Process for the separation of mixtures containing 1,1,1,3-tetrafluoropropane, 3,3,3-trifluoropropene, and hydrogen fluoride and their azeotropic mixtures

Abstract

Disclosed herein is a process for separating hydrogen fluoride (HF) from a composition comprising 1,1,1,3-tetrafluoropropane (HFC-254fb), 3,3,3-trifluoropropene (HFO-1243zf), and a molar excess of HF, comprising azeotropic distillation. Also disclosed herein is a process for separating HFC-254fb from an HFC-254fb-rich stream comprising HFC-254fb, HFO-1243zf, and HF, comprising azeotropic distillation. Also disclosed herein is a process for separating HFC-254fb from a process stream comprising HFC-254fb, HFO-1243zf, and a molar excess of HF, comprising azeotropic distillation. Also disclosed herein are azeotropic or near-azeotropic compositions comprising mixtures of HFC-254fb / HF, HFO-1243zf / HF, HFC-254fb / HF, HFO-1243zf / HF, and HF.

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims priority to U.S. Provisional Patent Application No. 63 / 426,596, filed November 18, 2022, the disclosure of which is incorporated herein by reference in its entirety.

[0002] FIELD OF THE INVENTION The present disclosure relates to a process for separating a mixture of hydrogen fluoride (HF) and a fluoroolefin. More specifically, the present disclosure relates to a process for separating a mixture containing 1,1,1,3-tetrafluoropropane (HFC-254fb; CFCHCHF), 3,3,3-trifluoropropene (HFO-1243zf; CFCH=CH), and HF. The present disclosure also relates to an azeotropic or near-azeotropic mixture for the separation. [Background technology]

[0003] The refrigeration industry continues to address environmental impacts by using refrigerants with minimal or no ozone depleting potential (ODP), and more recently, developing materials and processes with low global warming potential (GWP). To mitigate these environmental concerns, there continues to be a need for heat transfer compositions that have low global warming potential ("GWP") and maintain or improve performance. While certain hydrofluoroolefins (HFOs) have low GWP, there remains a need for manufacturing processes that provide fluoroolefins with lower global warming potential.

[0004] The production of fluoroolefins is typically a multi-step process that can produce intermediate mixtures of hydrofluorocarbons (HFCs), hydrochlorofluorocarbons (HCFCs), hydrochlorofluoroolefins (HCFOs), and / or hydrofluoroolefins (HFOs), and hydrogen fluoride (HF). Separation of such mixtures is not always easily accomplished. Existing methods of distillation and decantation are often ineffective at separating these compounds. Aqueous scrubbing can be effective, but requires the use of large amounts of scrubbing solution and produces excessive waste as well as a wet product that must subsequently be dried. Summary of the Invention [Problem to be solved by the invention]

[0005] Therefore, new methods are needed to separate HF from fluoroolefins, hydrofluoroolefins, hydrofluoroolefins, chlorofluoroolefins, hydrochlorofluoroolefins, hydrochlorofluorocarbons, and / or hydrofluorocarbons. [Means for solving the problem]

[0006] The present invention overcomes problems associated with conventional processes and provides compositions and methods for separating HF from fluoroolefin-containing compositions produced from processes including, but not limited to, the production of 3,3,3-trifluoropropene (HFO-1243zf, CFCH=CH), which can be part of the general process for producing 2,3,3,3-tetrafluoropropene (HFO-1234yf; CFCF=CH). Producing 3,3,3-trifluoropropene can include the fluorination of 1,1,1,3-tetrachloropropane (HCC-250fb; CClCHCHCl) with the formation of the by-product 1,1,1,3-tetrafluoropropane (HFC-254fb).

[0007] In one embodiment of the present invention disclosed herein, the process stream containing 1,1,1,3-tetrafluoropropane (HFC-254fb) and 3,3,3-trifluoropropene (HFO-1243zf) contains sufficient HF to also form azeotropic or near-azeotropic compositions containing 1,1,1,3-tetrafluoropropane (HFC-254fb).

[0008] In one embodiment, the present disclosure provides a process for separating hydrogen fluoride (HF) from a process stream containing 1,1,1,3-tetrafluoropropane (HFC-254fb), 3,3,3-trifluoropropene (HFO-1243zf), and a molar excess of HF, i.e., a sufficient amount of HF to surprisingly form an azeotropic or near-azeotropic composition containing at least 1,1,1,3-tetrafluoropropane (HFC-254fb).

[0009] The process disclosed herein includes distilling a process stream in a first distillation column under boiling conditions for azeotropes formed between HFC-254fb, HFO-1243zf, and excess HF, e.g., mixtures of HFC-254fb and HF, and HFO-1243zf and HF. The process also includes forming a first distillate stream comprising a composition of HFC-254fb, HFO-1243zf, and a sufficient amount of HF to form azeotropic or near-azeotropic compositions between HFC-254fb and HF, and between HFO-1243zf and HF, and a first (bottom) stream of HF essentially free of HFC-254fb and HFO-1243zf from the first distillation column.

[0010] In another embodiment, the present disclosure provides a process for separating 1,1,1,3-tetrafluoropropane (HFC-254fb) from a stream comprising HFC-254fb, 3,3,3-trifluoropropene (HFO-1243zf), and a molar excess of HF by using an HFC-254fb / HF azeotrope or near-azeotrope. The one or more additional compounds may be, but are not limited to, propane, trifluoroethane, 1,1,1,2-tetrafluoroethane (HFC-134a; CF3CH2F), 1,1,3,3,3-pentafluoropropene (HFO-1225ZC), difluoroethane, 1,1,1-trifluoropropane (HFC-143a; CH3CH2CF3), monofluoroethane (HFC-161), 1,1,1,2-tetrafluoropropane (HFC-254eb), 2-chloro-3,3,3-trifluoropropene (HFO-1233xf), 1-chloro-3,3,3-trifluoropropene (HFO-1233xf), 1-chloro-3,3,3-trifluoropropene (HFO-1233xf), 1-chloro-3,3,3-trifluoropropene (HFC ... Other fluorocarbons that may be present in the stream include 3,3,3-trifluoropropene (HFO-1233zd), 3-chloro-3,3-difluoropropene (HCFO-1242zf), 1-chloro-1-fluoroethane (HCFC-151a), 1-chloro-2-fluoroethane (HCFC-151), 1-chloro-3,3,3-trifluoropropane (HCFC-253fb), PCE, HCE / HCB, chloroethylene, 1,1,3-trichloro-1-propene (HCC-1240za), other tetra- or penta-fluoropropenes, and combinations thereof.

[0011] One process embodiment disclosed herein includes subjecting an HFC-254fb-containing stream to distillation in a first distillation column under boiling conditions to provide sufficient HF to form an azeotropic or near-azeotropic mixture of HFC-254fb and HFO-1243zf with HF. The process also includes forming a first (overhead) distillate stream comprising a mixture of HFC-254fb, HFO-1243zf, and sufficient HF such that 254fb / HF and HFO-1243zf / HF azeotropes and near-azeotropes are formed, and forming a first underside stream of HF essentially free of HFO-1243zf and HFC-254fb. The first distillate stream is separated into an HF-enriched stream and an HFC-254fb-enriched stream, which are further processed in a second distillation column to form a second distillate stream and a second bottoms stream, which are subsequently distilled in a third distillation column to form an HFO-1243zf and an HFC-254fb stream essentially free of HF.

[0012] The process further includes forming a second distillate stream of HFC-254fb, HFO-1243zf, and HF to form an azeotropic or near-azeotropic composition, e.g., HFC-254fb / HF and HFO-1243zf / HF, and forming a second understream of HFC-254fb and HFO-1243zf essentially free of HF from the second distillation column.

[0013] In certain embodiments, the second bottoms stream can be distilled by standard distillation techniques in a third distillation column (not shown) to form an HFC-254fb stream that is essentially free of HFO-1243zf.

[0014] In another embodiment, the present disclosure provides an azeotropic or near-azeotropic composition comprising 1,1,1,3-tetrafluoropropane (HFC-254fb), 3,3,3-trifluoropropene (HFO-1243zf), and hydrogen fluoride (HF), e.g., a mixture of HFC-254fb / HF and HFO-1243zf / HF azeotropes or near-azeotropes.

[0015] In another embodiment, the present invention provides an azeotropic or near-azeotropic composition comprising 1,1,1,3-tetrafluoropropane (HFC-254fb) and hydrogen fluoride (HF).

[0016] In one particular aspect of this embodiment, the present invention provides a composition comprising about 18.7 mol % HFC-254fb and about 81.3 mol % HF at a temperature of about 30° C. and having a vapor pressure of about 22.5 psia (169 kPa).

[0017] In another particular aspect of this embodiment, the present invention provides a composition comprising: i) an azeotropic or near-azeotropic composition comprising 1,1,1,3-tetrafluoropropane (HFC-254fb) and HF; and one or more of ii) HFO-1242zf and iii) HFO-1243zf.

[0018] In one aspect of the invention, the process stream contains a sufficient amount of HF, meaning a molar excess of HF relative to the organic content of the product stream, such that there is enough HF to remove all organics as an azeotrope or near-azeotrope in the first distillate.

[0019] In one embodiment of the present invention, the process stream comprises a composition comprising a mixture of two azeotropic or near-azeotropic mixtures, HFC-254fb / HF and HFO-1243zf / HF. In this embodiment, HF is present in an amount sufficient to form both an azeotrope or near-azeotrope, the distillate comprises both an azeotrope or near-azeotrope, and the bottom stream comprises HF essentially free of HFC-254fb and HFO-1243zf. Because HFC-254fb has a higher boiling point than HF, the HFC-254fb / HF azeotropic or near-azeotropic composition can be used to separate HFC-254fb.

[0020] Other features and advantages of any one or more of the embodiments described herein will be apparent from the following detailed description and claims.

[0021] The various embodiments of the invention can be used alone or in combination with each other. The foregoing general description and the following detailed description are exemplary and explanatory only and are not limiting of the invention, as defined in the appended claims. [Brief explanation of the drawings]

[0022] To facilitate understanding of the concepts presented herein, embodiments are illustrated in the accompanying drawings. [Figure 1] Illustrates an embodiment of azeotropic distillation for separating HFC-254fb from a mixture containing HFC-254fb, HFO-1243zf, and HF.

[0023] Those skilled in the art will appreciate that objects in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale, for example, the dimensions of some of the objects in the figures may be exaggerated relative to other objects to help improve understanding of the embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0024] Described herein is a process for separating HFC-254fb, HFO-1243zf, and HF from a composition comprising HFC-254fb, HFO-1243zf, and HF. The process takes advantage of the unexpected formation of an azeotropic or near-azeotropic composition of HFC-254fb and HF. Because HFC-254fb surprisingly forms a low-boiling azeotrope or near-azeotrope with HF, these mixtures can be used to produce HF essentially free of HFC-254fb and HFO-1243zf in a single distillation, even though HFC-254fb has a higher boiling point than HF and HFO-1243zf has a lower boiling point than HF.

[0025] The processes disclosed herein generally include the steps of subjecting a composition comprising HFC-254fb, HFO-1243zf, and HF to a distillation step to form an azeotropic or near-azeotropic composition comprising HFC-254fb and HF, and forming a distillate composition comprising HF, HFC-254fb, and HFO-1243zf, which may also include mixtures of azeotropic or near-azeotropic compositions, e.g., HFC-254fb / HF and HFO-1243zf / HF, and forming a bottoms composition comprising HF essentially free of either HFC-254fb or HFO-1243zf.

[0026] Described herein are azeotrope and azeotrope-like (used interchangeably herein with "near-azeotrope") compositions comprising HFC-254fb and HF, alone or in admixture with the HFO-1243zf / HF azeotrope.

[0027] DETAILED DESCRIPTION OF THE INVENTION Described herein are azeotrope and azeotrope-like compositions comprising HFC-254fb and HF, more particularly HFC-254fb / HF azeotropes or near-azeotropes.

[0028] Described herein are compositions comprising an HFC-254fb / HF azeotrope or near-azeotrope, alone or in admixture with an HFO-1243zf / HF azeotrope or near-azeotrope.

[0029] Azeotrope and azeotrope-like compositions suitable for separating HFC-254fb are also described herein.

[0030] Azeotropes and azeotrope-like compositions that are separated are also described herein.

[0031] In some embodiments, the composition comprising HFC-254fb, HFO-1243zf, and HF is a process stream.

[0032] In some embodiments, the composition being separated contains additional HFC-254fb or HF beyond the amount necessary to form an azeotrope or azeotrope-like composition comprising HFC-254fb / HF and optionally HFO-1243zf / HF.

[0033] Before going into the details of the embodiments described below, some terms will be defined or clarified.

[0034] An "azeotrope" composition refers to a constant-boiling liquid mixture of two or more substances that behaves as a single substance. One way to characterize an azeotropic composition is when the vapor produced by partial evaporation or distillation of a liquid has the same composition as the liquid from which it was evaporated or distilled (i.e., the mixture is distilled / refluxed without a change in composition). Constant-boiling compositions are characterized as azeotropic because they exhibit a maximum or minimum boiling point compared to non-azeotropic mixtures of the same components. Azeotropic compositions are also characterized by a minimum or maximum vapor pressure of the mixture relative to the vapor pressure of each undiluted component at a constant temperature. For binary systems such as HF and HFC-254fb, the presence of a maximum or minimum pressure as the composition changes in a PTx measurement is sufficient to indicate the presence of an azeotrope.

[0035] An "azeotropic" composition refers to a constant-boiling liquid mixture of two or more substances that behaves as a single substance. In general, an azeotrope is a phenomenon in which a composition contains two or more molecular species such that the relative volatility between the components of any binary pair is uniform. That is, the composition of a boiling liquid mixture that exhibits an azeotropy is identical to the vapor phase that is produced.

[0036]

number

[0037] Furthermore, the temperature of a boiling mixture, which exhibits an azeotropic mixture, remains constant at a constant pressure. A system is azeotropic if it can be distilled (or condensed) without a change in composition. The concept of a system exhibiting "azeotrope-like" or "near-azeotropic" is commonly known as a system that is sufficiently close to azeotropy that the liquid and vapor phases at phase equilibrium are very similar in composition and the boiling temperature increases only slightly during the boiling process. Thus, all relative volatilities for all binary pairs i to j in the system in the above equation are very close to unity. Thus, one way to characterize an azeotropic composition is that the vapor produced by partial evaporation or distillation of a liquid has the same composition as the liquid from which it was evaporated or distilled (i.e., the mixture can be distilled / refluxed without a change in composition). Constant-boiling compositions are characterized as azeotropic because they exhibit a maximum or minimum boiling point compared to non-azeotropic mixtures of the same components. Azeotropic compositions are also characterized by the minimum or maximum value of the vapor pressure of the mixture relative to the vapor pressure of each undiluted component at a constant temperature.

[0038] An "azeotrope-like" composition (sometimes referred to as a "near-azeotrope") refers to a constant-boiling or substantially constant-boiling liquid mixture of two or more substances that behaves as a single substance. One way to characterize an azeotrope-like or near-azeotropic composition is that the vapor produced by partial evaporation or distillation of a liquid has substantially the same composition as the liquid that was evaporated or distilled (i.e., a mixed distillate / reflux without a substantial change in composition). Another way to characterize an azeotrope-like or near-azeotropic composition is that the bubble point vapor pressure and dew point vapor pressure of the composition at a particular temperature are substantially the same, e.g., within 3 percent, as discussed below. Preferably, the terms "azeotrope-like composition" and "near-azeotropic composition" shall be understood to mean a composition in which the difference between the bubble point pressure ("BP") and dew point pressure ("DP") of the composition at a particular temperature is 5 percent or less, based on the bubble point pressure, i.e., [(BP-DP) / BP] x 100 ≤ 5; more preferably, the difference between the bubble point pressure ("BP") and dew point pressure ("DP") of the composition at a particular temperature is 3 percent or less, based on the bubble point pressure, i.e., [(BP-DP) / BP] x 100 ≤ 3. Azeotrope-like or near-azeotropic compositions may also be characterized by the area adjacent to the maximum or minimum vapor pressure in a plot of the vapor pressure of the composition at a given temperature as a function of the mole fraction of the components in the composition.

[0039] For azeotropic compositions, there is usually some range of compositions around the azeotropic point, with the highest boiling point azeotrope having a higher boiling point at a particular pressure than the pure components of the composition at that pressure and a lower vapor pressure at a particular temperature than the pure components of the composition at that temperature, and the lowest boiling point azeotrope having a lower boiling point at a particular pressure than the pure components of the composition at that pressure and a higher vapor pressure at a particular temperature than the pure components of the composition at that temperature. Boiling points and vapor pressures above or below the pure components are caused by unexpected intermolecular forces between the molecules of the composition, which can be a combination of repulsive and attractive forces such as van der Waals forces and hydrogen bonding.

[0040] It is recognized in the art that when an azeotropic liquid composition is subjected to boiling at various pressures, both the boiling point and the amount of each component of the azeotropic composition can change. Thus, an azeotropic composition can be defined in terms of the unique relationship that exists between the components, or in terms of the precise amount of each component that results in a composition characterized by a constant boiling point at a particular pressure. Azeotropic or azeotrope-like compositions of two or more compounds can be characterized by defining the composition as characterized by its boiling point at a given pressure, thereby providing a distinguishing feature without unduly limiting the scope of the invention with specific numerical compositions, which are limited, but only as accurate, by available analytical equipment.

[0041] It is recognized in the art that a system is defined as forming an azeotrope-like or near-azeotropic composition when its relative volatility approaches 1.0. Relative volatility is the ratio of the volatility of a first component to the volatility of a second component. The ratio of the mole fraction of a component in the vapor to the mole fraction of a component in the liquid is the component's volatility. To determine the relative volatility of any two compounds, a method known as the PTx method can be used. In this procedure, the total absolute pressure in a cell of known volume is measured at a constant temperature for various compositions of the two compounds. The use of the PTx method is described in detail in "Phase Equilibrium in Process Design," by Harold R. Null, Wiley-Interscience Publishers, 1970, pp. 124-126, which is incorporated herein by reference. These measurements can be converted to equilibrium vapor and liquid compositions in the PTx cell to represent liquid-phase nonideal systems using activity coefficient equation models, such as the Non-Random, Two-Liquid (NRTL) equation. For example, the use of activity coefficient equations, such as the NRTL equation, is described in detail in "The Properties of Gases and Liquids," 4th Edition, McGraw Hill, by Reid, Prausnitz, and Poling, pp. 241-387, and "Phase Equilibria in Chemical Engineering," Butterworth Publishers, 1985, by Stanley M. Walas, pp. 165-244. Both of the above references are incorporated herein by reference.

[0042] While not wishing to be bound by any theory or explanation, it is believed that the NRTL equation, in conjunction with PTx cell data, can adequately predict the relative volatility of the HFO-1243zf- and HFC-254fb-containing compositions of the present disclosure, and thus the behavior of these mixtures in multistage separation equipment, such as a distillation column. Furthermore, the existence of a maximum or minimum pressure in a binary system (such as HF and HFC-254fb) as the composition changes in a PTx measurement is sufficient to indicate the presence of an azeotrope. See, e.g., U.S. Pat. No. 8,486,293 and WO 2009105517, the disclosures of each of which are incorporated herein by reference, which rely on PTx data to predict mixtures, e.g., 254eb and 1243zf with HF.

[0043] The conditions and compositions of HF / HFC-254fb azeotropes according to the present invention as determined from PTx data are provided in Table A.

[0044] [Table 1]

[0045] Based on these findings, the present invention provides azeotropic or near-azeotropic compositions comprising, consisting of, or consisting essentially of from about 6.0 to about 25.6 mole percent HFC-254fb and from about 94.0 to about 74.4 mole percent HF.

[0046] In some embodiments, the present invention provides azeotropic or near-azeotropic compositions comprising, consisting of, or consisting essentially of from about 6.0 to about 25.6 mole percent HFC-254fb and from about 94.0 to about 74.4 mole percent HF, and having a boiling point of from about 80° C. at about 108 psia (744.6 kPa) to about −20° C. at about 3.0 psia (20.7 kPa).

[0047] As used herein, the term "azeotrope" is meant to refer to azeotropic, azeotrope-like, azeotropic and / or near-azeotropic compositions.

[0048] Process equipment for all processes disclosed herein, as well as associated supply lines, discharge lines, and related units, may be constructed from materials resistant to hydrogen fluoride. Typical materials of construction known in the art include carbon steel, stainless steel (especially austenitic), and well-known high-nickel alloys such as Monel® nickel-copper alloy, Hastelloy® nickel-based alloy, and Inconel® nickel-chromium alloy.

[0049] Azeotropic distillation refers to a process operated under conditions that result in the formation of one or more azeotropes or azeotrope-like compositions, thereby facilitating the separation of the components of the mixture. Azeotropic distillation can occur when only the components of the mixture to be separated are distilled, or when an entrainer is added that forms an azeotrope with one or more of the components of the original mixture. Entrainers that act in this manner, i.e., that form an azeotrope with one or more of the components of the mixture to be separated and thus facilitate the separation of those components by distillation, are more commonly referred to as azeotropic agents or azeotrope entrainers.

[0050] In conventional or azeotropic distillation, the overhead or distillate stream exiting the column can be condensed using a conventional reflux condenser. At least a portion of this condensed stream can be returned to the top of the column as reflux, and the remainder is recovered as product or for optional processing. The ratio of the condensed material returned to the top of the column as reflux to the material removed as distillate is commonly referred to as the reflux ratio. The compounds and entrainers exiting the column as distillate or distillation bottoms can then be passed to a stripper or second distillation column for separation using conventional distillation, or can be separated by other methods such as decantation. If desired, the entrainers can then be recycled back to the first distillation column for reuse. In some embodiments, the compositions and separation processes do not include, or are essentially free of, added entrainers.

[0051] The specific conditions that can be used to practice this invention depend on several parameters, including, among others, the diameter of the distillation column, the feed point, and the number of separation stages within the column. In some embodiments, the operating pressure of the distillation system can range from about 5 to about 500 psia (34 to 3450 kPa), and in other embodiments, from about 20 to about 400 psia (140 to 2760 kPa). Generally, increasing the reflux ratio increases the purity of the distillate stream, but reflux ratios generally range from about 1 / 1 to about 200 / 1. The temperature of the condenser located adjacent to the top of the column is typically sufficient to substantially completely condense the distillate exiting the top of the column, or as needed to achieve the desired reflux ratio by partial condensation.

[0052] As used herein, "essentially free" means that the composition contains less than about 100 ppm (on a molar basis), less than about 10 ppm, or less than about 1 ppm of the specified component. If the composition is essentially free of two or more components, the total concentration of those components is less than about 100 ppm, less than about 10 ppm, or less than about 1 ppm.

[0053] Hydrogen fluoride (HF, anhydrous) is a commercially available chemical or can be generated by methods known in the art.

[0054] As used herein, the terms "comprises," "comprising," "includes," "including," "has," "having," or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, article, or apparatus that includes a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent in such process, method, article, or apparatus. Furthermore, unless expressly stated to the contrary, "or" refers to an inclusive "or," not an exclusive "or." For example, a condition A or B is satisfied by any one of the following: A is true (or present) and B is false (or absent), A is false (or absent) and B is true (or present), and both A and B are true (or present).

[0055] The transitional phrase "consisting of" excludes any unspecified element, step, or ingredient. In the context of a claim, such a phrase closes the claim to including materials other than those recited, except for impurities normally accompanying the materials. When the phrase "consists of" appears within a clause in the body of a claim rather than immediately following the introductory section, the phrase is limited to only the elements recited in that clause and does not exclude other elements from the claim as a whole.

[0056] The transitional phrase "consisting essentially of" is used to define compositions, methods, and compositions that include materials, steps, mechanisms, components, or elements in addition to those literally disclosed, provided that these additionally included materials, steps, mechanisms, components, or elements do not materially affect the basic and novel characteristics of the claimed invention, particularly the mechanism of action for achieving any desired result of the inventive process. The term "consisting essentially of" has a meaning intermediate between "comprising" and "consisting of."

[0057] Additionally, the use of "a" or "an" is used to describe elements and components described herein. This is done merely for convenience and to give a general sense of the scope of the invention. This description should be interpreted to include one or at least one, and the singular also includes the plural unless it is clear that a different meaning is intended.

[0058] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of embodiments of the present disclosure, suitable methods and materials are described below. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety, unless a specific passage is cited. In case of conflict, the present specification, including definitions, will control. Furthermore, the materials, methods, and examples are illustrative only and are not intended to be limiting.

[0059] "Molar excess HF" means an amount of HF that exceeds the amount necessary to form an azeotropic or near-azeotropic mixture with the organic substance (HFC or HFO) present in the composition. The molar amount of HF varies as a function of the organic substances present in the separated composition and the separation conditions. Molar excess HF for a given composition is an amount of HF greater than the amount of HF required to form an azeotropic (or near-azeotropic) mixture for each organic compound in the composition. Refer to the following list of the amounts of HF required to form an azeotropic mixture with each of HFO-1243zf, HFC-254eb, and HFC-254fb at 100 psig, which can vary with pressure.

[0060]

Table 2

[0061] As illustrated above, the amount of HF required to form an azeotropic composition with an organic substance, such as HFO-1243zf, HFC-254eb, or HFC-254fb, increases from HFO-1243zf to HFC-254fb. In other words, more than twice as much HF is required to form an HFC-254fb / HF azeotropic or near-azeotropic composition compared to an HFO-1243zf / HF azeotropic or near-azeotropic composition. As shown in Table 1 above, the molar % content of HF in the azeotropic mixture increases from about 28% of HFO-1243zf at 100 psig to about 74% of HFC-254fb according to the relationship HFO-1243zf < HFC-254eb < HFC-254fb, which follows the expected order from the lowest boiling point to the highest boiling point of the organic components.

[0062] Thus, in some embodiments, to provide a bottoms stream that is free or essentially free of both HFO-1243zf and HFC-254fb, the amount of HF in the feed stream is at least equal to the amount of HF required for both the HFO-1243zf / HF and HFC-254fb / HF azeotropes or near-azeotropes. The HFO-1243zf / HF azeotrope can form in the absence of the HFC-254fb / HF azeotrope if the amount of HF in the feed stream is less than the amount of HF in the HFO-1243zf / HF azeotrope. However, under these conditions, the bottoms stream from the distillation column contains HFC-254fb. When the HFC-254fb / HF azeotrope is present, a HF feed content greater than the amount of HF in the HFO-1243zf / HF azeotrope but less than the amount of HF in the HFC-254fb / HF azeotrope will still result in a bottoms stream containing HFC-254fb. The HF-containing bottom stream can be free or essentially free of HFO-1243zf and HFC-254fb only if the amount of HF in the feed stream is greater than the total amount of HF in both the HFO-1243zf / HF and HFC-254fb / HF azeotropes or near-azeotropes. Thus, a 100 psig process stream containing equimolar amounts of three organic azeotropes, e.g., 1 mole of each, requires at least 3.97 moles of HF to be available for the azeotrope to form. Varying the pressure will change the amount of HF required for the three azeotropes.

[0063] In some embodiments, the separation process is part of a general process for producing 3,3,3-trifluoropropene (HFO-1243zf, CFCH=CH). In some embodiments, the production of HFO-1243zf is part of a general process for producing 2,3,3,3-tetrafluoropropene (HFO-1234yf; CFCF=CH). In some embodiments, the separation process separates a process stream that is a reaction product stream of a reaction process to produce HFO-1243zf. In some embodiments, the reaction process produces HFO-1243zf by the fluorination of 1,1,1,3-tetrachloropropane (HCC-250fb; CClCHCHCl).

[0064] HFO-1243zf can be made by the fluorination of HCC-250fb with HF over a fluorination catalyst such as a chromium fluoride / alumina or chromium oxide catalyst. HCC-250fb can be made by the addition reaction of carbon tetrachloride and ethylene by processes known in the art, such as those described in U.S. Pat. Nos. 4,605,802 and 5,705,779, which are incorporated herein by reference in their entireties.

[0065] The reaction product stream from the fluorination of HCC-250fb with HF may contain, in addition to excess HF and the HFO-1243zf product, HFC-254fb and other intermediate products, such as 3-chloro-3,3-difluoropropene (HCFO-1242zf; CF2Cl-CH=CH2), dichlorodifluoromethane (CFC-12; CCl2F2), chlorotrifluoromethane (CFC-13; CClF3), 1,1,1-trifluoroethane (HFC-143a; CF3-CH3), 1,1,1,2,2-pentachloro-2-fluoroethane (HCFC-111; CCl3CCl2F), 1,2-dichloro-3,3,3-trifluoropropane (HCFC-243db; CF3 CHClCHCl); 2-chloro-1,1,1-trifluoropropane (HCFC-253db; CF3-CHCl-CH3), 3-chloro-1,1,1-trifluoropropane (HCFC-253fb; CF3-CH2-CH2Cl), 1,1,1,2-tetrafluoropropane (HFC-254eb; CF3-CHF-CH3), 1,1,1-trifluoropropane (HFC-263fb; CF3CH2CH3), 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf; CF3-CCl=CH2), 1,2-difluoro-3,3,3-trifluoropropene 2,3-dichloro-3,3-difluoropropene (HCFO-1232xf; CClFCCl=CH); 2,2-chloro-2-fluoropropene (CClFCH=CH; HCFC-1241zf), 1-chloro-3,3,3-trifluoropropene (HCFO-1233zd; CF-CH=CHCl), isomers of trichloropropene (HCFO-1240; CHCl), 1,1,2,2-tetrachloroethylene (PCE; CCl=CCl), or combinations thereof.

[0066] HFO-1243zf is known to form a binary azeotropic composition with HF, as disclosed in International Application Publication No. 2009 / 105517, the disclosure of which is incorporated herein by reference in its entirety. The azeotropic composition contains about 72.0 mol% HFO-1243zf and about 28.0 mol% HF at 29.8°C and 106.6 psia (735 kPa). Additionally, the azeotropic composition contains about 76.2 mol% HFC1243zf and about 23.8 mol% HF at 79.7°C and 363 psia (2503 kPa).

[0067] Surprisingly, HFC-254fb was also found to form a binary azeotrope with HF.

[0068] For purposes of this disclosure, an "effective amount" is defined as the amount of each component of the compositions of the present invention that, when combined, forms an azeotrope or azeotrope-like composition. This definition includes the amounts of each component, which may vary depending on the pressure applied to the composition, so long as the azeotrope or azeotrope-like composition continues to exist at different pressures (although the boiling points may differ). Thus, an effective amount includes the amount (which may be expressed, for example, by weight percent) of each component of the compositions of the present disclosure that forms an azeotrope or azeotrope-like composition at temperatures or pressures other than those described herein.

[0069] For the purposes of this disclosure, azeotropes or constant boiling points are also intended to mean essentially azeotropes or essentially constant boiling points. In other words, these terms include not only the true azeotropes described above, but also other compositions containing the same components in different proportions that are true azeotropes at other temperatures and pressures, as well as equivalent compositions that are part of the same azeotrope system and are azeotrope-like in their properties. As is well recognized in the art, there is a range of compositions containing the same components as azeotropes that not only exhibit essentially equivalent properties for refrigeration and other applications, but also exhibit essentially equivalent properties to true azeotropic compositions with respect to constant boiling point properties or the tendency not to separate or fractionate upon boiling.

[0070] Depending on the conditions selected, it is possible to actually characterize a constant-boiling mixture, which can appear under many guises, by any of several criteria. A composition can be defined as an azeotrope of A, B, C (and D). This is because the very term "azeotrope" is simultaneously definitive and restrictive, requiring effective amounts of A, B, C (and D) for this unique composition to be a constant-boiling composition. It is well known to those skilled in the art that at different pressures, the composition of a given azeotrope will vary, at least to some extent, and that changes in pressure will change the boiling point temperature, at least to some extent. Thus, an azeotrope of A, B, C (and D) represents a unique type of relationship, but with a composition that varies with temperature and / or pressure. Therefore, a range of compositions, rather than a fixed composition, is often used to define an azeotrope. While a composition may be defined as a particular weight percent or mole percent relationship of A, B, C (and D), it is recognized that such specific values ​​represent only one particular relationship, and that in fact a series of such relationships represented by A, B, C (and D) actually exist for a given azeotrope that varies with the influence of pressure. Azeotropes of A, B, C (and D) can be characterized by defining the composition as an azeotrope characterized by its boiling point at a given pressure, thereby providing an identifying characteristic without unduly limiting the scope of the invention with specific numerical compositions, which are limited only as accurately as available analytical equipment.

[0071] When two azeotropes exist, the composition can be defined as an azeotrope of A, which is HFO-1243zf / HF, and B, which is HFC-254fb / HF, or vice versa, precisely because the term "azeotrope" is simultaneously definitive and restrictive, requiring effective amounts of A and B for this unique composition to be a constant-boiling composition. It is well known to those skilled in the art that at different pressures, the composition of a given azeotrope will vary, at least to some extent, and that changes in pressure will also change the boiling point temperature, at least to some extent. Thus, an azeotrope of A and B represents a unique type of relationship, but with a composition that varies with temperature and / or pressure. Thus, a range of compositions, rather than a fixed composition, is often used to define an azeotrope. While a composition can be defined as a specific weight or mole percent relationship between A and B, it is recognized that such specific values ​​represent only one particular relationship, and that in reality, a series of such relationships represented by A and B actually exist for a given azeotrope, varying with the influence of pressure. Azeotropes of A and B can be characterized by defining the composition as an azeotrope characterized by its boiling point at a given pressure, thereby providing a distinguishing characteristic without unduly limiting the scope of the invention with specific numerical compositions, which are limited by, and only as accurate as, available analytical equipment.

[0072] The azeotrope or azeotrope-like compositions of the present invention can be prepared by any convenient method, including mixing or combining the desired amounts. One preferred method is to weigh the desired amounts of the components and then mix the components in a suitable container. Another preferred method is to form the azeotrope or azeotrope-like composition as the distillate stream of a distillation column.

[0073] It was unexpected that HFC-254fb would form azeotrope or azeotrope-like compositions with HF.

[0074] In some embodiments, a process for separating hydrogen fluoride (HF) from a composition (e.g., a process stream) comprising 1,1,1,3-tetrafluoropropane (HFC-254fb), 3,3,3-trifluoropropene (HFO-1243zf), and a molar excess of HF is provided. The process includes subjecting the process stream to distillation in a first distillation column under boiling conditions for an HFO-1243zf / HF azeotrope or near-azeotrope and an HFC-254fb / HF azeotrope or near-azeotrope. The process also includes forming a first distillate stream comprising an azeotrope- or near-azeotrope-forming composition of HFC-254fb / HF and HFO-1243zf / HF, and forming a first bottom stream of HF essentially free of HFC-254fb and HFO-1243zf from the first distillation column.

[0075] In some embodiments, the process of the above paragraph further comprises condensing, cooling, and decanting the first distillate stream to form an HF-enriched stream and an HFC-254fb-enriched stream, and recycling the HF-enriched stream to the first distillation column.

[0076] In some embodiments, the process of the above paragraph further comprises subjecting the HFC-254fb-enriched stream to distillation in a second distillation column under HFC-254fb / HF and HFO-1243zf / HF azeotropic or near-azeotropic boiling conditions, and forming a second distillate stream comprising an azeotropic or near-azeotropic composition of HFC-254fb / HF and HFO-1243zf / HF, and a second bottom stream of HFC-254fb and HFO-1243zf essentially free of HF from the second distillation column.

[0077] In some embodiments, the process further comprises subjecting the second bottoms stream to a third distillation column using known methods to form an HFC-254fb stream that is essentially free of HFO-1243zf.

[0078] In some embodiments, the process stream of any of the above paragraphs is a reaction product stream of a reaction process for producing HFO-1243zf by the fluorination of 1,1,1,3-tetrachloropropane (HCC-250fb) with HF.

[0079] In some embodiments, a process for separating 1,1,1,3-tetrafluoropropane (HFC-254fb) from an HFC-254fb-rich stream containing HFC-254fb, 3,3,3-trifluoropropene (HFO-1243zf), and hydrogen fluoride (HF) is provided. The process includes subjecting the HFC-254fb-rich stream to distillation in a second distillation column under boiling conditions of the HFC-254fb / HF and HFO-1243zf / HF azeotropes or near-azeotropes to form a second distillate overhead stream and a second bottoms stream. The second bottoms stream is then subjected to a third distillation column to form an HFC-254fb stream essentially free of HFO-1243zf.

[0080] In one embodiment, the disclosed composition is an azeotropic or near-azeotropic composition consisting essentially of 1,1,1,3-tetrafluoropropane (HFC-254fb) and hydrogen fluoride (HF).

[0081] In one embodiment, the disclosed composition is an azeotropic or near-azeotropic composition consisting essentially of from about 6.0 to about 25.6 mole percent HFC-254fb and from about 94.0 to about 74.4 mole percent HF. In one embodiment, the composition optionally further comprises at least one of 3-chloro-3,3-difluoro-1-propene (HCFO-1242zf) and HFO-1243zf.

[0082] In some embodiments, the disclosed compositions are azeotropic or near-azeotropic compositions consisting essentially of about 6.0 to about 25.6 mole percent HFC-254fb and about 94.0 to about 74.4 mole percent HF, and having a vapor pressure of about 3.0 psia (20.7 kPa) to about 108 psia (744.6 kPa) at a temperature of about −20° C. to about 80° C. In one embodiment, the composition optionally further comprises at least one of HCFO-1242zf and HFO-1243zf.

[0083] In one embodiment, the disclosed composition is an azeotropic or near-azeotropic composition consisting essentially of about 18.7 mol % HFC-254fb and about 81.3 mol % HF, having a vapor pressure of about 24.5 psia (169 kPa) at a temperature of about 30° C., and optionally including at least one of HCFO-1242zf and HFO-1243zf.

[0084] In one embodiment, the compositions disclosed herein are azeotropes or near-azeotropes consisting essentially of 1,1,1,3-tetrafluoropropane (HFC-254fb) and HF, and optionally at least one of HCFO-1242zf and HFO-1243zf.

[0085] In some embodiments, a process for separating 1,1,1,3-tetrafluoropropane (HFC-254fb) from a process stream containing HFC-254fb, HFO-1243zf, and a molar excess of HF is provided. The process includes subjecting the process stream to distillation in a first distillation column under boiling conditions to form an azeotropic mixture of HFC-254fb and HFO-1243zf with HF, using a molar excess of HF sufficient to form both azeotropes. The process also includes forming a first distillate stream containing HFC-254fb, HFO-1243zf, and a sufficient amount of HF to form azeotropic or near-azeotropic compositions between HFC-254fb and HF, and between HFO-1243zf and HF, and a first bottoms stream of HF essentially free of HFC-254fb and HFO-1243zf from the first distillation column.

[0086] In some embodiments, the process comprises a product stream from the production of HFO-1243zf, for example, by the fluorination of 1,1,1,3-tetrachloropropane (HCC-250fb) with HF.

[0087] In some embodiments, the process stream of any of the above paragraphs further comprises 3-chloro-3,3-difluoro-1-propene (HCFO-1242zf).

[0088] In some embodiments, the first distillate stream and the second distillate stream of any of the above paragraphs comprise an azeotropic or near-azeotropic composition comprising from about 6.0 to about 25.6 mole percent HFC-254fb and from about 94.0 to about 74.4 mole percent HF.

[0089] In some embodiments, the first distillate stream and the second distillate stream of any of the above paragraphs comprise an azeotropic or near-azeotropic composition comprising from about 6.0 to about 25.6 mole percent HFC-254fb and from about 94.0 to about 74.4 mole percent HF, and having a vapor pressure of from about 3.0 psia (20.7 kPa) to about 108 psia (744.6 kPa) at a temperature of from about -20°C to about 80°C.

[0090] In some embodiments, the first distillate stream and the second distillate stream of any of the above paragraphs contain about 18.7 mol % HFC-254fb and about 81.3 mol % HF and have a vapor pressure of about 24.5 psia (169 kPa) at a temperature of about 30° C.

[0091] In some embodiments, a composition is provided that includes an azeotrope or near-azeotrope of 1,1,1,3-tetrafluoropropane (HFC-254fb) / HF and 3,3,3-trifluoropropene (HFO-1243zf) / HF.

[0092] In some embodiments, the composition comprises from about 6.0 to about 25.6 mole percent HFC-254fb and from about 94.0 to about 74.4 mole percent HF.

[0093] In some embodiments, the composition comprises from about 6.0 to about 25.6 mole percent HFC-254fb and from about 94.0 to about 74.4 mole percent HF, and has a vapor pressure of from about 3.0 psia (20.7 kPa) to about 108 psia (744.6 kPa) at a temperature of from about -20°C to about 80°C.

[0094] In some embodiments, the composition comprises about 18.7 mole % HFC-254fb and about 81.3 mole % HF and has a vapor pressure of about 24.5 psia (169 kPa) at a temperature of about 30°C.

[0095] In some embodiments, the compositions described herein further comprise 3-chloro-3,3-difluoro-1-propene (HCFO-1242zf). [Example]

[0096] Referring to Example 1, illustrated in Figure 1, a process stream 100 containing HFC-254fb and HFO-1243zf and a molar excess of HF is fed to a first distillation column 110. This first column 110 is operated under conditions suitable to approach the boiling conditions of the HFC-254fb and HFO-1243zf azeotrope with HF. Because HF is fed to first column 110 in excess of the amount required to form the azeotrope with HFC-254fb and HFO-1243zf, the excess HF, essentially free of HFC-254fb and HFO-1243zf, is recovered as a bottom portion of first column 110, as a first bottoms stream 120. An overhead stream 130, rich in HFC-254fb and HFO-1243zf, is fed to a condenser 140 and removed as a condensed stream 150. Stream 150 is split into streams 190 and 200. Stream 190 is returned to column 110 as reflux, and stream 200 is further processed, for example, distilled in a second distillation. Details for operating the system of Figure 1 are identified in Table 2.

[0097] [Table 3]

[0098] In separation processes described herein that include two or more distillation columns, the distillation columns may all operate at the same pressure and / or temperature, or at different pressures and / or temperatures.

[0099] When the composition being separated is a reaction product stream formed by the fluorination of HFC-254fb with HF, it is desirable to recycle any unreacted HFC-254fb back to the reactor so that it can be converted to HFO-1243zf. However, the HFO-1243zf needs to be removed from the unreacted HFC-254fb before being recycled so as not to inhibit the equilibrium reaction. It is also necessary to remove HF from the HFO-1243zf so that it can be used as a reagent in another reaction, as a refrigerant, or in other applications.

[0100] Other embodiments forming a first distillate stream sufficient to form an azeotropic or near-azeotropic composition comprising HFC-254fb and HF, and a first underflow of HF from a first distillation column containing less than 100 ppm HFC-254fb and HFO-1243zf.

[0101] forming a first distillate stream sufficient to form an azeotropic or near-azeotropic composition comprising HFC-254fb and HF, and a first bottoms stream of HF from a first distillation column containing less than 10 ppm HFC-254fb and HFO-1243zf.

[0102] forming a first distillate stream sufficient to form an azeotropic or near-azeotropic composition comprising HFC-254fb and HF, and a first bottoms stream of HF from a first distillation column containing less than 1 ppm HFC-254fb and HFO-1243zf.

[0103] forming a first distillate stream sufficient to form an azeotropic or near-azeotropic composition comprising HFC-254fb / HF and HFO-1243zf / HF, and a first HF underflow from a first distillation column containing less than 100 ppm HFC-254fb and HFO-1243zf.

[0104] forming a first distillate stream sufficient to form an azeotropic or near-azeotropic composition comprising HFC-254fb / HF and HFO-1243zf / HF, and a first HF underflow from a first distillation column containing less than 10 ppm HFC-254fb and HFO-1243zf.

[0105] forming a first distillate stream sufficient to form an azeotropic or near-azeotropic composition comprising HFC-254fb / HF and HFO-1243zf / HF, and a first HF bottoms stream containing less than 1 ppm HFC-254fb and HFO-1243zf from a first distillation column.

[0106] It should be noted that not all of the operations or embodiments described above in the general description are required, some of the specific operations may not be required, and one or more additional operations may be performed in addition to the operations described. Furthermore, the order in which the operations are listed is not necessarily the order in which they are performed.

[0107] In the foregoing specification, the concepts of the present invention have been described with reference to specific embodiments. However, those skilled in the art will recognize that various modifications and changes can be made without departing from the scope of the invention as set forth in the following claims. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense, and all such modifications are intended to be included within the scope of the present invention.

[0108] Benefits, other advantages, and solutions to problems have been described above with reference to specific embodiments. However, these benefits, advantages, solutions to problems, and any features that may produce or make more apparent any benefit, advantage, or solution are not to be construed as essential, required, or essential features in any or all of the claims.

[0109] It should be understood that certain features that are, for clarity, described herein in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features that are, for brevity, described in the context of a single embodiment, may also be provided separately or in any subcombination. Further, references to values ​​stated in ranges include each and every value within that range.

Claims

1. 1. A process for separating hydrogen fluoride (HF) from a process stream containing 1,1,1,3-tetrafluoropropane (HFC-254fb), 3,3,3-trifluoropropene (HFO-1243zf), and a molar excess of HF, comprising: subjecting said process stream to distillation in a first distillation column under boiling conditions of an HFC-254fb and HFO-1243zf azeotrope with HF; forming from said first distillation column a first distillate stream comprising an azeotrope or near-azeotrope of HFC-254fb / HF and HFO-1243zf / HF, and a first bottom stream of HF essentially free of HFC-254fb and HFO-1243zf; The process includes:

2. 10. The process of claim 1 further comprising converting said first distillate stream into an HF-rich stream and an HFC-254fb-rich stream.

3. 3. The process of claim 2, wherein said converting step comprises cooling said first distillate stream to form said HF-rich stream and said HFC-254fb-rich stream.

4. 4. The process of claim 3, further comprising feeding the HF-enriched stream to the first distillation column.

5. 3. The process of claim 2, wherein said converting step comprises at least one of condensing said first distillate stream to form said HF-rich stream and said HFC-254fb-rich stream, and cooling said first distillate stream to form said HF-rich stream and said HFC-254fb-rich stream.

6. 10. The process of claim 1, wherein the process stream is a reaction product stream of a reaction process for producing HFO-1243zf by fluorination of 1,1,1,3-tetrachloropropane (HCC-250fb) with HF.

7. 10. The process of claim 1, wherein the process stream further comprises 3-chloro-3,3-difluoro-1-propene (HCFO-1242zf).

8. 10. The process of claim 1, wherein said first distillate stream and said second distillate stream comprise from about 6.0 to about 25.6 mole % HFC-254fb and from about 94.0 to about 74.4 mole % HF.

9. 10. The process of claim 1, wherein the first distillate stream and the second distillate stream comprise from about 6.0 to about 25.6 mole % HFC-254fb and from about 94.0 to about 74.4 mole % HF and have a vapor pressure of from about 3.0 psia (20.7 kPa) to about 108 psia (744.6 kPa) at a temperature of from about -20°C to about 80°C.

10. 10. The process of claim 1, wherein the first distillate stream and the second distillate stream comprise about 18.7 mole % HFC-254fb and about 81.3 mole % HF and have a vapor pressure of about 24.5 psia (169 kPa) at a temperature of about 30°C.

11. 1. A process for separating 1,1,1,3-tetrafluoropropane (HFC-254fb) from a stream containing HFC-254fb, 3,3,3-trifluoropropene (HFO-1243zf), and hydrogen fluoride (HF), comprising: subjecting said stream to distillation in a first distillation column under boiling conditions of HFC-254fb / HF and HFO-1243zf / HF azeotropes; forming from said first distillation column a first distillate stream comprising an azeotropic or near-azeotropic composition of HFC-254fb / HF and HFO-1243zf / HF, and a first understream of HFC-254fb and HFO-1243zf essentially free of HF; subjecting said first bottoms stream to a second distillation column to form an HFC-254fb stream essentially free of HFO-1243zf; The process includes:

12. 12. The process of claim 11, wherein the stream is an HFC-254fb-enriched stream.

13. 13. The process of claim 12, wherein the HFC-254fb-enriched stream further comprises 3-chloro-3,3-difluoro-1-propene (HCFO-1242zf).

14. 12. The process of claim 11, wherein the first distillate stream comprises from about 6.0 to about 25.6 mol % HFC-254fb and from about 94.0 to about 74.4 mol % HF.

15. 12. The process of claim 11, wherein the first distillate stream comprises from about 6.0 to about 25.6 mole % HFC-254fb and from about 94.0 to about 74.4 mole % HF and has a vapor pressure of from about 3.0 psia (20.7 kPa) to about 108 psia (744.6 kPa) at a temperature of from about -20°C to about 80°C.

16. 12. The process of claim 11, wherein the first distillate stream comprises about 18.7 mole % HFC-254fb and about 81.3 mole % HF and has a vapor pressure of about 24.5 psia (169 kPa) at a temperature of about 30°C.

17. An azeotropic or near-azeotropic composition comprising 1,1,1,3-tetrafluoropropane (HFC-254fb) and hydrogen fluoride (HF).

18. 18. The composition of claim 17, wherein the composition comprises from about 6.0 to about 25.6 mole % HFC-254fb and from about 94.0 to about 74.4 mole % HF.

19. 18. The composition of claim 17, wherein the composition comprises from about 6.0 to about 25.6 mole % HFC-254fb and from about 94.0 to about 74.4 mole % HF and has a vapor pressure of from about 3.0 psia (20.7 kPa) to about 108 psia (744.6 kPa) at a temperature of from about -20°C to about 80°C.

20. 18. The composition of claim 17, wherein the composition comprises about 18.7 mole percent HFC-254fb and about 81.3 mole percent HF and has a vapor pressure of about 24.5 psia (169 kPa) at a temperature of about 30°C.

21. A composition comprising HFC-254fb, 1,1,1-trifluoropropene (HFO-1243zf), and hydrogen fluoride (HF).

22. 22. The composition of claim 21, further comprising 3-chloro-3,3-difluoro-1-propene (HCFO-1242zf).

23. A composition comprising: i) an azeotropic or near-azeotropic composition comprising 1,1,1,3-tetrafluoropropane (HFC-254fb) and hydrogen fluoride (HF); ii) 1242zf; and iii) 1243zf.

24. passing a process stream comprising 1,1,1,3-tetrafluoropropane (HFC-254fb), 3,3,3-trifluoropropene (HFO-1243zf), and HF through a distillation column; controlling the HF content of said process stream to form azeotropic and near-azeotropic HFC-254fb / HF compositions; separating at least HFC-254fb; The separation process includes:

25. 25. The separation process of claim 24, wherein said azeotropic and near-azeotropic HFC-254fb / HF compositions are used to separate HFC-254fb.

26. 25. The separation process of claim 24, further comprising recovering an HF stream essentially free of HFC-254fb.

27. 25. The process of claim 24, further comprising recovering an HF stream essentially free of at least one of HFO-1243zf and HFC-254fb.

28. 28. The process of any one of claims 1, 11, 26, or 27, essentially free of at least one of HF, HFO-1243zf, and HFC-254fb at less than about 100 ppm (on a molar basis), less than about 10 ppm, or less than about 1 ppm.

29. An azeotropic or near-azeotropic composition consisting essentially of 1,1,1,3-tetrafluoropropane (HFC-254fb) and hydrogen fluoride (HF).

30. 30. The composition of claim 29, wherein the composition consists essentially of from about 6.0 to about 25.6 mole % HFC-254fb and from about 94.0 to about 74.4 mole % HF.

31. 30. The composition of claim 29, wherein the composition consists essentially of from about 6.0 to about 25.6 mole % HFC-254fb and from about 94.0 to about 74.4 mole % HF and has a vapor pressure of from about 3.0 psia (20.7 kPa) to about 108 psia (744.6 kPa) at a temperature of from about -20°C to about 80°C.

32. 30. The composition of claim 29, wherein the composition consists essentially of about 18.7 mole % HFC-254fb and about 81.3 mole % HF and has a vapor pressure of about 24.5 psia (169 kPa) at a temperature of about 30°C.

33. A composition comprising the composition of claim 29 and 3-chloro-3,3-difluoro-1-propene (HCFO-1242zf).

34. A composition comprising the composition of claim 20 and HCFO-1243zf.

35. A composition consisting essentially of: i) an azeotropic or near-azeotropic composition comprising 1,1,1,3-tetrafluoropropane (HFC-254fb) and hydrogen fluoride (HF); ii) 1242zf; and iii) 1243zf.

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