PROCESS FOR PRODUCING (Z)-1,1,1,4,4,4-HEXAFLUORO-2-BUTENE AND INTERMEDIATES

Abstract

A process for producing (Z)-1,1,1,4,4,4-hexafluoro-2-butene (Z-1336mzz) is described. The process uses readily available halogenated starting materials, including 1,1,1-trichloro-2,2,2-trifluoroethane (CFC-113a) and carbon tetrachloride.

Description

PROCESS FOR PRODUCING (Z)-1,1,1,4,4,4-HEXAFLUORO-2-BUTENE AND INTERMEDIATES FIELD OF INVENTION This description relates to processes used to produce (Z)-1,1,1,4,4,4-hexafluoro-2-butene (Z-1336mzz), and useful intermediates in such production. In particular, this description relates to a process for producing (Z)-1,1,1,4,4,4-hexafluoro-2-butene (Z-1336mzz) from readily available halogenated alkanes. BACKGROUND OF THE INVENTION The fluorocarbon industry has been working for decades to find replacement refrigerants to phase out ozone-depleting chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) as a result of the Montreal Protocol. The solution for many applications has been the commercialization of hydrofluorocarbon (HFC) compounds for use as refrigerants, solvents, fire extinguishing agents, blowing agents, and propellants. These newer compounds, such as the HFC refrigerants HFC-134a and HFC-125, which are the most widely used at present, have zero ozone depletion potential and are therefore not subject to the current regulatory phase-out under the Montreal Protocol. ud iy Ref. 336270 In addition to ozone depletion concerns, global warming is another environmental concern in many of these applications. Therefore, there is a need for compositions that meet low ozone depletion standards and have a low global warming potential (GWP). Certain hydrofluoroolefin compositions are believed to meet both objectives. Consequently, there is also a need for cost-effective manufacturing processes that yield these compositions. (Z)-1,1,1,4,4,4-hexafluoro-2-butene (Z-1336mzz) is a hydrofluoroolefin used in refrigerants, heat transfer compositions, thermodynamic cycle working fluids (e.g., heating or cooling cycles), aerosol propellants, blowing agents, solvents, cleaning agents, carrier fluids, displacement drying agents, abrasive polishing agents, polymerization media, foaming agents for polyolefins and polyurethane, gaseous dielectrics, power cycle working fluids, fire extinguishing agents, and fire suppression agents in liquid or gaseous form. The GWP for cis-HFO-1336mzz was calculated from the atmospheric lifetime to be < 10 for a 100-year time horizon. uo ia There is a need in this technique for a process that can produce (Z)-1,1,1,4,4,4-hexafluoro-2-butene (Z-1336mzz) efficiently and economically. SUMMARY OF THE INVENTION This description provides processes for the production of the hydrofluoroolefin Z1,1,1,4,4,4-hexafluoro-2-butene (Z-CF3CH=CHCF3, Z-1336mzz) and useful intermediates in its production. The processes described herein provide cost-effective synthetic routes to Z-1336mzz from CF3CCl3 and CH2=CC12 or CC14 and CF3C1=CH2. In one embodiment, a process for producing a mixture of products comprising 1,1,1,3,3-pentachloro-4,4,4-trifluorobutane (CC13CH2CHC1CF3, 333jfa) comprises contacting a halogenated alkane with an olefin in the presence of a mononitrile and a catalyst comprising copper(II) chloride, wherein the halogenated alkane is selected from 1,1,1-trichloro-2,2,2-trifluoroethane (CF3CCI3, 113a) and carbon tetrachloride (CCl4), provided that when the halogenated alkane is 1,1,1-trichloro-2,2,2-trifluoroethane, the olefin is vinylidene chloride (CH2=CC12, VDC) and when the halogenated alkane is carbon tetrachloride, the olefin is 2-chloro -3,3,3trifluoropropene (CF3CC1=CH2, 1233xf). In one embodiment, a process comprises contacting 333jfa, produced as described above, with hydrogen fluoride (HF) in the gas phase or in the liquid phase, in the presence of a catalyst of ud 1 and fluorination under conditions to produce a mixture of products comprising 2,2-dichloro-1,1,1,4,4,4-hexafluorobutane (CF3CCI2CH2CF3, 336mfa). In one embodiment, a process comprises contacting 336mfa, produced as described above, with base and optionally a phase transfer catalyst, to produce a mixture of products comprising 1,1,1,4,4,4hexafluorobutyne. In one embodiment, 1,1,1,4,4,4-hexafluoro-2-butyne is reacted with hydrogen and a hydrogenation catalyst to produce a mixture of products comprising the analogue of Zl,1,1,4,4,4-hexafluoro-2-butene (Z-1336mzz). The present description provides a process for the production of Z1,1,1,4,4,4-hexafluoro-2-butene comprising (a) contacting a halogenated alkane with an olefin in the presence of a mononitrile and a catalyst comprising copper(II) chloride, wherein the halogenated alkane is selected from 1,1,1-trichloro-2,2,2-trifluoroethane and carbon tetrachloride, provided that when the halogenated alkane is 1,1,1-trichloro-2,2,2-trifluoroethane, the olefin is vinylidene chloride and when the halogenated alkane is carbon tetrachloride, the olefin is 2-chloro-3,3,3-trifluoropropene to produce a product mixture comprising 1,1,1,3,3-pentachloro-4,4,4-trifluorobutane; (a) contacting 1,1,1,3,3-pentachloro-4,4,4-trifluorobutane with hydrogen fluoride in the liquid phase or in the gas phase in the presence of a fluorination catalyst to produce a mixture of products comprising 2,2-dichloro-1,1,1,4,4,4-hexafluorobutane;(c) contacting 2,2-dichloro-1,1,1,4,4,4-hexafluorobutane with a base and a phase-transfer catalyst to produce a mixture of products comprising 1,1,1,4,4,4-hexafluoro-2-butyne; and (d) contacting 1,1,1,4,4,4-hexafluoro-2-butyne with hydrogen and a hydrogenation catalyst to produce a mixture of products comprising 1,1,4,4,4-hexafluoro-2-butene. In any of the above processes, the desired product can be recovered from the mixture of products comprising the desired product. The foregoing general description and the following detailed description are illustrative and explanatory only and do not limit the present description as defined in the appended claims. Other features and advantages of the processes described herein will become apparent from the following more detailed description of the preferred embodiments, taken in conjunction with this description. DETAILED DESCRIPTION OF THE INVENTION As used herein, the terms comprise, which comprises, include, which includes, has, which has, or any other variation thereof, encompass a non-exclusive inclusion. For example, a process, method, article, or apparatus comprising a list of elements is not necessarily limited to those elements but may include other elements not expressly stated or inherent in such process, method, article, or apparatus. Furthermore, unless expressly stated otherwise, "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 not present), A is false (or not present) and B is true (or present), and both A and B are true (or present). The transitional phrase "consists of" excludes any unspecified element, stage, or ingredient. If it appears in the claim, it would limit the claim to include materials other than those mentioned, except for impurities normally associated with them. When the phrase "consists of" appears in a clause within the body of a claim, rather than immediately following the preamble, it limits only the element described in that clause; other elements are not excluded in accordance with the claim as a whole.The transitional phrase "essentially consisting of" is used to define a composition, a procedure that includes materials, steps, features, components, or elements, in addition to those literally described, provided that these additional materials, steps, features, components, or elements do not materially affect the basic and novel feature(s), especially the mode of action for achieving the desired result of any of the processes described herein. The term "essentially consisting of" occupies an intermediate position between "comprising" and "consisting of." Furthermore, the use of "one" or "an" is employed to describe elements and components described herein. This is done solely for convenience and to give a general sense of the scope of the description. This description should be interpreted as inclusive of "one" or "at least one," and the singular also includes the plural, unless it is obvious otherwise. Unless otherwise defined, all technical and scientific terms used in this description have the same meaning as commonly understood by a person skilled in the art to which this description pertains. While methods and materials similar to or equivalent to those described herein may be used in the practice or testing of the modalities described herein, 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 quoted. In case of conflict, this description, including its definitions, shall prevail. Furthermore, the materials, methods, and examples are for illustrative purposes only and are not intended to be limiting. Illustrative synthetic processes are provided for preparing compositions (product mixtures) that include (Z)1,1,1,4,4,4-hexafluoro-2-butene (Z-1336mzz). The embodiments described herein include synthetic routes to 1,1,1,4,4,4-hexafluoro-2-butene (Z-1336mzz) from the readily available halogenated compounds CCl4, CF3CCl3, CH2=CCl2, and CF3CCl3=CH2. The processes described here can be carried out in a reactor suitable for the reaction conditions of temperature and pressure and made of a material resistant to the reactants and products used. The reactor can be constructed from materials resistant to the corrosive effects of hydrogen fluoride, such as stainless steel, Hastelloy®, Inconel®, Monel®, gold or gold-lined materials, or quartz. The reactions can be carried out in batch, continuous, semi-batch, or combinations thereof. Suitable reactors include batch reactor vessels and tubular reactors. Recovering means sufficiently isolating the desired product so that it is available for its intended use, either as a starting material for a subsequent reaction step or, in the case of recovering Z1,1,1,4,4,4-hexafluoro-2-butene, useful, for example, as or in a composition as a refrigerant or foam blowing agent or solvent or fire extinguisher or electronic gas or other use. The details of the recovery step will depend on the compatibility of the product mixture with the reaction conditions of the subsequent reaction step. For example, if the product is produced in a reaction medium that is different from or incompatible with a subsequent reaction step, then the recovery step may involve separating the desired product from the product mixture that includes the reaction medium. This separation can occur simultaneously with the contact step when the desired product is volatile under the reaction conditions. Volatilization of the desired product can constitute its isolation and, thus, its recovery. If the volatilized product includes unwanted components, the desired product can be separated, for example, by selective distillation. The steps to recover the desired product from the product mixture preferably comprise separating the desired product from the catalyst or other component(s) of the product mixture used to produce the desired product or products produced in the process. This description provides, among other things, processes for producing Z-1336mzz, and intermediates for producing Z-1336mzz. Such a process uses low-cost, readily available starting materials such as 1,1,1-trichloro-2,2,2-trifluoroethane and carbon tetrachloride. Production of 1,1,1,3,3-pentachloro-4,4,4-trifluorobutane (CC13CH2CHC1CF3, 333jfa) In one embodiment for producing 1,1,1,3,3-pentachloro-4,4,4-trifluorobutane (CF3CCI2CH2CCI3, 333jfa), 1,1,l-trichloro-2,2,2-trifluoroethane (CF3CCI3, 113a) is loaded into a reactor, heated and contacted with vinylidene chloride (CH2=CC12, VDC), in the presence of a catalyst comprising copper(II) chloride and a mononitrile, at a temperature and pressure sufficient to form 1,1,1,3,3-pentachloro-4,4,4-trifluorobutane, as shown in Reaction Scheme (1A). Cl Cu(ll) catalyst CF3CCI3 + Y -------------► cf3cci2ch2cci3cr H Reaction scheme 1A In an alternative embodiment for producing 1,1,1,3,3-pentachloro-4,4,4-trifluorobutane, carbon tetrachloride (CC14) is loaded into a reactor, heated and contacted with 2-chloro-3,3,3-trifluoropropene (CF3CC1=CH2, 1233xf), in the presence of a catalyst comprising copper(II) chloride and a mononitrile, at a temperature and pressure sufficient to form 1,1,1,3,3-pentachloro-4,4,4-trifluorobutane, as shown in Reaction Scheme (IB). iviA / a / zuzz / u 1 uo 1a CCI4+ Cl Catalyst Cu(ll) ____________CF3CCI2CH2C Reaction scheme IB In some embodiments, the above additions of a halogenated alkane to an olefin can be carried out at a temperature of approximately 50 °C to approximately 150 °C. In some embodiments, the temperature is from 50 to 130 °C. In some embodiments, the reaction is carried out as a batch reaction and the reaction time can be up to 2 hours, up to 5 hours, up to 10 hours, up to 15 hours, up to 18 hours, up to 20 hours, up to 22 hours, up to 24 hours, less than 36 hours, less than 32 hours, less than 28 hours, less than 26 hours, and combinations thereof. In some forms, the reaction can be carried out at a reactor pressure of 1 pounds per square inch gauge (psig) to 300 pounds per square inch gauge (psig) (approximately 7 to approximately 2000 kPa). The mononitrile can be selected from acetonitrile, propionitrile, or butyronitrile. In some embodiments, the mononitrile is propionitrile. The molar ratio of mononitrile to the Cu(II) catalyst is at least 10 and no more than 25. This ratio can be between 10 and 20, between 15 and 25, or between 15 and 20. The process for producing 333jfa may further comprise recovering 333jfa from the product mixture before using the recovered 333jfa as a starting material in a process for producing HCFC-336mfa, HCFC-336mfa, 1,1,1,4,4,4-hexafluoro-2-butyne, and HFO-Z-1336mzz, for example, as described herein. Processes for recovering 333jfa from the product mixture may include one or any combination of purification techniques, such as distillation, that are known in the art. Upon recovery of 333jfa from the product mixture, a product comprising at least 95%, 97%, or 99% of 333jfa is produced. Production of 2,2-dichloro-l,1,1,4,4,4-hexafluorobutane (CF3CCI2CH2CF3, 336mfa) In one embodiment, 1,1,1,3,3-pentachloro-4,4,4-trifluorobutane (333jfa) undergoes a fluorination reaction. In this embodiment, 1,1,1,3,3-pentachloro-4,4,4-trifluorobutane is contacted with hydrogen fluoride (HF) in the presence of a fluorination catalyst at a temperature and pressure sufficient to form a product comprising 2,2-dichloro-1,1,4,4,4-hexafluorobutane, as shown in Reaction Scheme (2). CF3CCI2CH2CCI3 + HF Fluoradon CataHzator CF3CCI2CH2CF3 Reaction scheme 2 The reaction with HF can be carried out in the gas phase or the liquid phase. A liquid medium can be added to the liquid-phase reaction. An example of a liquid medium is reagent 333jfa itself. The gas-phase or liquid-phase reaction includes a fluorination catalyst. The fluorination reaction can be carried out in a reaction zone comprising any reaction vessel of suitable size for the scale of the reaction. In some embodiments, the reaction zone comprises a reaction vessel made of corrosion-resistant materials. In some embodiments, these materials comprise alloys, such as nickel-based alloys like Hastelloy®, commercially available nickel-chromium alloys from Special Metals Corp. under the trademark Inconel® (hereinafter Inconel®), or commercially available nickel-copper alloys from Special Metals Corp. (New Hartford, New York) under the trademark Monel®, or vessels having fluoropolymer linings. In other embodiments, the reaction vessel can be made of other materials of construction, including stainless steels, particularly type U01 and austenitic stainless steels, and copper-clad steel. In a catalyzed gas-phase fluorination process, the fluorination catalyst can be selected from carbon; graphite; alumina; fluorinated alumina; aluminum fluoride; carbon-supported alumina; carbon-supported aluminum fluoride; carbon-supported fluorinated alumina; aluminum fluoride-supported magnesium fluoride; metals (including elemental metals, metal oxides, metal halides and / or other metal salts); metals supported on aluminum fluoride; metals supported on fluorinated alumina; metals supported on alumina; and metals supported on carbon; mixtures of metals. Suitable metals for use in fluorination catalysts (optionally supported on alumina, aluminum fluoride, fluorinated alumina, or carbon) include chromium, iron, cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium, platinum, manganese, rhenium, scandium, yttrium, lanthanum, titanium, zirconium, and hafnium, copper, silver, gold, zinc, and / or metals having an atomic number from 58 to 71 (i.e., the lanthanide metals). Preferably, when used on a support, the total metal content of the catalyst shall be approximately 0.1 to approximately 20 percent by weight based on the total weight of the catalyst; typically, approximately 0.1 to approximately 10 percent by weight based on the total weight of the catalyst. ud iy Fluorination catalysts useful for the gas-phase process include chromium-based catalysts, such as chromium oxyfluoride or chromium oxide. This catalyst may be unsupported or supported on a support such as activated carbon, graphite, fluorinated graphite, or fluorinated alumina. The chromium catalyst may be used alone or in the presence of a cocatalyst selected from a nickel, cobalt, manganese, or zinc salt. In some embodiments, a chromium catalyst is a large surface area chromium oxide, or chromium / nickel in alumina fluoride (Cr / Ni / AlF3), the production of which is reported in European patent no. EP 486,333. Chromium oxyfluoride catalysts can be prepared by processes known to those skilled in the art, such as, for example, treating CryOs (chromium oxide) concentration with HF, CCl3F or hydrofluorocarbons, as described in WO 2012 / 067864 Al. Preferably, chromium catalysts are activated prior to use, for example, as described in U.S. Patent No. 9,302,962. In a gas-phase fluorination process, the molar ratio of HF to 333jfa in some configurations can be from approximately 1 to approximately 35. In other configurations, the molar ratio of HF to 333jfa is from approximately 1 to approximately 25. HF can be added in an amount of 10 to 30 mol per mole of 333jfa. In some forms, the fluorination process is carried out at a high temperature, for example, in the range of 150 to 400 °C or 275 to 375 °C. In some forms, the temperature is in the range of 300 to 350 °C. In some embodiments, the fluorination process is carried out at a pressure in the range of 0 to 200 psi (0 to 1.4 MPa). In some embodiments, the reaction is carried out at substantially atmospheric pressure. In some modalities, the contact time for the fluoridation process can range from approximately 1 second to approximately 100 seconds. In some modalities, the contact time for the gas-phase fluoridation process can range from approximately 10 to approximately 100 seconds or from 10 seconds to 30 seconds. In other modalities, the contact time for the gas-phase fluoridation process can range from 50 to approximately 80 seconds. The gas-phase fluorination reaction may further comprise the recovery of 336mfa from the product mixture to reduce the other components of the product mixture. Processes for recovering 336mfa may include one or any combination of purification techniques, such as distillation, that are known in the art. Upon recovery of 336mfa from the product mixture, a product is obtained that comprises at least 98.5%, at least 97%, or at least 99.5% of 336mfa. In a catalyzed liquid-phase fluorination process, the fluorination catalyst can include a Lewis acid catalyst such as a metal halides. The halide can be selected from fluoride, chloride, or bromide. The metal halide can be a transition metal halide or another metal halide. Transition metal chlorides include halides of titanium, tantalum, niobium, tin, tungsten, and antimony. Other suitable metal halide catalysts include boron trifluoride. In some embodiments, the fluorination catalyst is selected from SbF5, and the product is selected from SbF5, SbCls, SbCl2, 3NO14, TaCls, TiCl4, NbCls, MoClg, WCle, antimony(V) chlorofluorides, and combinations thereof. In some embodiments, the metal halide is SbF5. In some embodiments, the metal halide is TaCl5. In some embodiments, the metal halide is antimony(V) chlorofluoride. In one embodiment, the catalyst includes tantalum pentachloride, antimony pentachloride, or antimony pentafluoride. In a liquid-phase fluorination process, hydrogen fluoride is present at a molar ratio of HF at 333jfa of between 7:1 and 15:1. In one embodiment, hydrogen fluoride is present at a molar ratio of HF at 333jfa of approximately 10:1. In some methods, the liquid-phase fluorination process is carried out at a temperature between 50 °C and 160 °C. In some methods, the temperature may be higher than 100 °C. In other methods, the temperature may be lower than 150 °C. In some embodiments, the liquid-phase fluorination reaction is carried out at a pressure in the range of 0 to 600 psi (0 to 4.1 MPa). In some embodiments, the reaction is carried out at substantially atmospheric pressure. In some modalities, the contact time of a liquid-phase fluorination reaction is from approximately 1 minute to approximately 24 hours, or from approximately 10 minutes to approximately 12 hours, or from approximately 1 hour to approximately 6 hours. The desired product, HCFC-336mfa, can be recovered from the reactor when the process is carried out in a liquid medium by purging unreacted chlorine, distilling unreacted 333jfa, and filtering out the catalyst. When carried out in the liquid phase, the catalyst can be filtered out if it is present at a concentration high enough to precipitate from the product mixture before, during, or after distillation. Alternatively, the catalyst can remain in the distillation material. In some formulations, the mixture of products from the fluorination reaction may undergo recovery and purification steps. Such steps may include washing with water, drying, and distillation. The product produced in a gas-phase or liquid-phase fluorination process may comprise CF3CCI2CH2CF3 (336mfa) and additional compounds selected from CF3CC12CH2CFC12, CHF2CH2CCI2CF3 and mixtures thereof. Production of 1,1,1,4,4,4-hexafluoro-2-butyne The present description further provides a process comprising contacting HCFC-336mfa with a base to produce a product mixture comprising 1,1,1,4,4,4-hexafluoro-2-butyne (CF3C=CCF3) in a dehydrochlorination reaction, as shown in Reaction Scheme (3). The base is preferably a basic aqueous medium. This reaction step is preferably carried out in the presence of a phase-transfer catalyst. Phase transfer catalyst CF3CCI2CH2CF3 + Base -------------k CF3-CeC-CF3 Reaction scheme 3 The basic aqueous medium comprises a solution of an alkali metal hydroxide or alkali metal halide salt or other base in water. The base may be selected from hydroxide, oxide, carbonate, or phosphate salts of alkali metals, alkaline earth metals, and mixtures thereof. In some embodiments, the base is selected from lithium hydroxide, sodium hydroxide, potassium hydroxide, calcium hydroxide, magnesium oxide, calcium oxide, sodium carbonate, potassium carbonate, sodium phosphate, potassium phosphate, and mixtures thereof. In some embodiments, the aqueous basic solution has a pH greater than 8. In some embodiments, the aqueous basic solution has a pH greater than 10. In some embodiments, the aqueous basic solution has a pH of 10–13. In some embodiments, the aqueous basic solution contains small amounts of organic liquids that may be miscible or immiscible in water. In some embodiments, the liquid in the aqueous basic solution is at least 90% water. In some embodiments, the water is tap water; in other embodiments, the water is deionized or distilled. This reaction step is preferably carried out in the presence of a phase-transfer catalyst. As used in this description, a phase-transfer catalyst is a substance that facilitates the transfer of ionic compounds between an organic phase and an aqueous phase. In this step, the organic phase comprises the reactant HCFC-336mfa, and the aqueous phase comprises the basic aqueous medium. The phase-transfer catalyst facilitates the reaction of these different and incompatible components. Although various phase-transfer catalysts may operate in different ways, their mechanism of action is not the determining factor in their usefulness in the processes described herein, provided that the phase-transfer catalyst facilitates the dehydrochlorination reaction. A suitable phase-transfer catalyst includes quaternary alkylammonium salts. In some embodiments, the catalyst includes tetrabutylammonium bromide or N-methyl-N,N,N-trioctylammonium chloride. In some embodiments, at least one alkyl group of the quaternary alkylammonium salt contains at least eight carbon atoms. An example of a quaternary alkylammonium salt in which three alkyl groups contain at least eight carbon atoms is N-methyl-N,N,N-trioctylammonium chloride, marketed under the trade name ALIQUAT® 336 by Alfa Aesar - Fisher Scientific. An example of a quaternary alkylammonium salt in which four alkyl groups contain at least eight carbon atoms is tetraoctylammonium chloride. The anions of such salts can be halides such as chloride or bromide, hydrogen sulfate, or any other commonly used anion. Specific quaternary alkylammonium salts include tetraoctylammonium chloride, tetraoctylammonium hydrogen sulfate, tetraoctylammonium bromide, methyltrioctylammonium chloride, methyltrioctylammonium bromide, tetradecylammonium chloride, tetradecylammonium bromide, and tetradodecylammonium chloride. According to one embodiment, a process for producing a mixture of products comprising CFaC^cCFa comprises contacting 336mfa with a base and a phase transfer catalyst under reaction conditions effective to achieve the conversion of 336mfa of at least 50% per hour. In other embodiments, the alkyl groups of the quaternary alkylammonium salt contain 4 to 10 carbon atoms, and a nonionic surfactant is present in the aqueous basic medium. According to such embodiments, the phase-transfer catalyst and reaction conditions are effective in achieving the conversion of HCFC-336mfa, preferably at at least 20% per hour. The anions of the quaternary alkylammonium salt, where the alkyl group contains 4 to 10 carbon atoms, can be halars, such as chloride or bromide, hydrogen sulfate, or any other commonly used anion. The quaternary alkylammonium salts mentioned above can be used in this embodiment provided their alkyl groups contain 4 to 10 carbon atoms. Specific additional salts include tetrabutylammonium chloride, tetrabutylammonium bromide, and tetrabutylammonium hydrogen sulfate. Preferred nonionic surfactants include ethoxylated nonylphenol or a C12-C15 ethoxylated linear aliphatic alcohol. Useful nonionic surfactants include Bio-soft® N25-9 and Makon® 10, which can be obtained from Stepan Company, Northfield, IL. In some embodiments, the quaternary alkylammonium salt is added in an amount of 0.5 mol% to 2 mol% of HCFC-336mfa. In other embodiments, the quaternary alkylammonium salt is added in an amount of 1 mol% to 2 mol% of HCFC-336mfa. Still in other embodiments, the quaternary alkylammonium salt is added in an amount of 1 mol% to 1.5 mol% of HCFC-336mfa. In some embodiments, the quaternary alkylammonium salt is added in an amount of 1 mol% to 1.5 mol% of HCFC-336mfa, and the weight of the added nonionic surfactant is 1 to 2 times the weight of the quaternary alkylammonium salt. These amounts apply to each of the aforementioned embodiments of the quaternary alkylammonium salt used. In some embodiments, the reaction mixture is heated to a temperature of 50 °C to 95 °C, preferably carried out at a temperature from approximately 60 to 90 °C, with the highest preference being 70 °C. In some modalities, the reaction is heated for approximately 1 hour to approximately 10 hours, approximately 2 hours to approximately 6 hours, approximately 4 hours to approximately 5 hours, and combinations of these. In some forms, the reaction takes place at a substantially atmospheric pressure. ud iy In some formulations, the base includes a strong base. In some formulations, the base includes aqueous sodium hydroxide or potassium hydroxide. In some embodiments, the dehydrochlorination reaction of 336mfa to 1,1,1,4,4,4-hexafluoro-2-butyne is carried out in the presence of an alkali metal halide salt. The alkali metal can be sodium or potassium. The halide can be chloride or bromide. A preferred alkali metal halide salt is sodium chloride. Without intending to be tied to any particular theory, it is believed that the alkali metal halide salt stabilizes the phase-transfer catalyst. Although the dehydrochlorination reaction itself produces alkali metal chloride, and in particular sodium chloride, if sodium hydroxide is used as a base, the addition of more sodium chloride provides the additional effect of increasing the yield of 1,1,1,4,4,4-hexafluoro-2-butyne. In some embodiments, the alkali metal halide is added at approximately 25 to approximately 100 equivalents per mole of phase transfer catalyst.In other embodiments, the alkali metal halide is added at approximately 30 to approximately 75 equivalents per mole of phase-transfer catalyst. In still other embodiments, the alkali metal halide is added at approximately 40 to approximately 60 equivalents per mole of phase-transfer catalyst. These amounts apply to each of the quaternary alkylammonium salts mentioned above. The product 1,1,1,4,4,4-hexafluoro-2-butyne (boiling point -25 °C) can be recovered from the product mixture by distillation, where the butyne is evaporated from the aqueous medium and can then be condensed. Production of Zl,1,1,4,4,4-hexafluoro-2-butene The present description further provides a hydrogenation process comprising contacting 1,1,1,4,4,4-hexafluoro-2-butyne with hydrogen at a temperature and pressure sufficient to produce a mixture of products comprising Z1,1,1,4,4,4-hexafluoro-2-butene (Z-1336mzz), as shown in Reaction Scheme (4). This process is preferably carried out in the presence of a hydrogenation catalyst, which is an alkyne-to-alkene catalyst. CFo Hydrogenation catalyst CF3-CeC-CF3+ H2 H Reaction scheme 4 In some embodiments, the hydrogenation catalyst is a palladium catalyst, such as a catalyst comprising palladium dispersed in aluminum oxide or titanium silicate, doped with silver and / or a lanthanide. The palladium loading in the aluminum oxide or titanium silicate is relatively low. In some embodiments, the palladium loading is approximately 100 ppm to approximately 5000 ppm. In other embodiments, the palladium loading is approximately 200 ppm to approximately 5000 ppm. In some embodiments, the palladium catalyst is doped with at least one of silver, cerium, or lanthanum. In some embodiments, the molar ratio of cerium or lanthanum to palladium is approximately 2:1 to approximately 3:1. In some embodiments, the molar ratio of silver to palladium is approximately 0.5:1. In some forms, the hydrogenation catalyst includes Lindlar (5% Pd on lead-intoxicated CaCO₃). The lead compound can be lead acetate, lead oxide, or any other suitable lead compound. The Lindlar catalyst can be deactivated or conditioned with quinoline. The amount of palladium on the support is typically about 5 wt%, but it can be any catalytically effective amount. In some embodiments, the amount of palladium on the support in the Lindlar catalyst is greater than 5 wt%. Even in some other embodiments, the amount of palladium on the support can range from about 5 wt% to about 1 wt%. In some embodiments, the amount of catalyst used is approximately 0.5 wt% to approximately 4 wt% of the amount of 1,1,1,4,4,4-hexafluoro-2-butyne. In other embodiments, the amount of catalyst used is approximately 1 wt% to approximately 3 wt% of the amount of butyne. Still in other embodiments, the amount of catalyst used is approximately 1 wt% to approximately 2 wt% of the amount of butyne. In some embodiments, the amount of catalyst used is approximately 0.5 wt% to approximately 4 wt% of the amount of 1,1,1,4,4,4-hexafluoro-2-butyne. In other embodiments, the amount of catalyst used is approximately 1 wt% to approximately 3 wt% of the amount of butyne. Still in other embodiments, the amount of catalyst used is approximately 1 wt% to approximately 2 wt% of the amount of butyne. In some embodiments, the reaction step is carried out in the presence of a solvent. In one such embodiment, the solvent is an alcohol. Typical alcoholic solvents include ethanol, i-propanol, and n-propanol. In other embodiments, the solvent is a fluorocarbon or hydrofluorocarbon. Typical fluorocarbons or hydrofluorocarbons include 1,1,1,2,2,3,4,5,5,5-decafluoropentane and 1,1,2,2,3,3,4-heptafluorocyclopentane. In some embodiments, the reaction of 1,1,1,4,4,4-hexafluoro-2-butyne with hydrogen is preferably carried out by adding hydrogen in portions, with increases in vessel pressure of no more than approximately 100 psi (0.69 MPa) with each addition. In other embodiments, the addition of hydrogen is controlled so that the vessel pressure increases by no more than approximately 50 psi (0.35 MPa) with each addition. In some embodiments, after sufficient hydrogen has been consumed in the hydrogenation reaction to convert at least 50% of the butyne to Z-1336mzz, hydrogen may be added in larger increments during the remainder of the reaction. In other embodiments, after sufficient hydrogen has been consumed in the hydrogenation reaction to convert at least 60% of the butyne to the desired butene, hydrogen may be added in larger increments during the remainder of the reaction.Even in other embodiments, after sufficient hydrogen has been consumed in the hydrogenation reaction to convert at least 70% of the butyne to the desired butene, hydrogen can be added in larger increments during the remainder of the reaction. In some embodiments, the largest increments of hydrogen addition can be 300 psi (2.07 MPa). In other embodiments, the largest increments of hydrogen addition can be 400 psi (2.76 MPa). In some embodiments, the molar ratio is approximately 1 mole of hydrogen to approximately 1 mole of 1,1,1,4,4,4-hexafluoro-2-butyne. In other embodiments, the molar ratio is approximately 0.9 mol to approximately 1.3 mol of hydrogen to butyne. Still in other embodiments, the amount of hydrogen added is approximately 0.95 mol of hydrogen to approximately 1.1 mol of butyne. Still in other embodiments, the amount of hydrogen added is approximately 0.95 mol of hydrogen to approximately 1.03 mol of butyne. In some methods, hydrogenation is carried out at room temperature (15 °C to 25 °C). In other methods, hydrogenation is carried out above room temperature. In still other methods, hydrogenation is carried out below room temperature. In yet other methods, hydrogenation is carried out at a temperature below approximately 0 °C. In some embodiments, a reaction vessel containing hexafluoro-2-butyne and a catalyst is cooled to approximately -78 °C under reduced pressure. The reactor temperature may then be allowed to warm to room temperature. Hydrogen gas may then be slowly added to the reaction vessel. In some embodiments, the rate of hydrogen gas addition is regulated to result in a pressure change within the reaction vessel of less than 70 psi, less than 60 psi, and / or less than 50 psi. Hydrogen addition may continue until a slight excess of hydrogen is provided to the reaction vessel. In one embodiment of a continuous process, a mixture of 1,1,1,4,4,4-hexafluoro-2-butyne and hydrogen is passed through a reaction zone containing the catalyst. A reaction vessel, e.g., a metal tube, filled with the catalyst, can be used to form the reaction zone. In some embodiments, the molar ratio of hydrogen to butyne is approximately 1:1. In other embodiments of a continuous process, the molar ratio of hydrogen to butyne is less than 1:1. Still in other embodiments, the molar ratio of hydrogen to butyne is approximately 0.67:1.0. In some forms of a continuous process, the reaction zone is maintained at room temperature. In other forms of a continuous process, the reaction zone is maintained at a temperature of 30 °C. In still other forms of a continuous process, the reaction zone is maintained at a temperature of approximately 40 °C. In some embodiments of a continuous process, the flow rate of 1,1,1,4,4,4-hexafluoro-2-butyne and hydrogen is maintained to provide a residence time in the reaction zone of approximately 30 seconds. In other embodiments of a continuous process, the flow rate of butyne and hydrogen is maintained to provide a residence time in the reaction zone of approximately 15 seconds. Still in other embodiments of a continuous process, the flow rate of butyne and hydrogen is maintained to provide a residence time in the reaction zone of approximately 7 seconds. The contact time in the reaction zone is understood to decrease as the flow rate of 1,1,1,4,4,4-hexafluoro-2-butyne and hydrogen in the reaction zone increases. As the flow rate increases, the amount of butyne hydrogenated per unit time also increases. Since hydrogenation is exothermic, depending on the length and diameter of the reaction zone and its heat dissipation capacity, at higher flow rates it may be desirable to provide an external cooling source to the reaction zone to maintain the desired temperature. In some embodiments, after the completion of a continuous or batch hydrogenation process, Z-1336mzz can be recovered by any conventional process, including, for example, fractional distillation. In other embodiments, after the completion of a continuous or batch hydrogenation process, Z-1336mzz is of sufficient purity to not require additional purification steps. The reaction product 1,1,1,4,4,4-hexafluoro-2-butene can be recovered in high yield and high purity by distillation of the reaction mixture. In some embodiments, the reaction yield of Reaction Scheme 4 is greater than 95 percent, greater than 96 percent, greater than 97 percent, and / or greater than 98 percent. EXAMPLES The concepts described herein will be described in more or less detail in the following examples, which do not limit the scope of the present description in the claims. Iron powder, vinylidene chloride, Aliquat® 336, and sodium hydroxide are available from Sigma Aldrich, St. Louis, MO. 113a, 1, 1, l-trichloro-2,2,2-trifluoroethane (CF3CCI3) , 2chloro-3,3,3-trifluoropropene (CF3CC1=CH2) , hydrogen fluoride and SbCls are acquired from Synquest Labs, Inc. Example 1 (Comparison). Stage 1. 113a VDC insertion to produce CF3CCI2CH2CCI3 Vinylidene chloride (26 g, 0.265 mol) was added to the mixture of 113a (100 g, 0.53 mol), powdered Fe (0.62 g, 0.011 mol), and triphenylphosphine (1.41 g, 0.0054 mol) in a 240 mL Hastelloy reactor. The reactor was heated to 150 °C for 5 hours. The mixture was transferred to a vessel and analyzed by GC: GC yield at 24% (30% conversion and 80% product selectivity). Example 2. Stage 1. 113a VDC insertion to produce CF3CCI2CH2CCI3 The mixture of vinylidene chloride (2.4 g, 0.025 mol) and 113a (23 g, 0.125 mol) was heated to 100 °C for 24 hours in the presence of anhydrous copper(II) chloride (0.34 g, 0.0025 mol) along with 3 mL of propionitrile in a 100 mL stainless steel autoclave. The mixture was transferred to a container and analyzed by GC: 32% GC yield (conversion 40%, product selectivity 80%). Example 3 (Comparison). Step 1. Insertion of 2-chloro-3,3,3-trifluoropropene from CCl4 to produce CF3CCl2CH2CCl3 The mixture of 2-chloro-3,3,3-trifluoropropene (32.6 g, 0.25 mol) and CC14 (77 g, 0.5 mol) was heated to 130 °C for 5 hours in the presence of powdered Fe (0.62 g, 0.011 mol) and triphenylphosphine (1.40 g, 0.005 mol) in a 300 mL Hastelloy reactor. The mixture was transferred to a container and analyzed by GC: conversion 55% and selectivity to the product is 86%. Example 4. Step 1. Insertion of 2-chloro-3,3,3-trifluoropropene from CC14 to produce CF3CCI2CH2CCI3 The mixture of 2-chloro-3,3,3-trifluoropropene (3.3 g, 0.025 mol) and CC14 (7.7 g, 0.05 mol) was heated to 100 °C for 22 hours in the presence of anhydrous copper(II) chloride (0.34 g, 0.0025 mol) in 3 mL of propionitrile in a 100 mL stainless steel autoclave. The mixture was purified by fractionation, and the distillate yield to the product was 62%. The product CF3CC12CH2CC13 was recovered from the product mixtures of Examples 1-4 and has the following properties: boiling point 56-58 °C (13 mm Hg); 1H NMR (CDC13): δ ppm 3.72 (CH2, s); 19F NMR (CDC13): δ ppm 80.47 (CF3, s); MS (m / z): 248.75 (M-Cl), 246.75 (M-Cl-2H). Example 5. Step 2: Liquid-phase fluorination of CF3CC12CH2CC13 to produce CF3CC12CH2CF3 (336 mfa) using an antimony catalyst A mixture of 1,1,1,3,3-pentachloro-4,4,4-trifluorobutane (2 g, 0.007 mol), anhydrous HF (4.2 g, 0.021 mol), and antimony pentachloride (0.5 g, 0.002 mol) was stirred in a PTFE-lined container at 110 °C. The reaction mixture was poured onto crushed ice. The organic layer was washed with water (twice) and dried with MgSO4. Distillation at 65–68 °C yielded 1.9 g of product (81% yield). The product was recovered with the following properties: 1 H NMR (CDC13): δ ppm 3.15 (q, JHF = 9.4 Hz, CH2); 19F NMR (CDC13) δ ppm: -62.7 (t, JFH = 9.4 Hz, 2F, CH2CF3), -83.2 (s, 3F, cF3). Example 6. Step 2: Liquid phase fluorination of CF3CC12CH2CC13 to produce CF3CC12CH2CF3 (336mfa) using a tantalum catalyst A mixture of 1,1,1,3,3-pentachloro-4,4,4-trifluorobutane (2 g, 0.007 mol), anhydrous HF (4.2 g, 0.021 mol), and tantalum pentachloride (0.6 g, 0.002 mol) is stirred in a PTFE-lined container at 130 °C. The reaction mixture is poured onto crushed ice. The organic layer is washed with water (twice) and dried with MgSO4. Distillation at 65–68 °C yields 2.1 g of product (88% yield). Example 7. Step 2: Gas phase fluorination of CF3CC12CH2CC13 to produce CF3CC12CH2CF3 (336mfa) An Inconel® tube (0.5-inch OD, 10-inch length, 0.034-inch wall thickness) was filled with 6 mL of Newport chromium catalyst. The reactor was heated to the desired temperature. CF3CC12CH2CC13 was fed through an ISCO pump (4.27 mL / h) and a controlled vaporizer at 170 °C. The HF / CF3CC12CH2CC13 molar ratio was 10, and the contact time was 10 seconds. The reaction was carried out at 0 psig. The reactor effluent was analyzed online using an Agilent® 6890 GC / 5973 MS, showing 95% conversion of the starting material, 70% selectivity at 336 mfa, and 30% selectivity at 1326 mxz (CF3CC1=CHCF3). Example 8. Step 3. Conversion of the quaternary ammonium salt of CF3CC12CH2CF3 to hexafluoro-2-butyne with Aliquat ® 336 Aqueous NaOH solution (22 mL, 0.22 mol) was added to HCFC-CF3CC12CH2CF3 (23.5 g, 0.1 mol) and water (5.6 mL) in the presence of Aliquat® 336 quaternary ammonium salt (0.53 g, 0.001325 mol) at room temperature. After the addition, the reaction temperature was raised to 70 °C, and gas chromatography was used to monitor the reaction. The reaction was complete after 2 hours, and hexaffluorobutylene was collected in a dry ice trap in a yield greater than 90%. Example 9. Step 3. Conversion of CF3CC12CH2CF3 to hexafluoro2-butyne using tetrabutylammonium bromide and surfactant Aqueous solution of NaOH (22 ml, 0.22 mol) is added to 336mfa (23.5 g, 0.1 mol) and water (5.6 ml) were added in the presence of tetrabutylammonium bromide (0.45 g, 0.001325 mol) and Makon® 10 surfactant (0.7 g) at room temperature. After the addition, the reaction temperature was raised to 70 °C and gas chromatography was used to monitor the reaction. The reaction was complete after 4.5 hours and the hexafluorobutyne was collected in a dry ice trap in a yield greater than 90%. Example 10. Step 4. Conversion of 1,1,1,4,4,4hexafluorobutyne to (Z)-1,1,1,4,4,4-hexafluoro-2-butene Five grams of Lindlar catalyst (5% Pd on lead-intoxicated CaCO3) were loaded into a 1.3 L agitator pump. Four hundred eighty-eight grams (2.96 mol) of hexafluoro-2-butyne were placed in the agitator. The reactor was cooled to -78 °C and evacuated. After warming the pump to room temperature, hydrogen was added slowly in increments not exceeding ΔP = 50 psi (0.35 MPa). A total of 3 mol of hydrogen was added to the reactor. Gas chromatographic analysis of the crude product indicated that the mixture consisted of CF3C=CCF3 (0.236%), the trans-isomer (E)CF3CH=CHCF3 (boiling point 33.3 °C, MS: 164 [MI], 145 [M-19], 95 [CF3CH=CH], 69 [CF3]; 1H NMR: 6.12 ppm (multiplet), 19F NMR: -60.9 ppm (triplet J = 0.86 Hz). The selectivity of this reaction for the formation of the Z isomer was 96.98%. The Z isomer was recovered by distillation. Please note that not all of the activities described above in the overview or examples are required, that part of a specific activity may not be necessary, and that one or more additional activities may be performed in addition to those described. Furthermore, the order in which the activities are listed is not necessarily the order in which they are performed. The benefits, other advantages, and solutions to problems have been described above with respect to specific modalities. However, the benefits, advantages, solutions to problems, and any feature that may produce or enhance a benefit, advantage, or solution shall not be construed as a critical, necessary, or essential feature under any of the claims. It is understood that, for ease of understanding, certain characteristics described herein in the context of individual modalities may also be provided combined into a single modality. Conversely, several characteristics that, for the sake of brevity, are described in the context of a single modality may also be provided separately or in any subcombination. Furthermore, references to the values ​​indicated in the intervals include every value within that interval. Although the processes described here are presented with reference to a preferred modality, those skilled in the technique will understand that various changes can be made and that equivalent elements can be substituted without exceeding the scope of the description. Furthermore, many modifications can be made to adapt a particular situation or material to the teachings of the description without departing from its essential scope. It is hereby stated that, as of this date, the best method known to the applicant for putting the aforementioned invention into practice is the one that is clear from the present description of the invention.

Claims

1. A process for producing a mixture of products comprising 1,1,1,3,3-pentachloro-4,4,4-trifluorobutane (CCl3CH2CHCICF3, 333jfa), characterized in that it comprises contacting a halogenated alkane with an olefin in the presence of a mononitrile and a catalyst comprising copper(II) chloride, wherein the halogenated alkane is selected from 1,1,1-trichloro-2,2,2-trifluoroethane (CF3CCI3, 113a) and carbon tetrachloride (CCl14), provided that when the halogenated alkane is 1,1,1-trichloro-2,2,2-trifluoroethane, the olefin is vinylidene chloride (CH2=CCl12, VDC) and when the halogenated alkane is carbon tetrachloride, the olefin is 2-chloro3,3,3-trifluoropropene (CF3CC1=CH2, 1233xf).

2. The process according to claim 1, characterized in that the mononitrile is selected from acetonitrile, propionitrile, butyronitrile.

3. The process according to claim 2, characterized in that the mononitrile is propionitrile.

4. The process according to any of claims 1-3, characterized in that the halogenated alkane is 1,1,l-trichloro-2,2,2-trifluoroethane and the olefin is vinylidene chloride.

5. The process according to any of claims 1-3, characterized in that the halogenated alkane is carbon tetrachloride and the olefin is 2-chloro3,3,3-trifluoropropene.

6. The process according to any of claims 1-5, characterized in that the molar ratio of mononitrile to the catalyst is at least 10 and less than 25.

7. The process according to claim 4, characterized in that the molar ratio of mononitrile to the catalyst is between 10 and 20.

8. The process according to claim 4, characterized in that the molar ratio of mononitrile to the catalyst is between 15 and 20.

9. The process according to claim 1, characterized in that it further comprises contacting 1,1,1,3,3-pentachloro-4,4,4-trifluorobutane with HE in the gas or liquid phase, with hydrogen fluoride in the presence of a fluorination catalyst, forming a product comprising 2,2-dichloro-1,1,4,4,4-hexafluorobutane.

10. The process according to claim 9, characterized in that the process of contacting 1,1,1,3,3-pentachloro-4,4,4-trifluorobutane with HF is carried out in the gas phase.

11. The process according to claim 9, characterized in that the process of contacting 1,1,1,3,3-pentachloro-4,4,4-trifluorobutane with HF is carried out in the liquid phase.

12. The process according to claim 9, characterized in that it further comprises contacting 2,2-dichloro-1,1,1,4,4,4-hexafluorobutane with a base to produce a mixture of products comprising 1,1,1,4,4,4-hexafluoro-2-butyne (CFaC^CCFs); 13. The process according to claim 12, characterized in that it is carried out in the presence of a phase transfer catalyst.

14. The process according to claim 13, characterized in that the phase transfer catalyst includes a quaternary ammonium salt.

15. The method according to claim 14, characterized in that the quaternary ammonium salt includes tetrabutylammonium bromide or N-methyl-N,N,Ntrioctylammonium chloride.

16. The method according to claim 12, characterized in that it further comprises contacting 1,1,1,4,4,4-hexafluoro-2-butyne with hydrogen at a temperature and pressure sufficient to produce a mixture of products comprising 1,1,1,4,4,4,4-hexafluoro-2-butene.

17. The method according to claim 9, characterized in that the hydrogenation catalyst is a palladium catalyst.

18. The method according to claim 17, characterized in that the palladium catalyst is a Lindlar catalyst.

19. The method according to claim 17, characterized in that the palladium catalyst comprises palladium dispersed on aluminum oxide or titanium silicate, doped with silver and / or a lanthanide.