Processes for producing z-1,1,1,4,4,4-hexafluorobut-2-ene and intermediates for producing the same

Abstract

To provide intermediates useful to produce hydrofluoroolefins and manufacturing processes that provide hydrofluoroolefins that contain no chlorine.SOLUTION: There is provided processes for producing Z-1,1,1,4,4,4-hexafluoro-2-butene comprising: (a) contacting 1,1,2,4,4-pentachlorobuta-1,3-diene with HF to obtain a product mixture comprising 2-chloro-1,1,1,4,4,4-hexafluorobutane; (b) contacting (a) with a base to obtain a product mixture comprising E-1,1,1,4,4,4-hexafluoro-2-butene; (c) contacting (b) with a chlorine source to obtain a product mixture comprising 2,3-dichloro-1,1,1,4,4,4-hexafluorobutane; (d) contacting (c) with a base to obtain a product mixture comprising 1,1,1,4,4,4-hexafluoro-2-butyne; (e) contacting (d) with hydrogen to obtain a product mixture comprising Z-1,1,1,4,4,4-hexafluoro-2-butene.SELECTED DRAWING: None

Description

[Technical field]

[0001] Disclosure herein relates to processes for producing Z-1,1,1,4,4,4-hexafluoro-2-butene and intermediates useful in its production. The disclosure further provides processes for producing 2-chloro-1,1,1,4,4,4-hexafluorobutane, E-1,1,1,4,4,4-hexafluoro-2-butene, and 2,3-dichloro-1,1,1,4,4,4-hexafluorobutane. [Background technology]

[0002] Over the past several decades, many industries have been working to find alternatives to ozone depleting chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs). CFCs and HCFCs have been used in a wide range of applications, including use as refrigerants, cleaning agents, blowing agents for thermoplastic and thermoset foams, heat transfer media, gaseous dielectrics, aerosol propellants, fire extinguishing and suppression agents, power cycle working fluids, polymerization media, particulate removal fluids, carrier fluids, buffing abrasives, and displacement drying agents. In the search for alternatives to these versatile compounds, many industries have turned to the use of hydrofluorocarbons (HFCs). HFCs have zero ozone depletion potential and therefore will not be affected by the current regulatory phase-out as a result of the Montreal Protocol. Summary of the Invention [Problem to be solved by the invention]

[0003] In addition to the problem of ozone depletion, another environmental problem for many of these applications is global warming.Therefore, there is a need for compositions that meet low ozone depletion standards and have low global warming potential.It is believed that certain hydrofluoroolefins meet both of these goals.Therefore, there is a need for intermediates that are useful for producing hydrofluoroolefins and manufacturing processes that provide hydrofluoroolefins that do not contain chlorine.These materials have no ozone depletion potential and low global warming potential.

[0004] (Incorporated by reference) All publications, patents, and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference. In the case of conflict, the present application, including any definitions herein, will control. [Means for solving the problem]

[0005] The present disclosure provides a process for producing hydrofluoroolefin Z-1,1,1,4,4,4-hexafluorobut-2-ene (Z-HFO-1336mzz or Z-1336mzz), which comprises (a) contacting 1,1,2,4,4-pentachlorobuta-1,3-diene with HF in the presence of a fluorination catalyst in the liquid phase to produce a product mixture comprising 2-chloro-1,1,1,4,4,4-hexafluorobutane, (b) contacting the 2-chloro-1,1,1,4,4,4-hexafluorobutane with a base to produce a product mixture comprising E-1,1,1,4,4,4-hexafluorobut-2-ene (E-HFO-1336mzz or E-1336mzz), and (c) reacting the E-1,1,1,4,4,4-hexafluoro with HF in the liquid phase to produce a product mixture comprising 2-chloro-1,1,1,4,4,4-hexafluorobutane. (d) contacting the 2,3-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; and (e) contacting the 1,1,1,4,4,4-hexafluoro-2-butyne with hydrogen in the presence of a catalyst to produce a product mixture comprising Z-1,1,1,4,4,4-hexafluoro-2-butene.

[0006] In some embodiments, 1,1,2,4,4-pentachlorobuta-1,3-diene (HCC-2320az, 2320az) is produced according to a process that includes the dimerization of trichloroethylene (TCE). The process for producing 2320az includes contacting TCE in the presence of a catalyst to produce a product mixture that includes 2320az.

[0007] [ka]

[0008] In some embodiments, the dimerization of TCE is carried out in the presence of pentachloroethane (CCl3CHCl2, HCC-120), which accelerates the dimerization process.

[0009] In certain embodiments, 2320az is produced with at least 80% selectivity, and in some embodiments, the selectivity is greater than 90%, or greater than 95%, or greater than 99%, or greater than 99.5%. In certain embodiments, 2320az is recovered from the product mixture. In some embodiments, unreacted TCE is recovered and recycled. In some embodiments, pentachloroethane is recovered and recycled.

[0010] In some embodiments, 2-chloro-1,1,1,4,4,4-hexafluorobutane (HFC-346mdf or 346mdf) is produced by contacting 1,1,2,4,4-pentachlorobuta-1,3-diene (HCC-2320az or 2320az) with hydrogen fluoride (HF) in the liquid phase in the presence of a catalyst to produce a product mixture comprising 346mdf.

[0011] In the process of the present disclosure, 346mdf is contacted with a base to produce E-1,1,1,4,4,4-hexafluoro-2-butene (E-1336mzz).

[0012] In some embodiments, 2,3-dichloro-1,1,1,4,4,4-hexafluorobutane (CF3CHClCHClCF3) (HCFC-336mdd, 336mdd) is produced by contacting E-1336mzz with chlorine (Cl2), optionally in the presence of a catalyst, in the liquid or gas phase or using photoinitiation, to a product mixture comprising 336mdd.

[0013] In some embodiments, 336mdd is used in a process to produce 1,1,1,4,4,4-hexafluoro-2-butyne, the process comprising contacting 336mdd with a base. In some embodiments, the 1,1,1,4,4,4-hexafluoro-2-butyne is recovered and then reacted with hydrogen to form Z-1,1,1,4,4,4-hexafluoro-2-butene.

[0014] The present disclosure further provides compositions produced according to the processes disclosed herein. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] As used herein, the terms "comprises," "comprising," "includes," "including," "has," "having," or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, article, or apparatus that includes a list of elements is not necessarily limited to those elements but may also include other elements not expressly listed or inherent to such process, method, article, or apparatus.

[0016] When an amount, concentration, or other value or parameter is given as either a range, a preferred range, or a list of upper and / or lower preferred values, these are to be understood as specifically disclosing all ranges formed from any pair of any upper range limit or preferred value and any lower range limit or preferred value, whether or not the ranges are separately disclosed. When a numerical range is described herein, unless otherwise indicated, the range is intended to include its endpoints, and to include all integers and fractions within the range.

[0017] By "recovering" is meant, in the case of recovering E-1,1,1,4,4,4-hexafluoro-2-butene or Z-1,1,1,4,4,4-hexafluoro-2-butene useful as a starting material for a subsequent reaction step or, for example, as a refrigerant or a foam blowing agent or a solvent or a fire extinguishing agent or an electronic gas, sufficient isolation of the desired product is meant to make it available for its intended use.

[0018] The details of the recovery step 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 or incompatible with the subsequent reaction step, the recovery step may include separating the desired product from the product mixture including the reaction medium. This separation may be performed simultaneously with the contacting step when the desired product is volatile under the reaction conditions. Volatilization of the desired product may constitute isolation and thereby recovery of the desired product. If the vapor contains other materials that are intended to be separated from the desired product, the desired product may be separated, for example, by selective distillation.

[0019] The step of recovering the desired product from the product mixture preferably involves separating the desired product from the catalyst or other components of the product mixture used or produced in the process to produce the desired product.

[0020] The present disclosure provides, among other things, processes for producing E-1336mzz and Z-1336mzz. Starting materials can include 1,1,2,4,4-pentachlorobuta-1,3-diene, which can be produced from trichloroethylene, one process being as described herein.

[0021] Formation of 1,1,2,4,4-pentachlorobuta-1,3-diene (2320az) 1,1,2,4,4-Pentachlorobuta-1,3-diene (HCC-2320az or 2320az) may be produced according to the present disclosure by dimerization of trichloroethylene (TCE). In some embodiments, a process is provided for producing a product mixture comprising 2320az, the process comprising contacting TCE with a dimerization catalyst at an elevated temperature.

[0022] In some embodiments, the dimerization catalyst comprises iron. The iron dimerization catalyst may comprise metallic iron from any source (including a combination of sources) and may be or include iron powder, iron wire, iron mesh, or iron shavings. The iron catalyst may also include an iron salt, such as ferric chloride or ferrous chloride (FeCl3 or FeCl2, respectively).

[0023] In some embodiments, the dimerization catalyst comprises copper. The copper dimerization catalyst may comprise metallic copper from any source (including a combination of sources), and may be, for example, copper powder or copper wire. The copper catalyst may also comprise a cuprous or cupric salt, such as cuprous chloride or cupric chloride (CuCl or CuCl2, respectively).

[0024] The process is preferably carried out in an anhydrous environment, for example, if ferric chloride is used, the ferric chloride is preferably anhydrous.

[0025] In some embodiments, the dimerization catalyst has a specific concentration relative to the moles of TCE reactant used. Thus, in some embodiments where the catalyst comprises a metallic iron catalyst, the weight ratio of Fe wire (or Fe powder) catalyst to TCE is from about 0.0001 to about 1. In other embodiments, the weight ratio of iron catalyst to TCE is from about 0.01 to 1.

[0026] In some embodiments, the dimerization catalyst comprises ferric chloride and the weight ratio of ferric chloride to TCE is from about 0.00001 to about 1. For example, the weight ratio of ferric chloride to TCE is from about 0.00001 to about 0.002, while in other examples the weight ratio is from about 0.00005 to about 0.001. In yet other examples, the weight ratio of ferric chloride to TCE is from about 0.0001 to about 1, while in further examples the weight ratio of ferric chloride to TCE is from about 0.00015 to about 1.

[0027] In some embodiments, trichloroethylene is contacted with a dimerization catalyst and pentachloroethane. The pentachloroethane (HCC-120) accelerates the reaction to produce a product mixture that includes 2320az. In certain embodiments, the weight ratio of HCC-120 to TCE is about 0.001 to about 1. In other embodiments, the weight ratio of HCC-120 to TCE is about 0.005 to about 1.

[0028] The dimerization of TCE is carried out at an elevated temperature, for example, a temperature in the range of about 210 to about 235° C. The temperature may be greater than 200° C. The temperature may be less than 245° C.

[0029] The pressure is typically autogenous.

[0030] The contact (residence) time is typically about 0.5 to 10 hours.

[0031] In some embodiments, the conversion of TCE is at least 15%, or at least 30%, or at least 50%. In some embodiments, the selectivity to 2320az is at least 80%, or at least 85%, or at least 90%.

[0032] By-products in the dimerization reaction may include tetrachloroethane isomers, tetrachlorobutadiene isomers, hexachlorobutene isomers, trichloroethylene oligomers. The product mixture containing 2320az may further include E-1,1,2,3,4-pentachloro-1,3-butadiene or Z-1,1,2,3,4-pentachloro-1,3-butadiene. Thus, in one embodiment, there is a composition that includes 1,1,2,4,4-pentachlorobuta-1,3-diene, E-1,1,2,3,4-pentachlorobuta-1,3-diene, and Z-1,1,2,3,4-pentachlorobuta-1,3-diene.

[0033] The process may further include recovering 2320az from the product mixture prior to using the recovered 2320az as a starting material in processes to produce HCFC-346mdf, HFO-E-1336mzz, HCFC-336mdd, 1,1,1,4,4,4-hexafluoro-2-butyne, and HFO-Z-1336mzz, for example, as described herein.

[0034] The process for recovering 2320az from the product mixture may include one or any combination of purification techniques known in the art, such as distillation. "Recovering" 2320az from a product mixture produces a product that contains at least 95%, or at least 97%, or at least 99% 2320az.

[0035] In certain embodiments, the process for producing 2320az may further include recovering trichloroethylene from the product mixture and recycling the recovered trichloroethylene to the dimerization process described herein.

[0036] In certain embodiments, the process for producing 2320az may further include recovering hexachlorobutene isomers from the product mixture and recycling the recovered hexachlorobutene isomers to the dimerization process described herein.

[0037] In certain embodiments, the process for producing 2320az may further include recovering pentachloroethane from the product mixture and recycling the recovered pentachloroethane to the dimerization process described herein.

[0038] If present, other products such as E-1,1,2,3,4-pentachloro-1,3-butadiene and Z-1,1,2,3,4-pentachloro-1,3-butadiene may also be recovered.

[0039] Formation of 2-chloro-1,1,1,4,4,4-hexafluorobutane (HCFC-346mdf) According to the process provided herein, a process is provided that includes contacting 1,1,2,4,4-pentachlorobuta-1,3-diene (2320az) with HF in the presence of a catalyst in the liquid phase to produce a product mixture that includes HCFC-346mdf (346mdf).

[0040] Fluorination catalysts that can be used in the liquid phase process of the present invention include those derived from Lewis acid catalysts such as metal halides. The halides may be selected from fluorides, chlorides, and bromides, or combinations thereof. The metal halides may be transition metal halides or other metal halides. Transition metal chlorides include halides of titanium, zirconium, hafnium, tantalum, niobium, tin, molybdenum, tungsten, and antimony. Other suitable metal halide catalysts include boron trichloride, boron trifluoride, and arsenic trifluoride.

[0041] In some embodiments, the liquid phase fluorination can be carried out in a reaction zone, which can include any reaction vessel of suitable size for the scale of the reaction. In some embodiments, the reaction zone is a reaction vessel constructed of corrosion-resistant materials. In some embodiments, these materials include nickel-based alloys such as Hastelloy®, nickel-chromium alloys available from Special Metals Corp. under the trademark Inconel® (hereinafter "Inconel®") or nickel-copper alloys available from Special Metals Corp. (New Hartford, New York) under the trademark Monel®, or vessels lined with fluoropolymers. In other embodiments, the reaction vessel can be made of other materials of construction, including stainless steel, particularly the austenitic types, and copper-clad steel.

[0042] The molar ratio of HF to 2320az, in some embodiments, is from about 1 to about 35. In other embodiments, the molar ratio of HF to 2320az is from about 1 to about 25.

[0043] In some embodiments, the fluorination process is carried out at an elevated temperature, for example, a temperature in the range of 50-160° C. In some embodiments, the temperature may be greater than 100° C. In other embodiments, the temperature may be less than 150° C.

[0044] In some embodiments, the fluorination process is carried out at a pressure ranging from 0 to 600 psi (0 to 4.1 MPa).

[0045] In some embodiments, the residence time for the fluorination reaction may be from about 1 to about 25 hours. In other embodiments, the residence time for the fluorination reaction may be from about 2 to about 10 hours. In other embodiments, the residence time for the fluorination reaction may be from about 4 to about 6 hours.

[0046] In some embodiments, the product mixture including 346mdf may further include one or more of 1,2-dichloro-1,1,4,4,4-pentafluorobutane, Z-1,1,1,4,4,4-hexafluoro-2-chloro-2-butene, E-1,1,1,4,4,4-hexafluoro-2-butene, and 1,1-dichloro-2,2,4,4,4-pentafluorobutane. In one embodiment, there is a composition comprising 2-chloro-1,1,1,4,4,4-hexafluorobutane (346mdf), 1,2-dichloro-1,1,4,4,4-pentafluorobutane (345mfd), Z-1,1,1,4,4,4-hexafluoro-2-chloro-2-butene (Z-1326mxz), E-1,1,1,4,4,4-hexafluoro-2-butene (E-1336mzz), and 1,1-dichloro-2,2,4,4,4-pentafluorobutane (345mfc).

[0047] In some embodiments, the product mixture is a composition comprising 346mdf and includes 1,1,1,4,4,4-hexafluorobutane (356mff), 1,1,1-trifluoro-2-trifluoromethylbutane (356mzz), Z-1,1,1,4,4,4-hexafluoro-2-chloro-2-butene (Z-1326mxz), E-1,1,1,4,4,4-hexafluoro-2-chloro-2-butene (E-1326mxz), Z-1,1,1,4,4,4-hexafluoro-2,3-dichlorobutene (Z-1316mxx), and E-1,1,1,4,4,4-hexafluoro-2,3-dichlorobutene (E-1316mxx). In one embodiment, the product mixture containing 346mdf contains greater than 0 and less than 2 wt% each of 356mff and 356mmz, greater than 0 and less than 3 wt% Z-1326mxz, Z-1316mxx, and E-1316mxx, and greater than 0 and less than 5 wt% E-1326mxz. This composition is useful for producing E-1,1,1,4,4,4-hexafluoro-2-butene (E-1336mzz) as described herein.

[0048] In some embodiments, 346mdf is produced with greater than 90%, 92%, 94%, 95%, 96%, 97%, 98%, or 99% selectivity over other products.

[0049] The process may further include recovering 346mdf from the product mixture comprising 346mdf. Processes for recovering 346mdf include one or any combination of purification techniques known in the art, such as distillation. "Recovering" 346mdf from the product mixture produces a product comprising 346mdf that contains at least 98.5%, or at least 99, or at least 99.5% 346mdf.

[0050] In certain embodiments, the process for producing 346mdf may further include recovering 2320az from the product mixture and recycling the recovered 2320az to the fluorination process described herein.

[0051] In some embodiments, the process for producing 346mdf disclosed herein comprises: (a') contacting trichloroethylene in the presence of a dimerization catalyst to produce a product mixture comprising 2320az; and (a) contacting the 2320az produced in step (a') with hydrogen fluoride in the presence of a fluorination catalyst in the liquid phase to produce a product mixture comprising 346mdf. Optionally, after step (a') and prior to step (a), 2320az is recovered.

[0052] In some embodiments, the process for producing 346mdf disclosed herein comprises: (a') contacting trichloroethylene in the presence of a dimerization catalyst and pentachloroethane to produce a product mixture comprising 2320az; and (a) contacting the 2320az produced in step (a') with hydrogen fluoride in the presence of a fluorination catalyst in the liquid phase to produce a product mixture comprising 346mdf. Optionally, after step (a') and prior to step (a), 2320az is recovered.

[0053] Variations of the process elements in steps (a') and (a) are disclosed herein above. The purity of 2320az is typically at least 97% prior to proceeding to step (a).

[0054] Preparation of (E)-1,1,1,4,4,4-hexafluorobut-2-ene (E-1336mzz) Further provided is a process herein comprising contacting 346mdf with a base to form a product mixture comprising E-1336mzz. The base is added in an amount effective to convert the 346mdf to E-1336mzz.

[0055] In some embodiments, the base is selected from lithium hydroxide, lithium oxide, sodium hydroxide, sodium oxide, potassium hydroxide, potassium oxide, rubidium hydroxide, rubidium oxide, cesium hydroxide, cesium oxide, calcium hydroxide, calcium oxide, strontium hydroxide, strontium oxide, barium hydroxide, and barium oxide. In some embodiments, the base is potassium hydroxide. In some embodiments, the base is sodium hydroxide. In some embodiments, the base is in an aqueous solution. In some embodiments, the concentration of the base in an aqueous solution is about 4M to about 12M.

[0056] In some embodiments, the process is carried out in the presence of a phase transfer catalyst. In some embodiments, the phase transfer catalyst is selected from quaternary ammonium salts, heterocyclic ammonium salts, organic phosphonium salts, and non-ionic compounds. In some embodiments, the phase transfer catalyst is selected from the group consisting of benzyltrimethylammonium chloride, benzyltriethylammonium chloride, methyltricaprylammonium chloride, methyltributylammonium chloride, methyltrioctylammonium chloride, dimethyldiphenylphosphonium iodide, methyltriphenoxyphosphonium iodide, tetrabutylphosphonium bromide, tetrabutylphosphonium chloride, hexadecyltributylphosphonium bromide, and DL-α-tocopherol methoxypolyethylene glycol succinate. In some embodiments, the phase transfer catalyst is methyltrioctylammonium chloride.

[0057] In some embodiments, the base is sodium hydroxide and the phase transfer catalyst is methyltrioctylammonium chloride.

[0058] In some embodiments, the product mixture further comprises one or more of hexafluoroisobutylene (1336mt), 1,1,1,4,4,4-hexafluorobutane (356mff), (E)-1-chloro-1,1,4,4,4-pentafluorobut-2-ene (1335lzz), and Z-CF3CH=CHCF3. In some embodiments, E-CF3CH=CHCF3 is produced in a yield of about 95% or greater. In some embodiments, E-CF3CH=CHCF3 is produced in a selectivity of about 99 mole % or greater relative to the other components of the mixture.

[0059] In one embodiment, the product mixture is a composition comprising E-1336mzz, greater than 0% and less than 1% by weight each of Z-1336mzz and 1,1,1,4,4,4-hexafluorobutane (356mff), greater than 0% and less than 0.5% by weight of 1,1,1-trifluoro-2-trifluoromethylbutene (1336mt, CF3(CF3)C=CH2), and greater than 0% and less than 0.2% by weight of 1-chloro-1,1,4,4,4-pentafluorobut-2-ene (1335lzz, CF2ClCH=CHCF3).

[0060] In one embodiment, the product mixture comprises E-1336mzz, greater than 0% and less than 1% by weight combined Z- and E-1,1,2,4,4,4-hexafluorobutene (Z- and E-1336mzy, CF2HCF=CHCF3), and greater than 0% and less than 0.5% by weight combined Z- and E-1,1,1,4,4,4-hexafluoro-2-chloro-2-butene (Z- and E-1326mxz). and greater than 0 wt.% and less than 0.2 wt.% combined Z- and E-1,1,1,4,4-pentafluoro-2-chlorobutene (Z- and E-1335mxz, CF2HCH=CClCF3), and greater than 0 wt.% and less than 0.2 wt.% combined Z- and E-1,1,1,4,4-pentafluoro-3-chlorobutene (Z- and E-1335mzx, CF2HCCl=CHCF3).

[0061] In one embodiment, the product mixture contains E-1336mzz and greater than 0% and less than 1% by weight each of 1,1,1,4,4,4-hexafluorobutane (356mff, CF3CH2CH2CF3), 1,1,1-trifluoro-2-trifluoromethylbutane (356mmz, (CF3)2CHCH3), and 1,1,4,4,4-pentafluoro-2-methylbut-1-ene (1345cm, CF3C and Z- and E-1,1,1,4,4,4-hexafluoro-2-chloro-2-butene (Z- and E-1326mxz) in a total amount greater than 0 weight % and less than 0.1 weight %. The composition comprises Z- and E-1,1,1,4,4,4-hexafluoro-2,3-dichlorobutene (Z- and E-1316mxx, CF3CCl=CClCF3) in a total amount greater than 0 weight % and less than 0.1 weight %.

[0062] In some embodiments of the processes provided herein, E-1336mzz is recovered from the product mixture.

[0063] Generation of HCFC-336mdd The reaction of E-1336mzz with a chlorine source to produce a product mixture comprising 2,3-dichloro-1,1,1,4,4,4-hexafluorobutane (CF3CHClCHClCF3, HCFC-336mdd) is a chlorination process in which a chlorine source reacts with E-1336mzz to produce a product mixture comprising the desired HCFC-336mdd product. The process may be carried out in the liquid phase in a liquid medium or in the gas phase, preferably in the presence of a chlorination catalyst or with photoinitiation, respectively. An example of a liquid medium is the E-1336mzz reactant itself.

[0064] Photoinitiation is carried out in a suitable photoinitiator apparatus comprising a light source, a chlorine (Cl2) source, and E-1336mzz (the material to be chlorinated), for example as described in WO 2006 / 069108 A1.

[0065] Examples of suitable chlorination catalysts include transition metal chlorides or Lewis acids such as aluminum chloride.

[0066] The catalyst for the chlorination process in the liquid phase may be selected from ferric chloride, chromium chloride, alumina chloride, cupric chloride, and combinations of two or more thereof. The catalyst for the chlorination process in the gas phase may be selected from ferric chloride, chromium chloride, alumina chloride, cupric chloride, and combinations of two or more thereof supported on carbon.

[0067] The temperature and pressure conditions of the chlorination process are preferably selected to be effective to produce HCFC-336mdd with high selectivity. In carrying out the process in the liquid phase, such as that supplied by E-1336mzz, the process is preferably carried out in a closed pressurized reactor in which the pressure is sufficient to maintain the liquid state. The pressure in the reactor may be autogenous or elevated pressure. When the process is carried out in a liquid medium, the desired product HCFC-336mdd can be recovered from the reactor by purging the unreacted chlorine and distilling off the unreacted E-1336mzz. If present in a high enough concentration to precipitate out of the product mixture before or during or after distillation, the catalyst can be filtered. Alternatively, the catalyst may remain in the distillation heel.

[0068] A tubular reactor may be used to carry out the process in the vapor state (phase). A chlorination catalyst, such as a Lewis acid, may be located within the reactor for effective contact with the E-1336mzz and chlorine source, which are simultaneously fed to the reactor at a temperature and residence time effective to produce the desired HCFC-336mdd reaction product at the desired selectivity. The temperature of the chlorination process is maintained by adding heat to the reactor. Preferably, the temperature of the process is in the range of 100° C. to 200° C. The pressure within the tubular reactor is preferably about 0.1 to 1 MPa. HCFC-336mdd may be recovered from the product mixture by distillation.

[0069] The chlorine source may be selected from chlorine, N-chlorosuccinimide, t-butyl hypochlorite, oxalyl chloride, and sulfuryl chloride.

[0070] In some embodiments, the reaction of E-1336mzz with a chlorine source is carried out in the presence of a chlorination catalyst and the chlorine source is chlorine (Cl2). In some embodiments, the reaction of E-1336mzz with a chlorine source is carried out in the absence of a chlorination catalyst and the chlorine source is chlorine (Cl2).

[0071] In certain embodiments, the reaction of E-1336mzz with a chlorine source is carried out using photoinitiation in the presence of ultraviolet radiation, and the chlorine source is chlorine.

[0072] In certain embodiments, the reaction of E-1336mzz with a chlorine source is carried out in the absence of a chlorination catalyst, and the chlorine source is N-chlorosuccinimide, t-butyl hypochlorite, oxalyl chloride, or sulfuryl chloride.

[0073] The process may further include recovering HCFC-336mdd from the product mixture to reduce other components of the product mixture. The process for recovering HCFC-336mdd may include one or any combination of purification techniques known in the art, such as distillation. By "recovering" HCFC-336mdd from the product mixture, a product is produced that contains at least 98.5%, or at least 99, or at least 99.5% HCFC-336mdd. In some embodiments, the E-1336mzz may be recovered and recycled back into the process or used for another purpose.

[0074] The chlorination of E-1336mzz preferably provides a selectivity to HCFC-336mdd of at least 85%, more preferably at least 90%, and most preferably at least 95%, regardless of whether the reaction is carried out in the liquid or gas phase.

[0075] The product mixture containing 336mdd may further contain one or more of HCFC-336mfa (2,2-dichloro-1,1,1,4,4,4-hexafluorobutane, CF3CCl2CH2CF3) and HCFC-326mda (2,3,3-trichloro-1,1,1,4,4,4-trifluoropropane, CF3CHClCCl2CF3), which may be recovered from the product mixture. Alternatively, the HCFC-336mfa and / or HCFC-326mda may be retained in the product mixture and carried forward to a subsequent process to produce hexafluoro-2-butyne.

[0076] In certain embodiments, the process for producing 336mdd may further include recovering unconverted E-1336mzz from the chlorination product mixture and recycling the recovered E-1336mzz to the chlorination process described herein.

[0077] In some embodiments, unconverted E-1336mzz is recovered from the product mixture, hi some embodiments, the E-1336mzz may be used for another purpose, such as a blowing agent or a heat transfer fluid.

[0078] Preparation of 1,1,1,4,4,4-hexafluoro-2-butyne The disclosure further provides a process comprising contacting HCFC-336mdd with a base in a dehydrochlorination reaction to produce a product mixture comprising 1,1,1,4,4,4-hexafluoro-2-butyne (CF3C≡CCF3). The base is preferably a basic aqueous medium. This reaction step is preferably carried out in the presence of a catalyst. Preferably, the basic aqueous medium comprises an aqueous solution of an alkali metal hydroxide or alkali metal halide salt or other base. Preferably, the catalyst is a phase transfer catalyst. As used herein, phase transfer catalyst is intended to mean a material that promotes the transfer of ionic compounds between an organic phase and an aqueous phase. In this step, the organic phase comprises the HCFC-336mdd reactants and the aqueous phase comprises the basic aqueous medium. The phase transfer catalyst promotes the reaction of these dissimilar and incompatible components.

[0079] Different phase transfer catalysts may function in different ways, but their mechanism of action does not limit their usefulness in the present invention, so long as the phase transfer catalyst promotes the dehydrochlorination reaction.

[0080] Preferred phase transfer catalysts are quaternary alkyl ammonium salts. In some embodiments, at least one alkyl group of the quaternary alkyl ammonium salt contains at least 8 carbons. Examples of quaternary alkyl ammonium salts in which three alkyl groups contain at least 8 carbon atoms include trioctylmethylammonium chloride. Aliquat® 336 is a commercially available phase transfer catalyst containing trioctylmethylammonium chloride. Examples of quaternary alkyl ammonium salts in which four alkyl groups contain at least 8 carbon atoms include tetraoctylammonium salts. The anion of such salts can be a halide such as chloride or bromide, hydrogen sulfate, or any other commonly used anion. Specific quaternary alkyl ammonium salts include tetraoctylammonium chloride, tetraoctylammonium hydrogen sulfate, tetraoctylammonium bromide, methyltrioctylammonium chloride, methyltrioctylammonium bromide, tetradecylammonium chloride, tetradecylammonium bromide, and tetradodecylammonium chloride. According to such embodiments, the phase transfer catalyst and reaction conditions are preferably effective to achieve at least 50% conversion of HCFC-336mdd per hour.

[0081] In other embodiments, the alkyl group of the quaternary alkyl ammonium salt contains 4-10 carbon atoms, and a non-ionic surfactant is present in the aqueous basic medium. According to such embodiments, the phase transfer catalyst and reaction conditions are preferably effective to achieve at least 20% conversion of HCFC-336mdd per hour. The anion of the quaternary alkyl ammonium salt, whose alkyl group contains 4-10 carbon atoms, may be a halide, such as chloride or bromide, hydrogen sulfate, or any other commonly used anion. The above quaternary alkyl ammonium salts may be used in this embodiment, provided that their alkyl groups contain 4-10 carbon atoms. Specific additional salts include tetrabutylammonium chloride, tetrabutylammonium bromide, and tetrabutylammonium hydrogen sulfate.

[0082] Preferred nonionic surfactants include ethoxylated nonylphenol or ethoxylated C 12 ~C 15 and straight chain fatty alcohols.Nonionic surfactants useful in the present invention include Bio-soft® N25-9 and Makon® 10, available from Stepan Company (Northfield, IL).

[0083] In some embodiments, the quaternary alkyl ammonium salt is added in an amount of 0.5 mole percent to 2 mole percent of the HCFC-336mdd. In other embodiments, the quaternary alkyl ammonium salt is added in an amount of 1 mole percent to 2 mole percent of the HCFC-336mdd. In still other embodiments, the quaternary alkyl ammonium salt is added in an amount of 1 mole percent to 1.5 mole percent of the HCFC-336mdd. In some embodiments, the quaternary alkyl ammonium salt is added in an amount of 1 mole percent to 1.5 mole percent of the HCFC-336mdd, and the weight of the nonionic surfactant added is 1 to 2 times the weight of the quaternary alkyl ammonium salt. These amounts apply to each of the above embodiments of the quaternary alkyl ammonium salt used.

[0084] In some embodiments, the reaction is carried out at a temperature of about 60-90°C, most preferably 70°C.

[0085] A basic aqueous medium is a liquid (whether a solution, dispersion, emulsion, suspension, etc.) that is primarily an aqueous liquid with a pH greater than 7. In some embodiments, the basic aqueous solution has a pH greater than 8. In some embodiments, the basic aqueous solution has a pH greater than 10. In some embodiments, the basic aqueous solution has a pH between 10 and 13. In some embodiments, the basic aqueous solution contains a small amount of an organic liquid that may be miscible or immiscible with water. In some embodiments, the liquid in the basic aqueous solution is at least 90% water. In some embodiments, the water is tap water, and in other embodiments, the water is deionized or distilled water.

[0086] The base is selected from hydroxides, oxides, carbonates, or phosphates of alkali metals, alkaline earth metals, and mixtures thereof, hi some embodiments, the base is selected from lithium hydroxide, sodium hydroxide, potassium hydroxide, calcium hydroxide, magnesium oxide, calcium oxide, sodium carbonate, trisodium phosphate, disodium hydrogen phosphate, sodium dihydrogen phosphate, tripotassium phosphate, dipotassium hydrogen phosphate, potassium dihydrogen phosphate, and mixtures thereof.

[0087] These embodiments of the basic aqueous medium and base apply to all of the phase transfer catalysts, amounts, and reaction conditions described above. The selectivity for the formation of 1,1,1,4,4,4-hexafluoro-2-butyne is preferably at least 85%.

[0088] In some embodiments, the dehydrochlorination reaction of 336mdd 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 chloride or bromide. A preferred alkali metal halide salt is sodium chloride. Without being bound to any particular theory, it is believed that the alkali metal halide salt stabilizes the phase transfer catalyst. Although the dehydrochlorination reaction itself produces an alkali metal chloride, particularly sodium chloride when sodium hydroxide is used as the base, the addition of additional sodium chloride has the added benefit of increasing the yield of 1,1,1,4,4,4-hexafluoro-2-butyne. In some embodiments, the alkali metal halide is added at about 25 to about 100 equivalents per mole of phase transfer catalyst. In other embodiments, the alkali metal halide is added at about 30 to about 75 equivalents per mole of phase transfer catalyst. In yet another embodiment, the alkali metal halide is added at about 40 to about 60 equivalents per mole of phase transfer catalyst. These amounts apply to each of the quaternary alkyl ammonium salts listed above.

[0089] 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 can be evaporated from the aqueous medium and then condensed. Additionally, the product mixture may also contain 1,1,1,4,4,4-hexafluoro-2-chloro-2-butene (HCFO-1326, Z isomer, E isomer, or mixtures thereof), which can be separated from the product mixture and recycled to the process steps including contacting HCFC-336mdd with a base in a dehydrochlorination reaction to produce a product mixture containing CF3C≡CCF3.

[0090] Preparation of Z-1,1,1,4,4,4-hexafluoro-2-butene The present disclosure further provides a hydrogenation process comprising contacting 1,1,1,4,4,4-hexafluoro-2-butyne with hydrogen to produce a product mixture comprising Z-1,1,1,4,4,4-hexafluoro-2-butene (Z-1336mzz), preferably carried out in the presence of a catalyst for the conversion of an alkyne to an alkene.

[0091] In some embodiments, the hydrogenation of 1,1,1,4,4,4-hexafluoro-2-butyne is carried out as a batch process in the liquid phase.

[0092] In some embodiments, the hydrogenation of 1,1,1,4,4,4-hexafluoro-2-butyne is carried out as a continuous process in the gas phase.

[0093] In some embodiments, the catalyst for alkyne to alkene is a palladium catalyst, such as palladium dispersed on aluminum oxide or titanium silicate doped with silver and / or lanthanides. The loading of palladium dispersed on aluminum oxide or titanium silicate is relatively low. In some embodiments, the loading of palladium is from about 100 ppm to about 5000 ppm. In other embodiments, the loading of palladium 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.

[0094] Another embodiment of the alkyne to alkane catalyst is Lindlar's catalyst, which is a heterogeneous palladium catalyst supported on a calcium carbonate support that has been deactivated or conditioned with a lead compound. The lead compound can be lead acetate, lead oxide, or any other suitable lead compound. In some embodiments, the catalyst is produced by reducing a palladium salt in the presence of a slurry of calcium carbonate, followed by the addition of the lead compound. In some embodiments, the palladium salt in palladium chloride.

[0095] In other embodiments, the Lindlar catalyst is further deactivated or conditioned with quinoline. The amount of palladium supported on the support is typically about 5% by weight, but can be any catalytically effective amount. In other embodiments, the amount of palladium supported on the support in the Lindlar catalyst is greater than 5% by weight. In yet other embodiments, the amount of palladium supported on the support can be from about 5% by weight to about 1% by weight.

[0096] In some embodiments, the amount of catalyst used is from 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 from about 1% to about 3% by weight of the amount of butyne. In yet other embodiments, the amount of catalyst used is from about 1% to about 2% by weight of the amount of butyne.

[0097] In some embodiments, the reaction step is a batch reaction and is carried out in the presence of a solvent. In one such embodiment, the solvent is an alcohol. Exemplary alcohol solvents include ethanol, i-propanol, and n-propanol. In other embodiments, the solvent is a fluorocarbon or hydrofluorocarbon. Exemplary fluorocarbons or hydrofluorocarbons include 1,1,1,2,2,3,4,5,5,5-decafluoropentane and 1,1,2,2,3,3,4-heptafluorocyclopentane.

[0098] 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 small increments, with each addition increasing the pressure in the vessel by no more than about 100 psi (0.69 MPa). In other embodiments, the addition of hydrogen is controlled such that each addition increases the pressure in the vessel by no more than about 50 psi (0.35 MPa). In some embodiments, hydrogen can be added in larger increments to the residue of the reaction after sufficient hydrogen has been consumed in the hydrogenation reaction to convert at least 50% of the butyne to Z-1336mzz. In other embodiments, hydrogen can be added in larger increments to the residue of the reaction after sufficient hydrogen has been consumed in the hydrogenation reaction to convert at least 60% of the butyne to the desired butene. In yet other embodiments, hydrogen can be added in larger increments to the residue of the reaction after sufficient hydrogen has been consumed in the hydrogenation reaction to convert at least 70% of the butyne to the desired butene. In some embodiments, the larger increment of hydrogen loading may be 300 psi (2.07 MPa), while in other embodiments, the larger increment of hydrogen loading may be 400 psi (2.76 MPa).

[0099] 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 yet other embodiments, the amount of hydrogen added is about 0.95 moles of hydrogen to about 1.1 moles of butyne. In yet other embodiments, the amount of hydrogen added is about 0.95 moles of hydrogen to about 1.03 moles of butyne.

[0100] 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 a temperature greater than ambient temperature. In yet other embodiments, the hydrogenation is carried out at a temperature less than ambient temperature. In yet other embodiments, the hydrogenation is carried out at a temperature less than about 0° C.

[0101] In an 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 a catalyst. A reaction vessel, such as a metal tube, may be used and packed with catalyst to form the reaction zone. In some embodiments, the molar ratio of hydrogen to butyne is about 1:1. In other embodiments of a continuous process, the molar ratio of hydrogen to butyne is less than 1:1. In yet other embodiments, the molar ratio of hydrogen to butyne is about 0.67:1.0.

[0102] In some embodiments of the continuous process, the reaction zone is maintained at ambient temperature. In another embodiment of the continuous process, the reaction zone is maintained at a temperature of 30° C. In yet another embodiment of the continuous process, the reaction zone is maintained at a temperature of about 40° C.

[0103] In some embodiments of the continuous process, the flow rates of 1,1,1,4,4,4-hexafluoro-2-butyne and hydrogen are maintained such that the residence time in the reaction zone is about 30 seconds. In other embodiments of the continuous process, the flow rates of butyne and hydrogen are maintained such that the residence time in the reaction zone is about 15 seconds. In yet other embodiments of the continuous process, the flow rates of butyne and hydrogen are maintained such that the residence time in the reaction zone is about 7 seconds.

[0104] It is understood that by increasing the flow rate of 1,1,1,4,4,4-hexafluoro-2-butyne and hydrogen entering the reaction zone, the residence time in the reaction zone is reduced. As the flow rate increases, the amount of butyne hydrogenated per unit time 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 in the reaction zone to maintain the desired temperature.

[0105] The contacting step conditions, including the selection of the catalyst, are preferably selected to produce Z-1336mzz with a selectivity of at least 85%, more preferably at least 90%, and most preferably at least 95%.

[0106] In some embodiments, upon completion of the batch or continuous isomerization process, Z-1336mzz can be recovered through any conventional process, including, for example, fractionation. Unconverted hexafluoro-2-butyne may be recovered and recycled to the hydrogenation process. In other embodiments, upon completion of the batch or continuous hydrogenation process, Z-1336mzz has sufficient purity such that no further purification steps are required. EXAMPLES

[0107] material Trichloroethylene, chlorine, ferric chloride, TaCl5, pentachloroethane (HCC-120), tetra-n-butylammonium bromide (TBAB), trioctylmethylammonium chloride (Aliquat® 336), NaOH, and Lindlar's catalyst are available from Sigma Aldrich (St. Louis, MO). Hydrogen fluoride was purchased from Synquest Labs, Inc. (Alachua, FL). Makon® 10 non-ionic surfactant is available from Stepan Company (Northfield, IL).

[0108] GC analyses of Examples 1-4 were carried out using an Agilent® 5975 GC, RESTEK Rtx-1 column.

[0109] Example 1: Preparation of 1,1,2,4,4-pentachlorobuta-1,3-diene (HCC-2320az) Trichloroethylene (100 g, 0.76 mol) was added to a shaker tube containing 30 mg of anhydrous FeCl3. The reaction mixture was heated at 230° C. for 2 h. The reactor contents were cooled to room temperature and analyzed by GC to determine conversion and selectivity. The results are provided in Table 1.

[0110] Example 2: Preparation of 1,1,2,4,4-pentachlorobuta-1,3-diene (HCC-2320az) Trichloroethylene (100 g, 0.76 mol) was added to a shaker tube containing 1 g of iron wire. The reaction mixture was heated at 230° C. for 2 hours. The reactor contents were cooled to room temperature and analyzed by GC to determine conversion and selectivity. The results are provided in Table 1.

[0111] Example 3: Preparation of 1,1,2,4,4-pentachlorobuta-1,3-diene (HCC-2320az) Trichloroethylene (100 g, 0.76 mol) was added to a shaker tube containing 20 mg of anhydrous FeCl3 and 1 g of HCC-120. The reaction mixture was heated at 230° C. for 2 h. The reactor contents were cooled to room temperature and analyzed by GC to determine conversion and selectivity. The results are provided in Table 1.

[0112] Example 4: Preparation of 1,1,2,4,4-pentachlorobuta-1,3-diene (HCC-2320az) Trichloroethylene (100 g, 0.76 mol) was added to a shaker tube containing 1 g of iron wire and 1 g of HCC-120. The reaction mixture was heated at 230° C. for 2 hours. The reactor contents were cooled to room temperature and analyzed by GC to determine conversion and selectivity. The results are provided in Table 1.

[0113] [Table 1]

[0114] As can be seen from Table 1, the presence of HCC-120 increases the conversion of trichloroethylene to 2320az when FeCl3 or Fe wire catalyst is used.

[0115] Example 5: Preparation of 2-chloro-1,1,1,4,4,4-hexafluorobutane (HCFC-346mdf) TaCl5 (12.5 g) was added to a 210 mL Hastelloy® C reactor, followed by HF (49 g). The reaction mixture was heated to 150° C. for 1 h and cooled to 0° C. HCC-2320az (26 g) was added to the reactor and the reaction was heated back to 130° C. The reaction rate was indicated by the pressure increase. Level-off pressure indicates completion of the reaction. After aqueous workup and phase separation, the product mixture was analyzed by GC, which showed 100% conversion of starting material and 98% selectivity to product HCFC-346mdf.

[0116] Example 6: Preparation of E-CFCH=CHCF (E-1336mzz) Aqueous NaOH solution (6 mL, 0.06 mol) was added to 346mdf (10 g, 0.05 mol) and water (6.8 mL) in the presence of 0.27 g of methyltrioctylammonium chloride (Aliquat® 336) at room temperature (RT). After the addition, the reaction temperature was raised to 70° C. and the reaction was monitored using gas chromatography. After 2 hours, 7.2 g of product E-CF3CH=CHCF3 (E-1336mzz) was collected in a dry ice trap (E-1336mzz selectivity: 99.4%, yield: 95.4%).

[0117] Example 7: Preparation of E-CFCH=CHCF (E-1336mzz) Aqueous KOH solution (6 mL, 0.06 mol) was added to 346mdf (10 g, 0.05 mol) and water (6.8 mL) at room temperature (RT). After the addition, the reaction temperature was raised to 70° C. and the reaction was monitored using gas chromatography. After 2 h, 7.6 g of product E-1336mzz was collected in a dry ice trap (E-1336mzz selectivity: 99.5%, yield: 96%).

[0118] The product composition is shown in Table 2 below and contains greater than 99% E-1336mzz.

[0119] [Table 2]

[0120] Comparative Example: Preparation of E-CF3CH=CHCF3 (E-1336mzz) An aqueous solution of NaOH (6 mL, 0.06 mol) was added to 346mdf (10 g, 0.05 mol) and water (6.8 mL) at room temperature (RT). After the addition, the reaction temperature was raised to 70° C. and the reaction was monitored using gas chromatography. After 2 h, 0.1 g of the product E-CF3CH=CHCF3 (E-1336mzz) was collected in a dry ice trap (yield: <1%).

[0121] Example 8: Liquid Phase Preparation of 2,3-Dichloro-1,1,1,4,4,4-Hexafluorobutane (HCFC-336mdd) In this example, E-1336mzz is catalytically and thermally chlorinated in the liquid phase to produce HCFC-336mdd using a Lewis acid catalyst.

[0122] The liquid phase reaction was carried out in a Hast® C reactor. The liquid medium was the E-1336mzz reactant. When used, the catalyst was present in the liquid phase. The reactor contents were transferred to a cylinder and analyzed by GC to determine conversion and selectivity. HCFC-336mdd was recovered from the reaction by purging unreacted chlorine, distilling off unreacted E-1336mzz, and filtering the catalyst. The reaction conditions and results are shown in Table 3.

[0123] [Table 3]

[0124] For each of Examples 8-1 through 8-6, E-1336mzz (20 g, 0.122 mol) and chlorine (8.65 g, 0.122 mol) were heated to the specified temperature in a Hast® C reactor in the presence of FeCl3, CrCl3, AlCl3, or CuCl2 catalyst (0.4 g, 0.0025 mol) for the specified time. The specified temperature and specified time are provided in Table 3.

[0125] For Examples 8-7 and 8-8, E-1336mzz (20 g, 0.122 moles) and chlorine (8.65 g, 0.122 moles) were heated in a 210 mL Hastelloy® C reactor over a period of 2 hours to the temperature specified in Table 3. No catalyst was present.

[0126] Comparison of the results of Examples 8-1 through 8-8 indicates a preference for reactions carried out in the presence of a catalyst and at temperatures of at least 130°C or at least 150°C.

[0127] Example 9: Gas-phase preparation of 2,3-dichloro-1,1,1,4,4,4-hexafluorobutane (HCFC-336mdd) The procedure for the gas phase reaction was as follows: An Inconel® tube (0.5 inch OD, 15 inch length, 0.34 inch wall thickness) was charged with 2 cc (1.10 gm) of ferric chloride on acid washed Takeda® carbon. The reactor was heated to 125°C in a Lindberg furnace and fed with CF3CH=CHCF3 (E-1336mzz) at 2.42-4.83 mL / hr and chlorine gas at 6.2-13.0 sccm (standard cubic centimeters per minute) through a vaporizer controlled at 80°C. Over the course of the run, the temperature was increased to 175°C. All of the following experiments were carried out at 49-51 psig (0.34-0.35 MPa). The reactor effluent was analyzed on-line using an Agilent® 6890 GC / 5973 MS and a Restek® PC2618 5% Krytox® CBK-D / 60 / 80 6 meter x 2 mm ID 1 / 8" OD packed column purged with 30 sccm helium. HCFC-336mdd was recovered by distillation.

[0128] The data are shown in Table 4. Samples are taken at hourly intervals.

[0129] [Table 4]

[0130] In Table 4, 236fa (HFC-1,1,1,3,3,3-hexafluoropropane) and 123 (HCFC-2,2-dichloro-1,1,1-trifluoroethane) are impurities in the feed to the reactor.

[0131] The reaction conditions provide a residence time of 27-29 seconds with a reactor temperature of 175° C., giving high selectivity in the production of HCFC-336mdd.

[0132] Example 10: Preparation of 2,3-dichloro-1,1,1,4,4,4-hexafluorobutane (HCFC-336mdd) In this example, the reaction is photoinitiated.

[0133] A 50 gallon (190 L) stirred reaction vessel was equipped with a cooling jacketed column, an overhead condenser, a dip tube, and a quartz light well equipped with a 450 watt mercury arc lamp bulb.

[0134] The reactor was charged with 158 kg of E-1336mzz and the liquid was cooled to 0° C. The agitator was turned on at 100 rpm, the overhead condenser was cooled to approximately −20° C., and the lights were turned on. 69 kg of chlorine was slowly added to the system through a dip tube over a period of 51 hours, using feed rates to control temperature and pressure. The liquid reaction temperature and pressure were not allowed to exceed 10° C. and 1 psig (0.07 MPa), respectively.

[0135] After the chlorine addition was complete, the lights were turned off and the solution was allowed to warm to room temperature. The system was vented to ambient through a caustic scrubber and the crude reaction mixture was de-inventoried into a storage vessel. HCFC-336mdd recovery was accomplished by combining three batches of the resulting crude reaction mixture (663 Kg / 422 L) and then slowly adding the crude reaction mixture through a dip tube to a 200 gallon (750 L) stirred vessel equipped with a bottom discharge valve and charging with 80 gallons (300 L) of 10% aqueous K2HPO4 / KH2PO4. After the addition, the mixture was stirred vigorously for 3 hours and then the stirring was stopped. The lower organic phase was then decanted from the reactor to determine phase change using conductivity measurements. The resulting neutralized organic oil was a water-white liquid with a pH of 5-6 and was passed through a bed of molecular sieves to dryness and stored for final purification. The yield of isolated chemical over seven batches was 98%. The resulting GC assay (% FID) was 93.5% of the two 336mdd diastereomers (336mdd-dl and 336mdd-meso), with the remainder of the assay being about 6% heavy unknowns presumed to be oligomers of the product / starting material, giving a reaction selectivity of 93.5%. Final purification was achieved by distillation.

[0136] Example 11. Preparation of 1,1,1,4,4,4-hexafluoro-2-butyne HCFC-336mdd was produced using the vapor phase process described in Example 9 according to the specific information in Table 4, resulting in a selectivity of 99.4% to HCFC-336mdd.

[0137] At room temperature, aqueous NaOH solution (22 mL, 0.22 mol) was added to HCFC-336mdd (23.5 g, 0.1 mol) and water (5.6 mL) in the presence of trioctylmethylammonium chloride Aliquat® 336 (0.53 g, 0.001325 mol). After the addition, the reaction temperature was raised to 70° C. and the reaction was monitored using gas chromatography. The reaction was completed after 2 hours, and 14 g of 1,1,1,4,4,4-hexafluoro-2-butyne product (conversion: 100%; yield: 86%) was collected in a dry ice trap. The butyne was purified by distillation.

[0138] Example 12: Preparation of Z-1,1,1,4,4,4-hexafluoro-2-butene 1,1,1,4,4,4-Hexafluoro-2-butyne produced according to Example 11 was reacted with hydrogen to produce the desired Z isomer of 1,1,1,4,4,4-hexafluoro-2-butene by the following procedure: 5 g of Lindlar (5% Pd supported on lead-poisoned CaCO3) catalyst was charged to a 1.3 L rocker bomb. 480 g (2.96 moles) of hexafluoro-2-butyne was charged to the rocker. The reactor was cooled (-78°C) and evacuated. After warming the bomb to room temperature, H2 was added slowly in increments not exceeding Δp = 50 psi (0.35 MPa). A total of 3 moles of H2 was added to the reactor. Gas chromatographic analysis of the crude product showed that the mixture consisted of CF3C≡CCF3 (0.236%), the trans isomer E-CF3CH=CHCF3 (0.444%), saturated CF3CH2CH2CF3 (1.9%), CF2=CHCl, an impurity derived from the starting butyne (0.628%), and the cis isomer Z-CF3CH=CHCF3 (96.748%).

[0139] Distillation of the crude product gave 287 g (59% yield) of 100% pure cisCF3CH=CHCF3 (bp 33.3 °C). MS: 164 [MI], 145 [M-19], 95 [CF3CH=CH], 69 [CF3]. NMR H 1 : 6.12 ppm (multiplet), F 19: -60.9 ppm (triplet J = 0.86 Hz). The selectivity of this reaction towards the formation of the Z isomer was 96.98%. The Z isomer was recovered by distillation.

[0140] Other embodiments 1. The present disclosure relates to a process for producing Z-1,1,1,4,4,4-hexafluorobut-2-ene, the process comprising: (a) contacting 1,1,2,4,4-pentachlorobuta-1,3-diene with HF in the presence of a fluorination catalyst in the liquid phase to produce a product comprising 2-chloro-1,1,1,4,4,4-hexafluorobutane; (b) contacting the 2-chloro-1,1,1,4,4,4-hexafluorobutane with a base to produce a product comprising E-1,1,1,4,4,4-hexafluoro-2-butene; and (c) reacting the E-1,1,1,4,4,4 (d) contacting the 2,3-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; and (e) contacting the 1,1,1,4,4,4-hexafluoro-2-butyne with hydrogen to produce a product comprising Z-1,1,1,4,4,4-hexafluoro-2-butene. 2. The process described in embodiment 1 may further include contacting trichloroethylene in the presence of a dimerization catalyst to produce a product mixture comprising 1,1,2,4,4-pentachlorobuta-1,3-diene. 3. The process described in embodiment 1 may further include contacting trichloroethylene and pentachloroethane in the presence of a dimerization catalyst to produce a product mixture comprising 1,1,2,4,4-pentachlorobuta-1,3-diene. 4. The process according to embodiment 2 or 3 can produce a product mixture comprising 1,1,2,4,4-pentachlorobuta-1,3-diene and trichloroethylene. 5. The process described in embodiment 4 may further include recovering trichloroethylene and recycling it to the process described in embodiment 2. 6. The dimerization catalyst according to any of embodiments 2-5 may contain iron or copper. 7. The process of any of embodiments 2-6 may further include recovering 1,1,2,4,4-pentachlorobuta-1,3-diene from the product mixture and recycling the recovered 1,1,2,4,4-pentachlorobuta-1,3-diene to step (a). 8. The process of any of embodiments 2-7, wherein the dimerization catalyst comprises metallic iron. 9. The process of any of embodiments 2-7, wherein the dimerization catalyst comprises ferric chloride. 10. The process of any of embodiments 2-7, wherein the dimerization catalyst comprises copper metal. 11. The process of any of embodiments 2-7, wherein the dimerization catalyst comprises cuprous chloride or cupric chloride. 12. In the process of any embodiment 3, the weight ratio of pentachloroethane to trichloroethylene is from about 0.001 to about 1, or from about 0.005 to about 1. 13. The process of any of the preceding embodiments 1-12, wherein the fluorination catalyst in step (a) is a Lewis acid catalyst. 14. The process of any of the preceding embodiments 1-13, wherein the molar ratio of HF to 1,1,2,4,4-pentachlorobuta-1,3-diene in step (a) is from about 1 to about 35. 15. The process of any of the preceding embodiments 1-14, wherein the product mixture of step (a) comprises 1,2-dichloro-1,1,4,4,4-pentachlorobutane. 16. The process of any of the preceding embodiments 1-15, wherein the base in step (b) is selected from lithium hydroxide, lithium oxide, sodium hydroxide, sodium oxide, potassium hydroxide, potassium oxide, rubidium hydroxide, rubidium oxide, cesium hydroxide, cesium oxide, calcium hydroxide, calcium oxide, strontium hydroxide, strontium oxide, barium hydroxide, and barium oxide. 17. The process of any of the preceding embodiments 1-16, wherein step (b) is conducted in the presence of a phase transfer catalyst. 18. In the process according to embodiment 17, the phase transfer catalyst is selected from quaternary ammonium salts, heterocyclic ammonium salts, organic phosphonium salts, and non-ionic compounds. 19. The process of any of the preceding embodiments 1-18, wherein step (c) is conducted in a liquid phase. 20. The process of any of the preceding embodiments 1-18, wherein step (c) is conducted in the gas phase. 21. The process of any of the preceding embodiments 1-20, wherein the chlorine source in step (c) is chlorine. 22. The process of any of the preceding embodiments 1-21, wherein the base is a basic aqueous medium in step (d). 23. The process of any of the preceding embodiments 1-22, wherein step (d) is conducted in the presence of a phase transfer catalyst. 24. The process of any of the preceding embodiments 1-23, wherein step (d) is carried out in the presence of an alkali metal halide salt. 25. The process of any of the preceding embodiments 1-24, wherein the catalyst in step (e) is a catalyst for the conversion of an alkyne to an alkene. 26. In the process according to embodiment 25, the catalyst for the conversion of alkynes to alkenes is a palladium catalyst dispersed on silver and / or lanthanide doped aluminum oxide or titanium silicate. 27. In the process according to embodiment 26, the palladium loading is from 100 ppm to 5000 ppm. 28. In the process according to embodiment 26 or 27, the palladium catalyst is doped with at least one of silver, cerium, or lanthanum. 29. In the process according to embodiment 25, the catalyst for the conversion of alkynes to alkenes is a Lindlar catalyst. 30. In any of the preceding embodiments 1-29, the process further comprises recovering 2-chloro-1,1,1,4,4,4-hexafluorobutane from the product mixture of step (a) prior to step (b), or recovering E-1,1,1,4,4,4-hexafluoro-2-butene from the product mixture of step (b) prior to step (c), or recovering 2,3-dichloro-1,1,1,4,4,4-hexafluorobutane from the product mixture of step (c) prior to step (d), or recovering 1,1,1,4,4,4-hexafluoro-2-butyne hexafluorobutane from the product mixture of step (d) prior to step (e), or recovering Z-1,1,1,4,4,4-hexafluoro-2-butene from the product mixture of step (e). 31. The disclosure provides a process for producing E-1,1,1,4,4,4-hexafluorobut-2-ene, the process comprising: (a) contacting 1,1,2,4,4-pentachlorobuta-1,3-diene with HF in the presence of a fluorination catalyst in the liquid phase to produce a product comprising 2-chloro-1,1,1,4,4,4-hexafluorobutane; and (b) contacting the 2-chloro-1,1,1,4,4,4-hexafluorobutane with a base to produce a product comprising E-1,1,1,4,4,4-hexafluoro-2-butene. 32. The disclosure provides a process for producing Z-1,1,1,4,4,4-hexafluorobut-2-ene, the process comprising: (a) contacting 1,1,2,4,4-pentachlorobuta-1,3-diene with HF in the presence of a fluorination catalyst in the liquid phase to produce a product comprising 2-chloro-1,1,1,4,4,4-hexafluorobutane; and (b) contacting the 2-chloro-1,1,1,4,4,4-hexafluorobutane with a base to produce a product comprising E-1,1,1,4,4,4-hexafluoro-2-butene. 33. The process according to embodiment 32 may further comprise contacting trichloroethylene in the presence of a dimerization catalyst to produce a product mixture comprising 1,1,2,4,4-pentachlorobuta-1,3-diene. 34. The process according to embodiment 32 may further comprise contacting trichloroethylene and pentachloroethane in the presence of a dimerization catalyst to produce a product mixture comprising 1,1,2,4,4-pentachlorobuta-1,3-diene. 35. The process according to embodiment 33 or 34 can produce a product mixture comprising 1,1,2,4,4-pentachlorobuta-1,3-diene and trichloroethylene. 36. The process of embodiment 35 may further include recovering trichloroethylene and recycling it to the process of embodiment 2. 37. The dimerization catalyst according to any of embodiments 33-36 may contain iron or copper. 38. The process of any of embodiments 33-37 may further include recovering 1,1,2,4,4-pentachlorobuta-1,3-diene from the product mixture and recycling the recovered 1,1,2,4,4-pentachlorobuta-1,3-diene to step (a). 39. The process according to any of embodiments 33 to 38, wherein the dimerization catalyst comprises metallic iron. 40. The process of any of embodiments 33-38, wherein the dimerization catalyst comprises ferric chloride. 41. The process of any of embodiments 33-38, wherein the dimerization catalyst comprises metallic copper. 42. The process of any of embodiments 33-38, wherein the dimerization catalyst comprises cuprous chloride or cupric chloride. 43. In the process of any embodiment 34, the weight ratio of pentachloroethane to trichloroethylene is from about 0.001 to about 1, or from about 0.005 to about 1. 44. The process of any of the preceding embodiments 32-43, wherein the fluorination catalyst in step (a) is a Lewis acid catalyst. 45. In any of the preceding embodiments 32-44, the molar ratio of HF to 1,1,2,4,4-pentachlorobuta-1,3-diene in step (a) is from about 1 to about 35. 46. ​​The process of any of the preceding embodiments 32-45, wherein the product mixture of step (a) comprises 1,2-dichloro-1,1,4,4,4-pentachlorobutane. 47. The process of any of the preceding embodiments 32-46, wherein the base in step (b) is selected from lithium hydroxide, lithium oxide, sodium hydroxide, sodium oxide, potassium hydroxide, potassium oxide, rubidium hydroxide, rubidium oxide, cesium hydroxide, cesium oxide, calcium hydroxide, calcium oxide, strontium hydroxide, strontium oxide, barium hydroxide, and barium oxide. 48. The process of any of the preceding embodiments 32-47, wherein step (b) is conducted in the presence of a phase transfer catalyst. 49. In the process according to embodiment 48, the phase transfer catalyst is selected from quaternary ammonium salts, heterocyclic ammonium salts, organic phosphonium salts, and non-ionic compounds.

[0141] Although the present invention has been described in conjunction with its detailed description, it should be understood that the foregoing description is intended to illustrate and not to limit the scope of the invention as defined by the appended claims. Other aspects, advantages, and modifications are within the scope of the following claims. It should be understood by those skilled in the art that the present invention can be combined with any of the features described herein with respect to any particular aspect and / or embodiment of the invention, with any one or more of the other features of any other aspect and / or embodiment of the invention described herein, with appropriate modifications to ensure compatibility of the combination. Such combinations are considered to be part of the invention contemplated by this disclosure.

Claims

[Claim 1] A process for producing Z-1,1,1,4,4,4-hexafluoro-2-butene, comprising the steps of: (a) contacting 1,1,2,4,4-pentachlorobuta-1,3-diene with HF in the presence of a catalyst in the liquid phase to produce a product mixture comprising 2-chloro-1,1,1,4,4,4-hexafluorobutane; (b) contacting 2-chloro-1,1,1,4,4,4-hexafluorobutane with a base to produce a product mixture comprising E-1,1,1,4,4,4-hexafluoro-2-butene; (c) contacting E-1,1,1,4,4,4-hexafluoro-2-butene with a chlorine source in the presence of a catalyst to produce a product mixture comprising 2,3-dichloro-1,1,1,4,4,4-hexafluorobutane; (d) contacting 2,3-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; (e) contacting 1,1,1,4,4,4-hexafluoro-2-butyne with hydrogen to produce a product mixture comprising Z-1,1,1,4,4,4-hexafluoro-2-butene.

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