro-3,3,3-trifluoropropene (1233xf) to 2-chloro-1,1,1,2-tetrafluoropropane Representative process of (HCFC-244bb)About 327 grams of HF, about 50 grams of 1233xf and about 75 grams of SbCl5 are loaded into a 1-L autoclave. Under a pressure of about 620psig, the reaction mixture was stirred at a temperature of about 80 ℃ for about 3 hours. After the reaction, the reactor was cooled to about 0 ℃, and then about 300 milliliters of water were slowly added to the autoclave through about 45 minutes. After stirring, water was added completely, the reactor was cooled to room temperature, and then the top gas was transferred to another collecting cylinder. CF3CFClCH3 productivity is about 90% under about 98% 1233xf conversion level. Other major byproducts are CF3CF2CH3 (2%), and the unidentified isomer (8%) of the C4 compound of the general formula C4H3Cl3F4.

[0076] Example 8 - Conversion of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) to 2,3,3,3-tetrafluoropropene Representative process of (HFO-1234yf) 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 TM Add to the reactor.Then close the reactor and test the pressure.Then 294 grams of organic mixture and 270 grams of 45% KOH are added to the reactor.Analysis of the organic mixture using gas chromatography (GC) shows 8.1GC area % of 1234yf, 89.5GC area % of 244bb, and 1.8GC area % of 1233xf.Then open the agitator and heat the reactor to 55 ° C.When (after about 2 hours) reaching 55 ° C, the pressure in the reactor is increased to 55 psig from the initial 10psig.The reactor is kept at 55 ° C for 4 hours, and the pressure is further increased to 78psig.After the reaction is completed, the GC analysis of the organic contents of the reactor shows 64.2GC area % of 1234yf, 33.2GC area % of 244bb, 2.2GC area % of 1233xf, and 0.4GC area % of unknowns.

[0077] The above synthesis examples are included to illustrate the reactions and are not comments on whether the claimed azeotrope or azeotrope-like composition is present in the synthesis.

[0078] Example 9 - Representative Purification of HCFO-1233xf The composition comprising HCFO-1233xf and water is purified to provide a purified HCFO-1233xf stream.

[0079] 1000 kg of the mixture (comprising 926.9 kg of HCFO-1233xf and 73.1 kg of water) is charged to the reboiler of a batch distillation system consisting of a reboiler, a multi-stage rectification section and a condenser, the multi-stage rectification section being filled with a random packing such as available from Koch-Glitsch The condenser is cooled with flowing cooling water at about 5°C at the inlet of the condenser. The reboiler has a half-pipe jacket for steam. The reboiler charge may be an organic phase of a mixture of HCFO-1233xf and water subjected to phase separation, wherein the aqueous phase precipitates to the upper part.

[0080] The batch distillation system is used to distill an overhead stream containing essentially an azeotrope of HCFO-1233xf and water, leaving essentially HCFO-1233xf containing about 0.039 wt% water in the reboiler. See summary in Table 3. The material in the reboiler can be further dried by passing it through a desiccant such as 3A molecular sieves.

[0081] Table 3 - Composition Reboiler charge (kg) Distillate (kg) Bottom material (kg) HCFO-1233xf 926.9 158.0* 768.9 water 73.1 72.8 0.3 .

[0082] Under these conditions, the azeotropic composition was 68 wt% HCFO-1233xf. A slight excess of the azeotrope was recovered overhead.

[0083] Although this example shows purification in a batch distillation scheme, one skilled in the art could adapt it for continuous distillation purification.

[0084] All aspects Aspect 1 is a composition comprising an azeotrope or azeotrope-like composition consisting essentially of effective amounts of 2-chloro-3,3,3-trifluoropropene (HFCO-1233xf) and water.

[0085] Aspect 2 is the composition of aspect 1, wherein the azeotrope or azeotrope-like composition has a boiling point of about 12.0°C to about 13.6°C at a pressure of about 12.5 psia to about 16.5 psia.

[0086] Aspect 3 is the composition of aspect 1 or aspect 2, wherein the azeotrope or azeotrope-like composition consists essentially of about 0.09 wt % to about 92.69 wt % 2-chloro-3,3,3-trifluoropropene (HFCO-1233xf) and about 7.31 wt % to about 99.91 wt % water.

[0087] Aspect 4 is a method of forming an azeotrope or azeotrope-like composition comprising the step of combining 2-chloro-3,3,3-trifluoropropene (HFCO-1233xf) and water to form an azeotrope or azeotrope-like composition consisting essentially of effective amounts of 2-chloro-3,3,3-trifluoropropene (HFCO-1233xf) and water and having a boiling point of about 12.0° C. to about 13.6° C. at a pressure of about 12.5 psia to about 16.5 psia.

[0088] Aspect 5 is the method of aspect 4, wherein the combining step comprises combining about 0.09 wt % to about 92.69 wt % of 2-chloro-3,3,3-trifluoropropene (HFCO-1233xf) and about 7.31 wt % to about 99.91 wt % of water.

[0089] Aspect 6 is a method for separating impurities including water from 2-chloro-3,3,3-trifluoropropene (HFCO-1233xf) from a composition comprising 2-chloro-3,3,3-trifluoropropene (HFCO-1233xf) and at least one impurity, comprising the steps of providing a composition comprising 2-chloro-3,3,3-trifluoropropene (HFCO-1233xf) and at least one impurity, changing the relative amounts of 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) and water and subjecting the composition to conditions effective to form an azeotrope or azeotrope-like composition consisting essentially of or consisting of effective amounts of 2-chloro-3,3,3-trifluoropropene (HFCO-1233xf) and water, and separating the azeotrope or azeotrope-like composition from 2-chloro-3,3,3-trifluoropropene (HFCO-1233xf).

[0090] Aspect 7 is the method of aspect 6, wherein the separation step comprises at least one of phase separation, distillation, and fractionation.

[0091] Aspect 8 is a method according to aspect 6 or aspect 7, further comprising separating 2-chloro-3,3,3-trifluoropropene from water.

[0092] Aspect 9 is the method of any one of aspects 6-8, wherein 2-chloro-3,3,3-trifluoropropene is separated from water using liquid-liquid phase separation.

[0093] Aspect 10 is the method of any one of aspects 6-9, wherein 2-chloro-3,3,3-trifluoropropene is separated from water using distillation.

[0094] Aspect 11 is the method of any one of aspects 6-10, wherein 2-chloro-3,3,3-trifluoropropene is separated from water using at least one drying agent.

[0095] Aspect 12 is the method of any one of aspects 6 to 11, wherein the water is removed first by liquid-liquid phase separation and then by a second method selected from distillation, one or more drying agents, and combinations thereof.

[0096] Aspect 13 is the method of any one of aspects 6-12, wherein the step of varying the relative amounts of 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) and water comprises adding 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) to the composition.

[0097] Aspect 14 is the method of any of aspects 6-13, wherein the step of varying the relative amounts of 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) and water comprises adding water to the composition.

[0098] Aspect 15 is the method of any of aspects 6-14, wherein the step of varying the relative amounts of 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) and water comprises adding both 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) and water to the composition.

[0099] As used herein, the phrase "within any range defined between any two preceding values" literally means that any range can be selected from any two values ​​listed before such phrase, regardless of whether the values ​​are in the lower part of the list or in the upper part of the list. For example, a pair of values ​​can be selected from two lower values, two higher values, or a lower value and an upper value.

[0100] As used herein, the singular forms "a", "an" and "the" include plural forms unless the context clearly dictates otherwise. In addition, when quantities, concentrations or other values ​​or parameters are given as intervals, preferred ranges or lists of preferred upper and lower values, this should be understood as specifically disclosing all intervals formed by any pair of any interval upper limit or preferred value and any interval lower limit or preferred value, regardless of whether the interval is disclosed separately. When a numerical interval is cited herein, unless otherwise stated, the interval is intended to include its endpoints and all integers and fractions within the interval. When an interval is defined, the disclosed range is not intended to be limited to the specific values ​​listed.

[0101] As used herein, the phrase "within any range defined between any two preceding values" literally means that any range can be selected from any two values ​​listed before such phrase, regardless of whether the values ​​are in the lower part of the list or in the upper part of the list. For example, a pair of values ​​can be selected from two lower values, two higher values, or a lower value and an upper value.

[0102] It should be understood that the foregoing description is only an illustration of the present disclosure. Those skilled in the art may come up with various substitutions and modifications without departing from the present disclosure. Therefore, the present disclosure is intended to cover all such substitutions, modifications and variations that fall within the scope of the appended claims.

Claims

1. A composition comprising an azeotrope or azeotrope-like composition consisting essentially of effective amounts of 2-chloro-3,3,3-trifluoropropene (HFCO-1233xf) and water.

2. The composition of claim 1, wherein the azeotrope or azeotrope-like composition has a boiling point of about 12.0°C to about 13.6°C, preferably about 13.1°C to about 13.2°C, at a pressure of about 12.5 psia to about 16.5 psia, preferably about 14.5 psia.

3. The composition of claim 1 or claim 2, wherein the azeotrope or azeotrope-like composition consists essentially of about 0.09 wt % to about 92.69 wt % 2-chloro-3,3,3-trifluoropropene (HFCO-1233xf) and about 7.31 wt % to about 99.91 wt % water; Preferably, wherein the azeotrope or azeotrope-like composition consists essentially of about 65 wt % to about 90 wt % 2-chloro-3,3,3-trifluoropropene (HFCO-1233xf) and about 10 wt % to about 35 wt % water; Preferably, the azeotrope or azeotrope-like composition consists essentially of about 65.14 wt% to about 86.25 wt% 2-chloro-3,3,3-trifluoropropene (HFCO-1233xf) and about 13.75 wt% to about 34.86 wt% water.

4. A method of forming an azeotrope or azeotrope-like composition comprising the step of combining 2-chloro-3,3,3-trifluoropropene (HFCO-1233xf) with water to form an azeotrope or azeotrope-like composition as defined in any one of claims 1 to 3.

5. A method for separating impurities including water from 2-chloro-3,3,3-trifluoropropene (HFCO-1233xf) from a composition comprising 2-chloro-3,3,3-trifluoropropene (HFCO-1233xf) and at least one impurity, the method comprising the steps of: Providing a composition comprising 2-chloro-3,3,3-trifluoropropene (HFCO-1233xf) and at least one impurity; varying the relative amounts of 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) and water and subjecting the composition to conditions effective to form an azeotrope or azeotrope-like composition as defined in any one of claims 1 to 3; and The azeotrope or azeotrope-like composition is separated from 2-chloro-3,3,3-trifluoropropene (HFCO-1233xf).

6. The method of claim 5, wherein the separation step comprises at least one of phase separation, distillation and fractionation; and / or Also included is separating 2-chloro-3,3,3-trifluoropropene from water using liquid-liquid phase separation, distillation, or at least one drying agent.

7. The method of claim 5, wherein water is removed first by liquid-liquid phase separation and then by a second method selected from the group consisting of distillation, one or more desiccants, and combinations thereof.

8. The method of claim 6, wherein the step of varying the relative amounts of 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) and water comprises: adding 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) to the composition; adding water to the composition; or Both 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) and water were added to the composition.

9. A method for preparing 2,3,3,3-tetrafluoropropylene (HFO-1234yf), comprising: converting at least some of the 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) present in the azeotrope or azeotrope-like composition defined in any one of claims 1 to 3 into 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb); and At least some of the 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) is converted to 2,3,3,3-tetrafluoropropene (HFO-1234yf).

10. A process according to claim 9, wherein 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) is separated from water before being converted into 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb), preferably by a process as defined in claim 6 or claim 7.

11. The process of claim 9 or claim 10, wherein converting at least some of the 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) to 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) comprises reacting 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) with HF, preferably anhydrous HF, in the presence of a catalyst.

12. The method according to claim 11, wherein: The catalyst comprises a metal halide catalyst, preferably selected from SbCl5, SbF5, TiCl4 or a combination thereof, or fluorosulfonic acid; and / or The conversion of at least some of the 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) into 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) is carried out at a temperature of 5-100°C, preferably 50-100°C.

13. The method of any one of claims 9-12, wherein converting at least some of the 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) to 2,3,3,3-tetrafluoropropene (HFO-1234yf) comprises reacting the 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) with a base; Preferably 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; and / or Preferably the base is a caustic, preferably an alkali metal hydroxide, preferably KOH or NaOH; and / or It 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.

14. HFO-1234yf is used as a refrigerant in automotive air conditioners.

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

16. A method for preparing HFO-1234yf, the method comprising the following three steps: Step (1): in the gas phase (with or without a catalyst) 243db→1233xf+HCl or in the liquid phase (optionally with a phase transfer catalyst, and / or a solvent and / or a salt) 243db+base→1233xf+H2O; Step (2): 1233xf + HF → 244bb in a liquid phase reactor containing a liquid hydrofluorination catalyst; and Step (3): 244bb→1234yf+HCl in a gas phase reactor (with or without catalyst) or in liquid phase.

17. A method for converting at least some 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) to 2,3,3,3-tetrafluoropropene (HFO-1234yf), comprising: 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°C to about 80°C.

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