Process for preparing (Z)-1,1,1,4,4,4-hexafluoro-2-butene and intermediates

Abstract

The present invention describes a method for preparing (Z)-1,1,1,4,4,4-hexafluoro-2-butene (Z-1336mzz). The method utilizes readily available halogenated raw materials, including 1,1,1-trichloro-2,2,2-trifluoroethane (CFC-113a) and carbon tetrachloride.

Description

Technical Field

[0001] The present disclosure relates to methods for preparing (Z)-1,1,1,4,4,4-hexafluoro-2-butene (Z-1336mzz) and intermediates useful for such preparation. Specifically, the present disclosure relates to a method for preparing (Z)-1,1,1,4,4,4-hexafluoro-2-butene (Z-1336mzz) from readily available halogenated alkanes. Background Art

[0002] The fluorocarbon industry has been working for decades to find replacement refrigerants for the ozone-depleting chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) that are being phased out by the Montreal Protocol. The solution for many applications has been the commercialization of hydrofluorocarbon (HFC) compounds used as refrigerants, solvents, fire extinguishers, foam blowing agents, and propellants. These new compounds, which are currently the most widely used, such as HFC refrigerants, HFC-134a and HFC-125, have zero ozone depletion potential and are therefore not affected by the current Montreal Protocol phase-out regulations.

[0003] In addition to the problem of ozone depletion, global warming is another environmental concern in many of these applications. Therefore, there is a need for compositions that meet both low ozone depletion standards and low global warming potential (GWP). It is believed that certain hydrofluoroolefin compositions meet these two goals. Therefore, there is also a need to provide economical methods for making these compositions.

[0004] (Z)-1,1,1,4,4,4-hexafluoro-2-butene (Z-1336mzz) is a hydrofluoroolefin useful in refrigerants, heat transfer compositions, thermodynamic cycle (e.g., heating or cooling cycle) working fluids, aerosol propellants, blowing agents (foam blowing agents), solvents, cleaning agents, carrier fluids, displacement desiccants, polishing abrasives, polymerization media, blowing agents for polyolefins and polyurethanes, gaseous dielectrics, power cycle working fluids, fire extinguishing agents, and fire suppressants in liquid or gaseous form. The GWP of cis-HFO-1336mzz is estimated to be <10 for a 100 year time horizon based on an atmospheric lifetime.

[0005] There is a need in the art for methods that can efficiently and economically prepare (Z)-1,1,1,4,4,4-hexafluoro-2-butene (Z-1336mzz). Summary of the invention

[0006] The present disclosure provides a method for preparing hydrofluoroolefin Z-1,1,1,4,4,4-hexafluoro-2-butene (Z-CF3CH=CHCF3, Z-1336mzz) and intermediates useful for its preparation. The method described herein provides a cost-effective way to synthesize Z-1336mzz starting from CF3CCl3 and CH2=CCl2 or from CCl4 and CF3CI=CH2.

[0007] In one embodiment, a process for preparing a product mixture comprising 1,1,1,3,3-pentachloro-4,4,4-trifluorobutane (CCl3CH2CHClCF3, 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 (CF3CCl3, 113a) and carbon tetrachloride (CCl4), with the proviso that when the halogenated alkane is 1,1,1-trichloro-2,2,2-trifluoroethane, the olefin is vinylidene chloride (CH2=CCl2, VDC), and when the halogenated alkane is carbon tetrachloride, the olefin is 2-chloro-3,3,3-trifluoropropene (CF3CCl=CH2, 1233xf).

[0008] In one embodiment, the method includes contacting 333jfa prepared as described above with hydrogen fluoride (HF) in the gas phase or liquid phase in the presence of a fluorination catalyst under certain conditions to produce a product mixture comprising 2,2-dichloro-1,1,1,4,4,4-hexafluorobutane (CF3CCl2CH2CF3, 336mfa).

[0009] In one embodiment, the process comprises contacting 336mfa prepared as described above with a base and optionally a phase transfer catalyst to produce a product mixture comprising 1,1,1,4,4,4-hexafluorobutyne.

[0010] In one embodiment, 1,1,1,4,4,4-hexafluoro-2-butyne is reacted with hydrogen and a hydrogenation catalyst to produce a product mixture comprising Z-1,1,1,4,4,4-hexafluoro-2-butene (Z-1336mzz).

[0011] The present disclosure provides a method for preparing Z-1,1,1,4,4,4-hexafluoro-2-butene, the method comprising: (a) contacting a halogenated alkane with an olefin in the presence of a mononitrile and a catalyst comprising copper (II) chloride to prepare a product mixture comprising 1,1,1,3,3-pentachloro-4,4,4-trifluorobutane, 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; (b) in the presence of a fluorinated catalyst; (c) contacting 2,2-dichloro-1,1,1,4,4,4-hexafluorobutane with a base and a phase transfer catalyst to prepare a product mixture containing 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 prepare a product mixture containing Z-1,1,1,4,4,4-hexafluoro-2-butene.

[0012] In any of the foregoing methods, the desired product may be recovered from a product mixture comprising such desired product.

[0013] The foregoing general description and the following detailed description are exemplary and explanatory only and do not limit the present disclosure as defined in the appended claims. In conjunction with the present disclosure, other features and advantages of the method disclosed herein will be apparent from the following more detailed description of the preferred embodiments. DETAILED DESCRIPTION

[0014] As used herein, the terms "comprises," "including," "having," or any other variations thereof are intended to encompass non-exclusive inclusions. For example, a process, method, article, or device that includes a list of elements need not be limited to only those elements, but may include other elements that are not explicitly listed or that are inherent to such process, method, article, or device. In addition, unless expressly indicated to the contrary, "or" refers to an inclusive or and not an exclusive or. For example, a condition A or B satisfies one of the following conditions: A is true (or exists) and B is false (or does not exist), A is false (or does not exist) and B is true (or exists), and both A and B are true (or exist).

[0015] The transitional phrase "consisting of" excludes any unspecified elements, steps, or ingredients. If in a claim, protection for materials other than those described would be excluded, except for impurities normally associated therewith. When the phrase "consisting of" appears in a clause in the body of a claim, rather than immediately following the preamble, it limits only the elements described in that clause; other elements are not excluded from the claim as a whole. The transitional phrase "consisting essentially of" is used to define a composition, method, or composition that includes materials, steps, features, components, or elements in addition to those disclosed in the literature, provided that these additionally included materials, steps, features, components, or elements do not significantly affect the basic and novel characteristics, especially the mode of action of achieving the desired results of any of the methods disclosed herein. The term "consisting essentially of" occupies an intermediate position between "comprising" and "consisting of."

[0016] In addition, the use of "a" or "an" is used to describe elements and components described herein. This is for convenience only and to give a general sense of the scope of the present disclosure. The description should be understood to include one or at least one, and the singular also includes the plural, unless it is obvious that there is another meaning.

[0017] Unless otherwise defined, all technical and scientific terms used herein have the same meanings as those generally understood by those of ordinary skill in the art to which the present disclosure belongs. Although methods and materials similar to or equivalent to the methods and materials described herein can be used in the practice or testing of the embodiments of the present disclosure, suitable methods and materials are described below. Unless citing a specific paragraph, all publications, patent applications, patents and other references mentioned herein are incorporated herein by reference in their entirety. If a conflict occurs, this specification and the definitions included therein shall prevail. In addition, materials, methods and examples are exemplary only and are not intended to be limiting.

[0018] Provided is an exemplary synthetic method for preparing a composition (product mixture) comprising (Z)-1,1,1,4,4,4-hexafluoro-2-butene (Z-1336mzz). Embodiments of the present disclosure include a route to synthesize 1,1,1,4,4,4-hexafluoro-2-butene (Z-1336mzz) starting from readily available halogenated compounds CCl4, CF3CCl3, CH2=CCl2, CF3CCI=CH2.

[0019] The process disclosed herein can be carried out in a reactor suitable for the reaction conditions of temperature and pressure and made of materials resistant to the reactants and products employed. The reactor can be constructed of materials resistant to the corrosive effects of hydrogen fluoride, such as stainless steel, Gold or gold lined material or quartz. The reaction can be carried out batchwise, continuously, semi-continuously or in a combination thereof. Suitable reactors include batch reactor vessels and tubular reactors.

[0020] By "recovery" is meant sufficient isolation of the desired product to render it useful for its intended use, or as a starting material for a subsequent reaction step, or in the case of recovery of Z-1,1,1,4,4,4-hexafluoro-2-butene, for use as or in a composition for use as, for example, a refrigerant or foam expansion agent or solvent or fire extinguishing agent or electronic gas or for other uses.

[0021] 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 prepared in a reaction medium that is different from or incompatible with the subsequent reaction step, the recovery step may include separating the desired product from the product mixture comprising the reaction medium. When the desired product is volatile under the reaction conditions, the separation may occur simultaneously with the contacting step. The volatilization of the desired product may constitute the separation, thereby constituting the recovery of the desired product. If the volatilized product contains undesirable components, the desired product may be separated by, for example, selective distillation.

[0022] The step for recovering the desired product from the product mixture preferably comprises separating the desired product from the catalyst or other components of the product mixture produced in the process used to prepare the desired product.

[0023] The present disclosure provides, inter alia, methods for preparing Z-1336mzz and intermediates for preparing Z-1336mzz. Such methods use low-cost, readily available starting materials, such as 1,1,1-trichloro-2,2,2-trifluoroethane and carbon tetrachloride.

[0024] Preparation of 1,1,1,3,3-pentachloro-4,4,4-trifluorobutane (CCl3CH2CHClCF3, 333jfa)

[0025] In one embodiment, to prepare 1,1,1,3,3-pentachloro-4,4,4-trifluorobutane (CF3CCl2CH2CCl3, 333jfa), 1,1,1-trichloro-2,2,2-trifluoroethane (CF3CCl3, 113a) is charged into a reactor, heated, and contacted with vinylidene chloride (CH2=CCl2, VDC) in the presence of a catalyst including 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 Scheme (1A).

[0026]

[0027] In an alternative embodiment, to prepare 1,1,1,3,3-pentachloro-4,4,4-trifluorobutane, carbon tetrachloride (CCl4) is charged into a reactor, heated, and contacted with 2-chloro-3,3,3-trifluoropropene (CF3CCl=CH2, 1233xf) in the presence of a catalyst including 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 Scheme (1B).

[0028]

[0029] In some embodiments, the above addition of the halogenated alkane to the olefin may be carried out at a temperature of about 50° C. to about 150° C. In some embodiments, the temperature is 50° C. to 130° C. In some embodiments, the reaction is carried out as a batch reaction, and the reaction time may 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.

[0030] In some embodiments, the reaction may be conducted at a reactor pressure of 1 psig to 300 psig (about 7 kPa to about 2000 kPa).

[0031] The mononitrile can be selected from acetonitrile, propionitrile, butyronitrile. In some embodiments, the mononitrile is propionitrile. The molar ratio of the mononitrile to the Cu (II) catalyst is at least 10 and no more than 25. The ratio can be between 10 and 20 or between 15 and 25 or between 15 and 20.

[0032] The method for preparing 333jfa may also include recovering 333jfa from the product mixture, and then using the recovered 333jfa as a raw material in a method for preparing, for example, HCFC-336mfa, 1,1,1,4,4,4-hexafluoro-2-butyne and HFO-Z-1336mzz as described herein. The method for recovering 333jfa from the product mixture may include one or any combination of purification techniques known in the art (such as distillation). By "recovering" 333jfa from the product mixture, a product containing at least 95%, at least 97%, or at least 99% 333jfa is prepared.

[0033] Preparation of 2,2-dichloro-1,1,1,4,4,4-hexafluorobutane (CF3CCl2CH2CF3, 336mfa)

[0034] In one embodiment, 1,1,1,3,3-pentachloro-4,4,4-trifluorobutane (333jfa) is fluorinated. 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 2,2-dichloro-1,1,1,4,4,4-hexafluorobutane, as shown in Scheme (2).

[0035]

[0036] 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 the 333jfa reactant itself. The gas phase or liquid phase reaction includes a fluorination catalyst.

[0037] The fluorination reaction can be carried out in a reaction zone comprising any reaction vessel having a size suitable for the scale of the reaction. In some embodiments, the reaction zone comprises a reaction vessel constructed of corrosion resistant materials. In some embodiments, these materials include alloys, such as nickel-based alloys (such as ), available from Special Metals Corp. under the trademark (hereinafter referred to as ) or available from Special Metals Corp. (New Hartford, New York) under the trademark Commercially available nickel copper alloys, or containers with fluoropolymer linings. In other embodiments, the reaction vessel may be made of other materials of construction, including stainless steel (particularly austenitic stainless steel) and copper clad steel.

[0038] In the catalytic 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 on magnesium fluoride; metals (including elemental metals, metal oxides, metal halides and / or other metal salts); aluminum fluoride supported metals; fluorinated alumina supported metals; alumina supported metals; and carbon-supported metals; mixtures of metals.

[0039] Metals suitable for use in the vapor phase fluorination catalyst (optionally supported on alumina, aluminum fluoride, fluorided 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 atomic numbers from 58 to 71 (i.e., lanthanide metals). Preferably, when used on a support, the total metal content of the catalyst will be from about 0.1% to about 20% by weight, based on the total weight of the catalyst; typically from about 0.1% to about 10% by weight, based on the total weight of the catalyst.

[0040] Fluorination catalysts that can be used in gas phase processes include chromium-based catalysts such as chromium oxyfluoride or chromium oxide, which can be unsupported or supported on a support such as activated carbon, graphite, fluorinated graphite or fluorinated aluminum oxide. The chromium catalyst can be used alone or in the presence of a promoter selected from nickel, cobalt, manganese or zinc salts. In some embodiments, the chromium catalyst is high surface area chromium oxide or aluminum fluoride chromium / nickel (Cr / Ni / AlF3), the preparation of which is reported in European Patent EP486,333.

[0041] The chromium oxyfluoride catalyst can be prepared by methods known to those skilled in the art, such as, for example, by treating Cr2O3 (chromium oxide) with HF, CCl3F or hydrofluorocarbons, as disclosed in WO 2012 / 067864A1.

[0042] The chromium catalyst is preferably activated prior to use, for example, as disclosed in US Pat. No. 9,302,962.

[0043] In the vapor phase fluorination process, the molar ratio of HF to 333jfa may be, in some embodiments, from about 1 to about 35. In other embodiments, the molar ratio of HF to 333jfa is from about 1 to about 25. HF may be added in an amount of 10 to 30 moles per mole of 333jfa.

[0044] In some embodiments, the vapor phase fluorination process is conducted at elevated temperatures, for example, at a temperature in the range of 150° C. to 400° C. or 275° C. to 375° C. In some embodiments, the temperature is in the range of 300° C. to 350° C.

[0045] In some embodiments, the vapor phase fluorination process is conducted at a pressure in the range of 0 psi to 200 psi (0 MPa to 1.4 MPa). In some embodiments, the reaction is conducted at substantially atmospheric pressure.

[0046] In some embodiments, the contact time of the gas phase fluorination process may be from about 1 second to about 100 seconds. In some embodiments, the contact time of the gas phase fluorination process may be from about 10 seconds to about 100 seconds or from 10 seconds to 30 seconds. In other embodiments, the contact time of the gas phase fluorination process may be from 50 seconds to about 80 seconds.

[0047] The gas phase fluorination reaction may also include recovering 336mfa from the product mixture to reduce other components in the product mixture. The method for recovering 336mfa may include one or any combination of purification techniques known in the art, such as distillation. By "recovering" 336mfa from the product mixture, a product containing at least 98.5%, at least 99%, or at least 99.5% 336mfa is prepared.

[0048] In the catalytic liquid phase fluorination method, the fluorination catalyst may include a Lewis acid catalyst, such as a metal halide. The halide may be selected from fluoride, chloride, bromide. The metal halide may be a transition metal halide or other metal halide. Transition metal chlorides include halides of titanium, tantalum, niobium, tin, tungsten and antimony. Other suitable metal halide catalysts include boron trifluoride.

[0049] In some embodiments, the fluorination catalyst is selected from SbF5, SbCl5, SbCl3, SnCl4, TaCl5, TiCl4, NbCl5, MoCl6, WCl6, antimony (V) chlorofluoride, 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 comprises tantalum pentachloride, antimony pentachloride, or antimony pentafluoride.

[0050] In the liquid phase fluorination process, hydrogen fluoride is present in a molar ratio of HF to 333jfa between 7:1 and 15:1. In one embodiment, hydrogen fluoride is present in a molar ratio of HF to 333jfa of about 10:1.

[0051] In some embodiments, the liquid phase fluorination process is conducted at a temperature between 50° C. and 160° C. In some embodiments, the temperature may be greater than 100° C. In other embodiments, the temperature may be less than 150° C.

[0052] In some embodiments, the liquid phase fluorination reaction is carried out at a pressure in the range of 0 psi to 600 psi (0 MPa to 4.1 MPa). In some embodiments, the reaction is carried out at substantially atmospheric pressure.

[0053] In some embodiments, the contact time for the liquid phase fluorination reaction is from about 1 minute to about 24 hours, or from about 10 minutes to about 12 hours, or from about 1 hour to about 6 hours.

[0054] When the process is carried out in a liquid medium by purging unreacted chlorine, distilling off unreacted 333jfa and filtering off the catalyst, the desired product HCFC-336mfa can be recovered from the reactor. When carried out in the liquid phase, if the catalyst is present in a sufficiently high concentration that the catalyst precipitates from the product mixture before, during or after distillation, the catalyst can be filtered off. Alternatively, the catalyst can remain in the distillation bottoms.

[0055] In some embodiments, the product mixture from the fluorination reaction may be subjected to recovery and purification steps. Such steps may include washing with water, drying, and distillation.

[0056] The product prepared in the gas phase or liquid phase fluorination process may include CF3CCl2CH2CF3 (336mfa) and additional compounds selected from CF3CCl2CH2CFCl2, CHF2CH2CCl2CF3 and mixtures thereof.

[0057] Preparation of 1,1,1,4,4,4-hexafluoro-2-butyne

[0058]

[0059] The present disclosure also provides a method comprising contacting HCFC-336mfa with a base to prepare a product mixture containing 1,1,1,4,4,4-hexafluoro-2-butyne (CF3C≡CCF3) in a dehydrochlorination reaction, as shown in Scheme (3). The base is preferably an alkaline aqueous medium. The reaction step is preferably carried out in the presence of a phase transfer catalyst.

[0060] Solution 3

[0061] The base is an alkaline aqueous medium, including an aqueous solution of an alkali metal hydroxide or an alkali metal halide salt or other alkali. The base can be selected from hydroxides, oxides, carbonates or phosphates of alkali metals and 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.

[0062] In some embodiments, the alkaline aqueous solution has a pH of more than 8. In some embodiments, the alkaline aqueous solution has a pH of more than 10. In some embodiments, the alkaline aqueous solution has a pH of 10-13. In some embodiments, the alkaline aqueous solution contains a small amount of organic liquid that is miscible or immiscible with water. In some embodiments, the liquid in the alkaline aqueous solution is at least 90% water. In some embodiments, the water is tap water; in other embodiments, the water is deionized or distilled.

[0063] This reaction step is preferably carried out in the presence of a phase transfer catalyst. As used herein, a phase transfer catalyst is intended to represent a substance that is conducive to the transfer of ionic compounds from the aqueous phase to the organic phase. In this step, the organic phase comprises the HCFC-336mfa reactant, and the aqueous phase comprises an alkaline aqueous medium. The phase transfer catalyst is conducive to the reaction of these different and incompatible components. Although various phase transfer catalysts can work in different ways, their mechanism of action does not determine their effectiveness in the method of the present disclosure, provided that the phase transfer catalyst is conducive to the dehydrochlorination reaction.

[0064] Suitable phase transfer catalysts include quaternary alkyl ammonium 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 alkyl ammonium salt contains at least 8 carbon atoms. An example of an alkyl quaternary ammonium salt in which three alkyl groups contain at least 8 carbon atoms is manufactured by ALfaAesar-Fisher Scientific under the trade name N-methyl-N,N,N-trioctylammonium chloride is marketed as 336. Examples of alkyl quaternary ammonium salts in which the four alkyl groups contain at least 8 carbon atoms include tetraoctylammonium salts.

[0065] The anion of such salts may be a halide such as chloride or bromide, hydrogen sulfate or any other commonly used anion.

[0066] Specific quaternary alkyl ammonium salts include tetraoctylammonium chloride, tetraoctylammonium hydrogen sulfate, tetraoctylammonium bromide, methyltrioctylammonium chloride, methyltrioctylammonium bromide, tetradecylammonium chloride, tetradecylammonium bromide, and tetradodecylammonium chloride.

[0067] According to one embodiment, a method for preparing a product mixture comprising CF3C≡CCF3 comprises contacting 336mfa with a base and a phase transfer catalyst under reaction conditions effective to achieve a conversion of 336mfa of at least 50% per hour.

[0068] In other embodiments, the alkyl group of the alkyl quaternary ammonium salt comprises 4 to 10 carbon atoms, and the nonionic surfactant is present in an aqueous alkaline medium. According to this type of embodiment, the phase transfer catalyst and reaction conditions can effectively achieve the conversion of HCFC-336mfa, preferably at least 20% / hour. The anion of the alkyl quaternary ammonium salt wherein the alkyl group comprises 4 to 10 carbon atoms can be a halogen ion such as chloride or bromide, bisulfate or any other commonly used anion. The above-mentioned alkyl quaternary ammonium salt can be used in this embodiment, provided that their alkyl group comprises 4 to 10 carbon atoms. Specific additional salts include tetrabutylammonium chloride, tetrabutylammonium bromide and tetrabutylammonium hydrogen sulfate.

[0069] Preferred nonionic surfactants include ethoxylated nonylphenol or ethoxylated C12-C15 straight chain fatty alcohols. Useful nonionic surfactants include those available from Stepan Company (Northfield, IL) N25-9 and 10.

[0070] In some embodiments, the alkyl quaternary ammonium salt is added in an amount of 0.5 mol% to 2 mol% of HCFC-336mfa. In other embodiments, the alkyl quaternary ammonium salt is added in an amount of 1 mol% to 2 mol% of HCFC-336mfa. In other embodiments, the alkyl quaternary ammonium salt is added in an amount of 1 mol% to 1.5 mol% of HCFC-336mfa. In some embodiments, the amount of the alkyl quaternary ammonium salt added is 1 mol% to 1.5 mol% of HCFC-336mfa, and the weight of the nonionic surfactant added is 1 to 2 times the weight of the alkyl quaternary ammonium salt. These amounts apply to each of the above-mentioned embodiments of the alkyl quaternary ammonium salt used.

[0071] In some embodiments, the reaction mixture is heated to a temperature between 50°C and 95°C, preferably the reaction is carried out at a temperature between about 60°C and 90°C, most preferably at 70°C.

[0072] In some embodiments, the reaction system is heated for about 1 hour to about 10 hours, about 2 hours to about 6 hours, about 4 hours to about 5 hours, and combinations thereof.

[0073] In some embodiments, the reaction is carried out at substantially atmospheric pressure.

[0074] In some embodiments, the base comprises a strong base. In some embodiments, the base comprises sodium hydroxide or potassium hydroxide.

[0075] 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 may be sodium or potassium. The halide may be a chloride or a bromide. A preferred alkali metal halide salt is sodium chloride. Without being bound by any specific theory, it is believed that the alkali metal halide salt stabilizes the phase transfer catalyst. Although the dehydrochlorination reaction itself produces alkali metal chlorides, particularly sodium chloride, if sodium hydroxide is used as a base, the addition of additional sodium chloride provides other effects of increasing the yield of 1,1,1,4,4,4-hexafluoro-2-butyne. In some embodiments, alkali metal halides are added in an amount of about 25 to about 100 equivalents per mole of phase transfer catalyst. In other embodiments, alkali metal halides are added in an amount of about 30 to about 75 equivalents per mole of phase transfer catalyst. In other embodiments, alkali metal halides are added in an amount of about 40 to about 60 equivalents per mole of phase transfer catalyst. These amounts apply to each of the above-mentioned quaternary alkyl ammonium salts.

[0076] The product 1,1,1,4,4,4-hexafluoro-2-butyne (boiling point: -25°C) can be recovered from the product mixture by distillation, wherein butyne evaporates from the aqueous medium and can then be condensed.

[0077] Preparation of Z-1,1,1,4,4,4-hexafluoro-2-butene

[0078] The present disclosure also 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 product mixture comprising Z-1,1,1,4,4,4-hexafluoro-2-butene (Z-1336mzz), as shown in Scheme (4): the process is preferably carried out in the presence of a hydrogenation catalyst (which is an alkyne to olefin catalyst).

[0079]

[0080] In some embodiments, the hydrogenation catalyst is a palladium catalyst, such as a catalyst comprising palladium dispersed on alumina or titanium silicate and doped with silver and / or lanthanide. The loading of palladium dispersed on alumina or titanium silicate is relatively low. In some embodiments, the palladium loading is from about 100 ppm to about 5000 ppm. In other embodiments, the palladium loading is from about 200 ppm to about 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 from about 2: 1 to about 3: 1. In some embodiments, the molar ratio of silver to palladium is about 0.5: 1.0.

[0081] In some embodiments, the hydrogenation catalyst comprises Lindlar (5% Pd on CaCO3 poisoned with lead). The lead compound may be lead acetate, lead oxide, or any other suitable lead compound.

[0082] The Lindela catalyst may be further deactivated or conditioned with quinoline. The amount of palladium on the support is typically about 5% by weight, but may be any catalytically effective amount. In some embodiments, the amount of palladium on the support in the Lindela catalyst is greater than 5% by weight. In other embodiments, the amount of palladium on the support may be about 5% by weight to about 1% by weight.

[0083] In some embodiments, the amount of catalyst used is about 0.5% to about 4% by weight of the amount of 1,1,1,4,4,4-hexafluoro-2-butyne. In other embodiments, the amount of catalyst used is about 1% to about 3% by weight of the amount of butyne. In other embodiments, the amount of catalyst used is about 1% to about 2% by weight of the amount of butyne.

[0084] In some embodiments, the amount of catalyst used is about 0.5% to about 4% by weight of the amount of 1,1,1,4,4,4-hexafluoro-2-butyne. In other embodiments, the amount of catalyst used is about 1% to about 3% by weight of the amount of butyne. In other embodiments, the amount of catalyst used is about 1% to about 2% by weight of the amount of butyne.

[0085] 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 alcohol solvents include ethanol, isopropanol and n-propanol. In other embodiments, the solvent is a fluorocarbon or a 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.

[0086] In some embodiments, the reaction of 1,1,1,4,4,4-hexafluoro-2-butyne with hydrogen preferably adds hydrogen in batches, with the pressure of the container increasing by no more than about 100 psi (0.69 MPa) at each addition. In other embodiments, the addition of hydrogen is controlled so that the pressure in the container increases by no more than about 50 psi (0.35 MPa) at each addition. In some embodiments, hydrogen may be added in larger increments for the remainder of the reaction after sufficient hydrogen has been consumed in the hydrogenation reaction to convert at least 50% of the butynes ​​into Z-1336mzz. In other embodiments, hydrogen may be added in larger increments for the remainder of the reaction after sufficient hydrogen has been consumed in the hydrogenation reaction to convert at least 60% of the butynes ​​into the desired butenes. In other embodiments, hydrogen may be added in larger increments for the remainder of the reaction after sufficient hydrogen has been consumed in the hydrogenation reaction to convert at least 70% of the butynes ​​into the desired butenes. In some embodiments, the larger hydrogen addition increment may be 300 psi (2.07 MPa). In other embodiments, larger hydrogen addition increments may be 400 psi (2.76 MPa).

[0087] In some embodiments, the molar ratio is about 1 mole of hydrogen to about 1 mole of 1,1,1,4,4,4-hexafluoro-2-butyne. In other embodiments, the molar ratio of hydrogen to butyne is about 0.9 moles to about 1.3 moles. In other embodiments, the amount of hydrogen added is about 0.95 moles of hydrogen to about 1.1 moles of butyne. In other embodiments, the amount of hydrogen added is about 0.95 moles of hydrogen to about 1.03 moles of butyne.

[0088] In some embodiments, the hydrogenation is carried out at ambient temperature (15°C to 25°C). In other embodiments, the hydrogenation is carried out at above ambient temperature. In other embodiments, the hydrogenation is carried out at below ambient temperature. In other embodiments, the hydrogenation is carried out at a temperature below about 0°C.

[0089] In some embodiments, the reaction vessel containing hexafluoro-2-butyne and the catalyst is cooled to about -78°C under reduced pressure. The temperature of the reactor may then be allowed to warm to room temperature. Hydrogen may then be slowly added to the reaction vessel. In some embodiments, the rate of addition of hydrogen is adjusted to result in a pressure change in the reaction vessel of less than 70 psi, less than 60 psi, and / or less than 50 psi. Hydrogen may continue to be added until a slight excess of hydrogen is provided to the reaction vessel.

[0090] In one embodiment of the continuous process, a mixture of 1,1,1,4,4,4-hexafluoro-2-butyne and hydrogen is passed through a reaction zone containing a catalyst. A reaction vessel such as a metal tube filled with a catalyst can be used to form the reaction zone. In some embodiments, the molar ratio of hydrogen to butyne is about 1:1. In other embodiments of the continuous process, the molar ratio of hydrogen to butyne is less than 1:1. In other embodiments, the molar ratio of hydrogen to butyne is about 0.67:1.0.

[0091] In some embodiments of the continuous process, the reaction zone is maintained at ambient temperature. In other embodiments of the continuous process, the reaction zone is maintained at a temperature of 30°C. In other embodiments of the continuous process, the reaction zone is maintained at a temperature of about 40°C.

[0092] In some embodiments of the continuous process, the flow rate of 1,1,1,4,4,4-hexafluoro-2-butyne and hydrogen is maintained to provide a residence time of about 30 seconds in the reaction zone. In other embodiments of the continuous process, the flow rate of butyne and hydrogen is maintained to provide a residence time of about 15 seconds in the reaction zone. In other embodiments of the continuous process, the flow rate of butyne and hydrogen is maintained to provide a residence time of about 7 seconds in the reaction zone.

[0093] It should be understood that by increasing the flow rate of 1,1,1,4,4,4-hexafluoro-2-butyne and hydrogen flowing into the reaction zone, the contact time in the reaction zone is reduced. As the flow rate increases, this will increase the amount of butyne hydrogenated per unit time. 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.

[0094] In some embodiments, after the batch or continuous hydrogenation process is completed, Z-1336mzz can be recovered by any conventional method (including, for example, fractional distillation). In other embodiments, after the batch or continuous hydrogenation process is completed, Z-1336mzz has sufficient purity and does not require further purification steps.

[0095] The 1,1,1,4,4,4-hexafluoro-2-butene reaction product can be recovered in high yield and purity by distillation of the reaction mixture. In some embodiments, the yield of the reaction of Scheme 4 is greater than 95%, greater than 96%, greater than 97% and / or greater than 98%.

[0096] Example

[0097] The concepts described herein will be further described in the following examples, which do not limit the scope of the disclosure described in the claims.

[0098] Iron powder, vinylidene chloride, Tween 336 and sodium hydroxide were purchased from Sigma Aldrich (St. Louis, MO).

[0099] 113a 1,1,1-Trichloro-2,2,2-trifluoroethane (CF3CCl3), 2-chloro-3,3,3-trifluoropropene (CF3CCl=CH2), hydrogen fluoride and SbCl5 were purchased from Synquest Labs, Inc.

[0100] Example 1 (Comparative Example). Step 1: VDC insertion of 113a to prepare CF3CCl2CH2CCl3

[0101] Vinylidene chloride (26 g, 0.265 mol) was added to a mixture of 113a (100 g, 0.53 mol), Fe powder (0.62 g, 0.011 mol) and triphenylphosphine (1.41 g, 0.0054 mol) in a 240 mL Hastelloy reactor. The reactor was heated up to 150° C. for 5 hours. The mixture was transferred to a container and analyzed by GC: 24% GC yield (30% conversion and 80% selectivity to the product).

[0102] Example 2. Step 1: VDC insertion of 113a to prepare CF3CCl2CH2CCl3

[0103] In a 100 mL stainless steel autoclave, a mixture of vinylidene chloride (2.4 g, 0.025 mol) and 113a (23 g, 0.125 mol) was heated up to 100° C. for 24 hours along with 3 mL of propionitrile in the presence of anhydrous copper (II) chloride (0.34 g, 0.0025 mol). The mixture was transferred to a container and analyzed by GC: 32% GC yield (40% conversion, 80% selectivity to the product).

[0104] Example 3 (Comparative Example). Step 1: Insertion of 2-chloro-3,3,3-trifluoropropene into CCl4 to prepare CF3CCl2CH2CCl3

[0105] In a 300 mL Hastelloy reactor, a mixture of 2-chloro-3,3,3-trifluoropropene (32.6 g, 0.25 mol) and CCl4 (77 g, 0.5 mol) was heated up to 130° C. for 5 hours in the presence of Fe powder (0.62 g, 0.011 mol) and triphenylphosphine (1.40 g, 0.005 mol). The mixture was transferred to a container and analyzed by GC: the conversion was 55% and the selectivity to the product was 86%.

[0106] Example 4. Step 1: Insertion of 2-chloro-3,3,3-trifluoropropene into CCl4 to prepare CF3CCl2CH2CCl3

[0107] In a 100 mL stainless steel autoclave, a mixture of 2-chloro-3,3,3-trifluoropropene (3.3 g, 0.025 mol) and CCl4 (7.7 g, 0.05 mol) was heated up 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. The mixture was purified by fractional distillation and the distillation yield of the product was 62%.

[0108] The product CF3CCl2CH2CCl3 was recovered from the product mixture of Examples 1-4 and had the following characteristics: boiling point of 56°C to 58°C (13 mm Hg); 1H NMR (CDCl3): δppm 3.72 (CH2, s); 19F NMR (CDCl3): δppm-80.47 (CF3, s); MS (m / z): 248.75 (M+-Cl), 246.75 (M+-Cl-2H).

[0109] Example 5. Step 2: Liquid Phase Fluorination of CF3CCl2CH2CCl3 Using Antimony Catalyst to Prepare CF3CCl2CH2CF3(336mfa)

[0110] 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) in a PTFE-lined container was stirred at 110°C. The reaction mixture was poured into crushed ice. The organic layer was washed with water (twice) and dried over MgSO4. Distillation at 65°C to 68°C gave 1.9 g of product (81% yield). The product was recovered and had the following characteristics: 1H NMR (CDCl3): δ ppm 3.15 (q, JHF = 9.4 Hz, CH2); 19F NMR (CDCl3): δ ppm: -62.7 (t, JFH = 9.4 Hz, 2F, CH2CF3), -83.2 (s, 3F, CF3).

[0111] Example 6. Step 2: Liquid Phase Fluorination of CF3CCl2CH2CCl3 Using Tantalum Catalyst to Prepare CF3CCl2CH2CF3(336mfa)

[0112] 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) in a PTFE-lined container was stirred at 130° C. The reaction mixture was poured into crushed ice. The organic layer was washed with water (twice) and dried over MgSO4. Distillation at 65° C. to 68° C. gave 2.1 g of product (88% yield).

[0113] Example 7. Step 2: Gas Phase Fluorination of CF3CCl2CH2CCl3 to Prepare CF3CCl2CH2CF3(336mfa)

[0114] Towards The tube (0.5 inch OD, 10 inch long, 0.034 inch wall thickness) was filled with 6cc Newport chromium catalyst. The reactor was heated to the target temperature. CF3CCl2CH2CCl3 (4.27 mL / h) was fed via an ISCO pump and the vaporizer was controlled at 170°C. The HF / CF3CCl2CH2CCl3 molar ratio was 10 and the contact time was 10 seconds. The reaction was run at 0 psig. Using The reactor effluent was analyzed online by 6890GC / 5973MS to show that the conversion of the feedstock was 95%, the selectivity to 336mfa was 70%, and the selectivity to 1326mxz (CF3CCl=CHCF3) was 30%.

[0115] Example 8. Step 3: Use 336 Quaternary ammonium salt converts CF3CCl2CH2CF3 into hexafluoro-2-butyne

[0116] At room temperature, 336 quaternary ammonium salts (0.53g, 0.001325mol) in the presence of, NaOH aqueous solution (22mL, 0.22mol) is added to CF3CCl2CH2CF3 (23.5g, 0.1mol) and water (5.6mL).After adding, reaction temperature is raised to 70 ℃, and gas chromatography is used to monitor the reaction.Reaction is completed after 2 hours, and hexafluorobutyne is collected in the dry ice trap with greater than 90% yield.

[0117] Example 9. Step 3: Conversion of CF3CCl2CH2CF3 to hexafluoro-2-butyne using tetrabutylammonium bromide and surfactant

[0118] At room temperature, tetrabutylammonium bromide (0.45 g, 0.001325 mol) and 10 surfactant (0.7g), NaOH aqueous solution (22mL, 0.22mol) was added to 336mfa (23.5g, 0.1mol) and water (5.6mL). After addition, the reaction temperature was raised to 70°C and the reaction was monitored using gas chromatography. The reaction was completed after 4.5 hours, and hexafluorobutyne was collected in a dry ice trap with a yield of more than 90%.

[0119] Example 10. Step 4: Conversion of 1,1,1,4,4,4-hexafluorobutyne to (Z)-1,1,1,4,4,4-hexafluoro-2-butene

[0120] 5 g of Lindela (5% Pd on CaCO3 poisoned with lead) catalyst was charged to a 1.3 L shaking gas bottle. 480 g (2.96 mol) of hexafluoro-2-butyne was charged to the shaking gas bottle. The reactor was cooled to -78°C and evacuated. After the gas bottle warmed to room temperature, H2 was slowly added in increments not exceeding AP = 50 psi (0.35 MPa). A total of 3 moles of H2 was added to the reactor. Gas chromatography analysis of the crude product showed that the mixture consisted of CF3C≡CCF3 (0.236%), 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 reaction formed the Z-isomer with a selectivity of 96.98%. The Z-isomer was recovered by distillation.

[0121] Note that not all of the above-described actions are required in the general description or in the embodiments, a portion of a specific action may not be required, and one or more additional actions may be performed in addition to those described. Further, the order in which the actions are listed is not necessarily the order in which they are performed.

[0122] Beneficial effects, other advantages, and solutions to problems have been described above with reference to specific embodiments. However, the beneficial effects, advantages, solutions to problems, and any features that may cause any beneficial effect, advantage, or solution to occur or become more apparent are not to be construed as key, necessary, or essential features of any or all of the claims.

[0123] It should be understood that certain features described in the context of separate embodiments herein for clarity may also be provided in combination in a single embodiment. Conversely, various features described in the context of a single embodiment for simplicity may also be provided individually or in any secondary combination. In addition, references to values ​​described in ranges include each value within the range.

[0124] Although the method disclosed herein has been described with reference to preferred embodiments, it will be appreciated by those skilled in the art that various changes may be made and elements thereof may be substituted with equivalents without departing from the scope of the present disclosure. In addition, various modifications may be made to adapt a particular situation or a particular material to the teachings of the present disclosure without departing from the essential scope of the present disclosure.

Claims

1. A process for preparing a product mixture comprising 1,1,1,3,3-pentachloro-4,4,4-trifluorobutane (CCl3CH2CCl2CF3), the process comprising 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 (CF3CCl3, 113a) and carbon tetrachloride (CCl4), provided that when the halogenated alkane is 1,1,1-trichloro- When the halogenated alkane is carbon tetrachloride, the olefin is 2-chloro-3,3,3-trifluoropropene (CF3CCl=CH2, 1233xf); and further comprising contacting 1,1,1,3,3-pentachloro-4,4,4-trifluorobutane with HF in a gas phase or a liquid phase in the presence of a fluorination catalyst to form a product comprising 2,2-dichloro-1,1,1,4,4,4-hexafluorobutane.

2. The method according to claim 1, wherein the mononitrile is selected from acetonitrile, propionitrile, butyronitrile.

3. The method according to claim 2, wherein the mononitrile is propionitrile.

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

5. The process according to any one of claims 1 to 3, wherein the halogenated alkane is carbon tetrachloride and the olefin is 2-chloro-3,3,3-trifluoropropene.

6. The process according to any one of claims 1 to 3, wherein the molar ratio of mononitrile to catalyst is at least 10 and less than 25.

7. The process according to claim 6, wherein the molar ratio of mononitrile to catalyst is between 10 and 20.

8. The process according to claim 6, wherein the molar ratio of mononitrile to catalyst is between 15 and 20.

9. The process of claim 1 wherein the process of contacting 1,1,1,3,3-pentachloro-4,4,4-trifluorobutane with HF is performed in the gas phase.

10. The process of claim 1 wherein the process of contacting 1,1,1,3,3-pentachloro-4,4,4-trifluorobutane with HF is performed in the liquid phase.

11. The method of claim 1, further comprising contacting 2,2-dichloro-1,1,1,4,4,4-hexafluorobutane with a base to produce a product mixture comprising 1,1,1,4,4,4-hexafluoro-2-butyne (CF3C≡CCF3).

12. The process according to claim 11, wherein the process is carried out in the presence of a phase transfer catalyst.

13. The method of claim 12, wherein the phase transfer catalyst comprises a quaternary ammonium salt.

14. The method of claim 13, wherein the quaternary ammonium salt comprises tetrabutylammonium bromide or N-methyl-N,N,N-trioctylammonium chloride.

15. The method of claim 11, further comprising reacting 1,1,1,4,4,4-hexafluoro-2-butyne with hydrogen in the presence of a hydrogenation catalyst at an temperature sufficient to produce Z The product mixture of -1,1,1,4,4,4-hexafluoro-2-butene is contacted at a temperature and pressure of 1,1,1,4,4,4-hexafluoro-2-butene.

16. The method of claim 15, wherein the hydrogenation catalyst is a palladium catalyst.

17. The method of claim 16, wherein the palladium catalyst is a Lindela catalyst.

18. The method of claim 16, wherein the palladium catalyst comprises palladium dispersed on alumina or titanium silicate and doped with silver and / or lanthanides.

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