WO2009079525A2

WO2009079525A2 - Processes for the synthesis of 3-chloroperfluoro-2-pentene, octafluoro-2-pentyne, and 1,1,1,4,4,5,5,5-octafluoro-2-pentene

Info

Publication number: WO2009079525A2
Application number: PCT/US2008/087063
Authority: WO
Inventors: Mario Joseph Nappa
Original assignee: E.I. Du Pont De Nemours And Company
Priority date: 2007-12-17
Filing date: 2008-12-17
Publication date: 2009-06-25
Also published as: WO2009079525A3; JP2011506611A; CN101903313A; EP2220014A2

Abstract

Disclosed is a process comprising reacting CF3CF2CCI2CF2CF3 (CFC-41 -10mca) with hydrogen in the presence of a dehalogenation catalyst to produce CF3CF2CCI=CFCF3 (CFC-1419myx). Also disclosed herein is a process comprising reacting CF3CF2CCI=CFCF3 (CFC- 1419myx) with hydrogen in the presence of a dehalogenation catalyst to produce CF3CF2C=CCF3 (octafluoro-2-pentyne). Also disclosed herein is a process comprising reacting CF3CF2CCI2CF2CF3 (CFC-41 -10mca) with hydrogen in the presence of a dehalogenation catalyst to produce CF3CF2C=CCF3 (octafluoro-2-pentyne). In addition, a process for reacting CF3CF2C=CCF3, in a pressure vessel, with a Lindlar catalyst and hydrogen to produce CF3CF2CH=CHCF3 (1,1,1,4,4,5,5,5-octafluoro-2- pentene) is disclosed.

Description

TITLE

PROCESSES FOR THE SYNTHESIS OF 3-CHLOROPERFLUORO-2- PENTENE, OCTAFLUORO-2-PENTYNE, AND 1 ,1 ,1 ,4,4,5,5,5-OCTAFLUORO-

2-PENTENE

BACKGROUND FIELD OF THE DISCLOSURE

This disclosure relates to processes for synthesizing fluorocarbons. In particular, the processes are for synthesizing 3-chloroperfluoro-2-pentene, octafluoro-2-pentyne and 1 ,1 ,1 ,4,4,5,5,5-octafluoro-2-pentene.

DESCRIPTION OF THE RELATED ART

The fluorocarbon industry has been working for the past few decades to find replacement refrigerants for the ozone depleting chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) that are being phased out as a result of the Montreal Protocol. The solution for many applications has been the commercialization of hydrofluorocarbon (HFC) compounds for use as refrigerants, solvents, fire extinguishing agents, blowing agents and propellants. These new compounds, such as HFC refrigerants, HFC-134a being the most widely used at this time, have zero ozone depletion potential and thus are not affected by the current regulatory phase-out as a result of the Montreal Protocol.

In addition to ozone depleting concerns, global warming is another environmental concern in many of these applications. Thus, there is a need for compositions that meet both low ozone depletion standards as well having low global warming potentials. Certain hydrofluoroolefins are believed to meet both goals. There is a need for manufacturing processes that provide halogenated hydrocarbons and fluoroolefins that contain no chlorine that also have a low global warming potential.

SUMMARY OF THE INVENTION

The present disclosure provides a process comprising: reacting CF₃CF₂CCI₂CF₂CF₃ (CFC-41 -I Omca) with hydrogen in the presence of a dehalogenation catalyst to produce CF₃CF₂CCI=CFCF₃ (CFC-1419myx).

The present disclosure also provides a process comprising reacting CF₃CF₂CCI=CFCF₃ (CFC-1419myx) with hydrogen in the presence of a dehalogenation catalyst to produce CF₃CF₂C≡CCF₃ (octafluoro-2- pentyne).

The present disclosure also provides a process comprising: reacting CF₃CF₂CCI₂CF₂CF₃ (CFC-41 -10mca) with hydrogen in the presence of a dehalogenation catalyst to produce CF₃CF₂C≡CCF₃ (octafuoro-2-pentyne).

The present invention also provides a process comprising: reacting CF₃CF₂CCI₂CF₂CF₃ (CFC-41 -I Omca) with hydrogen in the presence of a dehalogenation catalyst to produce CF₃CF₂C≡CCF₃ (octafluoro-2-pentyne).

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Many aspects and embodiments have been described above and are merely exemplary and not limiting. After reading this specification, skilled artisans appreciate that other aspects and embodiments are possible without departing from the scope of the invention. Other features and benefits of any one or more of the embodiments will be apparent from the following detailed description, and from the claims.

Before addressing details of embodiments described below, some terms are defined or clarified.

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 comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Further, unless expressly stated to the contrary, "or" refers to an inclusive or and not to an exclusive or. For example, a condition A or B is satisfied by any one of the following: A is true (or present) and B is false (or not present), A is false (or not present) and B is true (or present), and both A and B are true (or present).

Also, use of "a" or "an" are employed to describe elements and components described herein. This is done merely for convenience and to give a general sense of the scope of the invention. This description should be read to include one or at least one and the singular also includes the plural unless it is obvious that it is meant otherwise.

Group numbers corresponding to columns within the Periodic Table of the elements use the "New Notation" convention as seen in the CRC Handbook of Chemistry and Physics, 81^st Edition (2000-2001 ).

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

As used herein, a reaction zone may be a reaction vessel fabricated from nickel, iron, titanium or their alloys, as described in U. S. Patent No. 6,540,933. A reaction vessel of these materials (e.g., a metal tube) may also be used. When reference is made to alloys, it is meant a nickel alloy containing from about 1 to about 99.9 weight percent nickel, an iron alloy containing about 0.2 to about 99.8 weight percent iron, and a titanium alloy containing about 72 to about 99.8 weight percent titanium. Of note is the use of a tube such as above, packed with a catalyst, wherein the tube is made of nickel or alloys of nickel such as those containing about 40 weight percent to about 80 weight percent nickel, e.g., Inconel™ 600 nickel alloy, Hastelloy™ C617 nickel alloy or Hastelloy™ C276 nickel alloy. The present invention is directed to three processes, one for making 3-chloroperfluoro-2-pentene (CF₃CF₂CCI=CFCF₃, CFC- 1419myx), one for making octafluoro-2-pentyne (CF₃CF₂C^CF₃), and one for making 1 ,1 ,1 ,4 ,4,5,5,5-octafluoro-2-pentene. 3-chloroperfluoro-2- pentene (CF₃CF₂CCI=CFCF₃, CFC-1419myx) and octafluoro-2-pentyne (CF₃CF₂C≡CCF₃), as well as 3,3-dichloro-perfluoropentane, may be used as intermediates to make 1 ,1 ,1 ,4,4,5,5,5-octafluoro-2-pentene.

In one embodiment, a process is provided comprising reacting CF₃CF₂CCI₂CF₂CF₃ (CFC-41 -10mca) with hydrogen in the presence of a dehalogenation catalyst to produce CF₃CF₂CCI=CFCF₃ (CFC-1419myx).

In one embodiment, the CFC-41 -10mca may be produced by an addition reaction of CFC-12 (CF₂CI₂, dichlorodifluoromethane) and TFE (tetrafluoroethylene, CF₂=CF₂) in the presence of a catalyst. In one embodiment, the catalyst for the addition reaction comprises an aluminum halide catalyst. The aluminum halide catalyst composition may have a bulk formula of AICI_xBr_yF_3-x-y wherein the average value of x is 0 to 3, the average value of y is 0 to 3-x, provided that the average values of x and y are not both 0. In another embodiment, x is from about 0.10 to 3.00 and y is 0. Aluminum halide compositions of this type are known; see U.S. Patent Nos. 5,157,171 and 5,162,594. In some cases CFC-1 14a may be employed in the formation of the aluminum halide composition. Thus, in some embodiments, use of sufficient excess of CFC-1 14a enables the production of AICI_XF₃-_X in s/ft/ from anhydrous aluminum chloride so that a fluorine-containing catalyst is obtained. Both CFC-12 and TFE are available commercially or may be prepared by methods known in the art.

The addition reaction involving CFC-12 and TFE is based on a stoichiometry of one mole of TFE per mole of CFC-12. However, an excess of either reactant may be used as desired. An excess of CFC-12 may reduce cycloaddition of TFE with itself. An excess of TFE may promote TFE-based by-products such as the cycloaddition reaction. Typically, the mole ratio of TFE to CFC-12 may range from about 3 to 1 to about 1 .5 to 1 . In one embodiment, the addition reaction step may be conducted in a continuous manner. In one embodiment, in the continuous mode, a mixture of CFC-12 and TFE may be passed through or over a bed or body of the aluminum halide composition (which may be under agitation) at suitable temperature and pressure to form a product stream, and the desired products (e.g., CFC-41-10mca) may be recovered from the stream by conventional methods such as fractional distillation.

In another embodiment, the addition reaction may be conducted in a batchwise manner. In one embodiment, in the batch process, the reactants and the aluminum halide composition may be combined in a suitable reactor to form a reaction mixture, and the mixture held at a suitable temperature and pressure (normally under agitation) until a desired degree of conversion is obtained. In one embodiment, the reactor is initially charged with the aluminum halide composition, and optionally with a diluent, then the CFC-12 and TFE are fed in the desired mole ratio (as separate streams or as a combined stream) into the reactor and maintained therein until the reaction is substantially complete. If the reactor is fed with CFC-12 and the aluminum halide composition are fed to the reactor in the substantial absence of the TFE, then the reactor and ingredients should be kept relatively cold (e.g., between about -78⁰C and 1 O⁰C) to discourage disproportionation of the CFC-12 to methanes having different fluorine content.

In one embodiment, the addition reaction may be practiced with a solvent or diluent for the CFC-12 and TFE. Typically, the CFC-12 and TFE are diluted; however, the diluent may be primarily the CFC-41 -1 Omca produced in the addition reaction. In some embodiments, solvents which may be used include CH₂CI₂, CHCI₃, CCI₄, CHCI₂CF₃, CCIF₂CCIF₂, and cyc/o-C₄CI₂F6 and mixtures thereof.

In one embodiment, the addition reaction zone temperature is typically in the range of from about 0⁰C to about 100⁰C. In another embodiment, the addition reaction zone temperature is in the range of from about 2O⁰C to about 8O⁰C. In one embodiment, the reaction pressure may vary widely. In another embodiment, the reaction is carried out at elevated pressures, particularly pressures generated autogenously in conformity with the reaction temperature employed. In certain embodiments, the pressure may be adjusted by controlling the amount of unreacted CFC-12 and TFE.

In one embodiment, at normally employed temperatures, the reaction time is typically between about 0.2 hour and 12 hours.

In one embodiment, the amount of aluminum halide composition employed is in the range of from about one to about twenty percent by weight based on the weight of the CFC-1 14a reactant.

In one embodiment, the effluent from the addition reaction zone (continuous or batch) typically includes CFC-41 -10mca, unreacted CFC- 12 and/or TFE, CCIF₂CF₂CF₂CI (CFC-216ca), and CCI₃CF₂CF₃ (CFC- 215cb). The effluent may also include one or more other by-products such as CCI₄ (CFC-10), CCI₃F (CFC-1 1 ), and C₃CI₄F₄ (CFC-214).

In one embodiment, the reaction products may be recovered from the reaction zone by use of a suitable conventional means such as by filtration and/or distillation. In another embodiment, in batch mode, it is normally convenient to separate the reaction products from the aluminum halide composition and to use the separated aluminum halide composition in subsequent batches.

Further details of the addition reaction described herein above may be found in U. S. Patent No. 6,229,058.

In one embodiment, the CFC-41-I Omca produced by the addition reaction as described above can be used to produce CFC-1419myx by catalytic dehalogenation.

In one embodiment the CFC-41 -10mca is separated from the effluent from the addition reaction zone. In another embodiment, CFC-41 - 10mca that is present in the effluent from the addition reaction zone is fed directly to a dehalogenation reaction zone to produce CFC-1419myx.

In other embodiments, CFC-41 -I Omca may be produced by other processes known in the art including processes disclosed in U.S. Patent No. 5,416,246, as well as other known processes. In one embodiment, the present disclosure also provides a process comprising reacting CF₃CF₂CCl₂CF₂CF₃ (CFC-41 -10mca) with hydrogen in the presence of a dehalogenation catalyst to produce CF₃CF₂CCI=CFCF₃ (CFC-1419myx). In one embodiment, the catalysts used for the process of converting

CFC-41 -10mca to CFC-1419myx may be a dehalogenation catalyst. Dehalogenation catalysts containing copper, nickel, chromium, palladium, and ruthenium are known in the art. They may be prepared by either precipitation methods or impregnation methods as generally described by Satterfield on pages 87-1 12 in Heterogeneous Catalysis in Industrial Practice, 2^nd edition (McGraw-Hill, New York, 1991 ).

In one embodiment, the catalyst for the dehalogenation is selected from the group consisting of copper on carbon, copper on calcium fluoride, palladium on barium sulfate, palladium/barium chloride on alumina, Lindlar catalyst (palladium on CaCO₃, poisoned with lead), copper and nickel on carbon, nickel on carbon, nickel on calcium fluoride, copper/nickel/chromium on calcium fluoride and unsupported alloys of copper and nickel.

In another embodiment, the catalyst is selected from the group consisting of copper on carbon, copper on calcium fluoride, copper and nickel on carbon, nickel on carbon, copper/nickel/chromium on calcium fluoride and unsupported alloys of copper and nickel. In one embodiment, the amount of copper on carbon or calcium fluoride support is from about 1 % by weight to about 25% by weight. In one embodiment, the carbon support may be acid washed carbon.

In another embodiment, the catalyst is palladium on barium sulfate catalyst that may contain from about 0.05% to 10% by weight palladium. In another embodiment, copper and nickel on carbon may contain from about 1 % to about 25% by weight copper and nickel combined on the carbon support. In certain embodiments, the carbon support may be any of the carbon supports as described previously herein for other catalysts. The weight ratio of the copper to nickel in the copper and nickel on carbon catalyst may range from about 2:1 to about 1 :2. In one embodiment, the palladium/barium chloride on alumina catalyst may contain from about 1 % to about 25% by weight barium chloride and from about 0.05% to about 10% by weight palladium relative to the total weight of the catalyst composition. Preparation of a palladium/barium chloride on alumina catalyst is described in U.S. Patent No. 5,243,103, the disclosure of which is herein incorporated by reference.

In one embodiment, the dehalogenation catalyst may be copper/nickel/chromium on calcium fluoride. In one embodiment, the molar ratio of copper : nickel : chromium oxide in the copper/nickel/chromium on calcium fluoride catalyst is from about 0 to about 1 copper, from about 0.5 to about 3.0 nickel, and from about 0 to about 2 chromium. In one embodiment, the molar ratio of copper : nickel : chromium in the copper/nickel/chromium on calcium fluoride catalyst is 1 .0 : 1 .0 : 1 .0. In another embodiment, the molar ratio is 1 .0 : 2.0 : 1 .0. In yet another embodiment, the molar ratio is 1 .0 : 2.0 : 0.25. In yet another embodiment, the molar ratio is 0.5 : 3.0 : 0.5. In yet another embodiment, the molar ratio is 0.5 : 0.5 : 2.0. In yet another embodiment, the molar ratio is 0 : 3.0 : 1 .0. In yet another embodiment, the molar ratio is 1 : 3.0 : 0. In one embodiment, the weight ratio of total catalyst material to support material may be from about 1 : 2 to about 2 : 1. Preparation of the copper/nickel/chrome catalyst is described in U.S. Patent No. 2,900,423.

In one embodiment, the unsupported alloys of copper and nickel include those described by Boudart in Journal of Catalysis, 81 , 204-13, 1983, the disclosure of which is herein incorporated by reference. In one embodiment, the mole ratio of Cu:Ni in the catalysts may range from about 1 :99 to about 99:1 . In another embodiment, the mole ratio of Cu:Ni is about 1 :1 .

In one embodiment, the dehalogenation reaction zone temperature is typically in the range of from about 200⁰C to about 500⁰C. In another embodiment, the addition reaction zone temperature is in the range of from about 300⁰C to about 450⁰C. In one embodiment, the dehalogenation reaction pressure may vary widely. In another embodiment, the reaction is carried out at elevated pressures.

In one embodiment, the molar ratio of hydrogen to organic (CFC- 41 -1 Omca) feed for the dehalogenation reaction ranges from about 0.5 : 1 to about 25:1 . In another embodiment, the molar ratio of hydrogen to organic feed ranges from about 1 .5:1 to about 2.5:1 .

In one embodiment of the dehalogenation reaction, the contact time for the process ranges from about 10 to about 120 seconds. Also provided herein is a process comprising reacting

CF₃CCI=CFCF₃ (CFC-1419myx) with hydrogen in the presence of a dehalogenation catalyst, thus producing CF₃C≡CCF₃ (hexafluoro-2- butyne).

In one embodiment, the CFC-1419myx may be further reacted with more hydrogen to produce hexafluoro-2-butyne (CF₃C≡CCF₃). This second dehalogenation reaction may be conducted under the same conditions and with the same catalysts as described above for the dehalogenation reaction for converting CFC-41 -I Omca to CFC-1419myx. In another embodiment, conditions may vary from the previous dehalogenation reaction in order to optimize production of octafluoro-2- pentyne and minimize undesirable by-products.

In another embodiment, the two reactions to produce hexafluoro-2- pentyne from CFC-41 -10mca may be conducted in a single step. Thus, the present invention further provides a process comprising reacting CF₃CF₂CCI₂CF₂CF₃ (CFC-41 -1 Omca) with hydrogen in the presence of a catalyst to produce CF₃CF₂C=CCF₃ (octafluoro-2-pentyne).

In one embodiment of a one step process to produce octafluoro-2- pentyne from CFC-41 -1 Omca, the reactor effluent may comprise CFC- 1419myx, octafluoro-2-pentyne, and any unreacted CFC-41 -1 Omca. The reaction effluent may optionally contain certain by-products such as CH₄, CHF₃ (HFC-23), CF₃CF=CFCF₂CF₃ (perfluoro-2-pentene, or pfp2), perfluorocyclopentene (CFC-C1418), CF₂=CCICF₃ (2- chloropentafluoropropene, or CFC-1215xc), 1 -hydroperfluorocyclopentene (HFC-C1427), CF₃CH=CCICF₃ (2-hydro-3-chlorohexafluoro-2-butene or HFC-1326), CF₃CH=CFCF₂CF₃ (2-hydroperfluoro-2-pentene or HFC- 1429), or mixtures thereof.

According to a further aspect of the present invention, there is provided a process for producing 1 ,1 ,1 ,4,4,5,5,5-octafluoro-2-pentene. In this process, the octafluoro-2-pentyne may be reacted further by a hydrogenation reaction to produce the 1 ,1 ,1 ,4,4,5,5,5-octafluoro-2- pentene. 1 ,1 ,1 ,4,4,5,5,5-octafluoro-2-pentyne may exist as one of two stereoisomers, E or Z (trans or cis respectively). In one embodiment of the hydrogenation reaction, the E isomer may be the predominant product. In another embodiment of the hydrogenation reaction, the Z isomer may be the predominant product. In yet another embodiment, the product of the hydrogenation reaction to produce 1 ,1 ,1 ,4,4,5,5,5-octafluoro-2- pentene from octafluoro-2-pentyne may produce essentially equimolar quantities of each of the E and Z isomers. As used herein, by predominant isomer is meant that the particular isomer is produced in greater than 50 mole percent. As used herein, by essentially equimolar quantities is meant that each of the E and Z isomer is produced at about 50 mole percent.

In one embodiment, the hydrogenation process comprises reacting 1 ,1 ,1 ,4,4,5,5, 5-octafluoro-2-pentyne, in a pressure vessel, with an hydrogenation catalyst and hydrogen to produce 1 ,1 ,1 ,4,4,5,5,5- octafluoro-2-pentene.

In one embodiment, the hydrogenation catalyst may comprise any hydrogenation catalyst known in the art. In another embodiment, the hydrogenation catalyst may comprise any metal hydrogenation catalyst. The metal catalysts may be supported or unsupported. In another embodiment, in particular, the hydrogenation catalyst may be any platinum group metal, including platinum, palladium, rhodium, and ruthenium. In another embodiment, the hydrogenation catalyst may comprise non- precious metal catalysts. In particular, the hydrogenation catalyst may comprise non-precious metal catalysts based on nickel (such as Raney nickel) and combinations of nickel with copper, manganese, zinc, and chromium. In yet another embodiment, the hydrogenation catalyst may comprise a Lindlar catalyst. A Lindlar catalyst is a heterogeneous palladium catalyst on a calcium carbonate support, which 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 one embodiment, the catalyst is prepared by reduction of a palladium salt in the presence of a slurry of calcium carbonate, followed by the addition of the lead compound. In one embodiment, the palladium salt in palladium chloride. In another embodiment, the catalyst is deactivated or conditioned with quinoline. The amount of palladium on the support is typically 5% by weight but may be any catalytically effective amount.

In one embodiment, the amount of the catalyst used is from about 0.5% by weight to about 4% by weight of the amount of the octafluoro-2- pentyne. In another embodiment, the amount of the catalyst used is from about 1 % by weight to about 3% by weight of the amount of the octafluoro- 2-pentyne. In yet another embodiment, the amount of the catalyst used is from about 1 % to about 2% by weight of the amount of the fluorinated octafluoro-2-pentyne.

In some embodiments, the hydrogenation reaction is conducted in a solvent. In one such embodiment, the solvent is an alcohol. Typical alcohol solvents include ethanol, /-propanol and n-propanol. In another embodiment, the solvent is a fluorocarbon or hydrofluorocarbon. Typical fluorocarbons or hydrofluorocarbons include 1 ,1 ,1 ,2,2,3,4,5,5,5- decafluoropentane and 1 ,1 ,2,2,3,3,4-heptafluorocyclopentane.

In one embodiment, the process is conducted in a batchwise process.

In another embodiment, the process is conducted in a continuous process in the gas phase.

In one embodiment, reaction of the octafluoro-2-pentyne with hydrogen in the presence of the catalyst may be done with addition of hydrogen in portions, with increases in the pressure of the vessel of no more than about 100 psi with each addition. In another embodiment, the addition of hydrogen is controlled so that the pressure in the vessel increases no more than about 50 psi with each addition. In one embodiment, after enough hydrogen has been consumed in the hydrogenation reaction to convert at least 50% of the octafluoro-2-pentyne to 1 ,1 ,1 , 4,4,5,5,5-octafluoro-2-pentene, hydrogen can be added in larger increments for the remainder of the reaction. In another embodiment, after enough hydrogen has been consumed in the hydrogenation reaction to convert at least 60% of the octafluoro-2-pentyne to 1 ,1 ,1 ,4,4,5,5,5- octafluoro-2-pentene, hydrogen can be added in larger increments for the remainder of the reaction. In yet another embodiment, after enough hydrogen has been consumed in the hydrogenation reaction to convert at least 70% of the octafluoro-2-pentyne to 1 ,1 ,1 ,4,4,5,5,5-octafluoro-2- pentene, hydrogen can be added in larger increments for the remainder of the reaction. In one embodiment, the larger increments of hydrogen addition can be 300 psi. In another embodiment, the larger increments of hydrogen addition can be 400 psi.

In one embodiment, the amount of hydrogen added is about one molar equivalent per mole of octafluoro-2-pentyne. In another embodiment, the amount of hydrogen added is from about 0.9 moles to about 1 .3 moles, per mole of octafluoro-2-pentyne. In yet another embodiment, the amount of hydrogen added is from about 0.95 moles to about 1 .1 moles, per mole of octafluoro-2-pentyne. In yet another embodiment, the amount of hydrogen added is from about 0.95 moles to about 1 .03 moles, per mole of octafluoro-2-pentyne.

In one embodiment, the hydrogenation is performed at ambient temperature. In another embodiment, the hydrogenation is performed at above ambient temperature. In yet another embodiment, the hydrogenation is performed at below ambient temperature. In yet another embodiment, the hydrogenation is performed at a temperature of below about 0° C.

In an embodiment of a continuous process, a mixture of octafluoro- 2-pentyne and hydrogen are passed through a reaction zone containing the catalyst. In one embodiment, the molar ratio of hydrogen to octafluoro-2-pentyne is about 1 :1 . In another embodiment of a continuous process, the molar ratio of hydrogen to octafluoro-2-pentyne is less than 1 :1. In yet another embodiment, the molar ratio of hydrogen to octafluoro- 2-pentyne is about 0.67:1.0. In one embodiment of a continuous process, the reaction zone is maintained at ambient temperature. In another embodiment of a continuous process, the reaction zone is maintained at a temperature of 30 ⁰C. In yet another embodiment of a continuous process, the reaction zone is maintained at a temperature of about 40 ⁰C.

In one embodiment of a continuous process, the flow rate of octafluoro-2-pentyne and hydrogen is maintained so as to provide a residence time in the reaction zone of about 30 seconds. In another embodiment of a continuous process, the flow rate of octafluoro-2-pentyne and hydrogen is maintained so as to provide a residence time in the reaction zone of about 15 seconds. In yet another embodiment of a continuous process, the flow rate of octafluoro-2-pentyne and hydrogen is maintained so as to provide a residence time in the reaction zone of about 7 seconds. It will be understood, that contact time in the reaction zone is reduced by increasing the flow rate of octafluoro-2-pentyne and hydrogen into the reaction zone. As the flow rate is increased this will increase the amount of octafluoro-2-pentyne being hydrogenated per unit time. Since the hydrogenation is exothermic, depending on the length and diameter of the reaction zone, and its ability to dissipate heat, at higher flow rates it may be desirable to provide a source of external cooling to the reaction zone to maintain a desired temperature.

In one embodiment of a continuous process, the amount of palladium on the support in the Lindlar catalyst is 5% by weight. In another embodiment, the amount of palladium on the support in the

Lindlar catalyst is greater than 5% by weight. In yet another embodiment, the amount of palladium on the support can be from about 5% by weight to about 1 % by weight.

In one embodiment, upon completion of a batch-wise or continuous hydrogenation process, the 1 ,1 ,1 ,4,4,5,5,5-octafluoro-2-pentene can be recovered through any conventional process, including for example, fractional distillation. In another embodiment, upon completion of a batch- wise or continuous hydrogenation process, the 1 ,1 ,1 , 4,4, 5,5,5-octafluoro- 2-pentene is of sufficient purity to not require further purification steps. EXAMPLES

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

Example 1

Synthesis of CFC-41 -I Omca (CFaCFpCCbCFpCFa)

A 400 ml Hastelloy™ C shaker tube was charged with 3 gm of aluminum chlorofluoride (AICI_XF₃-_X). The tube was sealed, cooled to -78⁰C, evacuated, purged with nitrogen three times, and charged with 50 gm (0.41 mole) of CCI₂F₂. The tube was then placed in a barricade and agitated. 25 gm (0.25 mole) of TFE were added and the tube was heated to 6O⁰C over the course of about 15 min; the pressure rose to 80 psig. The temperature was held at 6O⁰C for 1 .3 hr (pressure = 80-85 psig) and then raised to 8O⁰C and held for one hour (pressure = 112-116 psig). The next day the tube was discharged to afford 54.7 gm of clear supernatant over a brown solid. Analysis of the clear supernatant product by GCMS and ¹⁹F NMR indicated the composition shown in Table 1 .

TABLE 1

Example 2 Conversion of CFC-41 -I O-nnca to CFC-1419 mvx and octafluoro-2- pentyne

An Inconel™ tube (5/8 inch OD) was filled with 5 cc (6.54 gm) of Ni/Cu/Cι7CaF₂ pellets, crushed and sieved to 12/20 mesh. This catalyst may be made by the process described in US 2,900,423. The temperature of the catalyst bed was raised to 350°C and purged with nitrogen (50 seem, 8.3 x 10^"7 m³) for 60 minutes and then with hydrogen for 30 minutes. The temperature was then raised to 425⁰C while still purging with H₂ for 60 minutes. CFC-41-I Omca was then vaporized at

10 107⁰C and reacted with hydrogen over the above catalyst at conditions as indicated in Table 2. Analysis of the reaction products also indicated results as shown in Table 2.

TABLE 2

15 HFC-23 = trifluoromethane pentyne = octafluoro-2-pentyne pfp2 = perfluoro-2-pentene C1418 = octafluorocyclopentene 1215xc = 2-chloropentafluoropropene

20 C1427 = 1 -hydroperfluorocyclopentene 1326 = 2-hydro-3-chloro-hexafluoro-2-butene

41 -10 = 3,3-dichloroperfluoropeπtane

1429 = 2-hydroperfluoro-2-pentene

1419 = 3-chloroperfluoro-2-pentene

Example 3

Example 3 demonstrates the hydrogenation of octafluoro-2-pentyne with 1 % catalyst by weight.

Into a 1 .3 L Hastelloy^® reactor 10g of Lindlar catalyst is loaded. Then, octafluoro-2-pentyne 65Og (3.06 mole) is added to the reactor.

Hydrogen is then added slowly, by increments which do not exceed Δp=

50psi. A total of 3 moles H₂ is added to the reactor. Analysis of the product by gas chromatography indicates that a majority of octafluoro-2- pentyne is converted into CF₃CH=CHCF₂CF₃, with a minor amount of saturated CF₃CH₂CH₂CF₂CF₃.

Note that not all of the activities described above in the general description or the examples are required, that a portion of a specific activity may not be required, and that one or more further activities may be performed in addition to those described. Still further, the order in which activities are listed are not necessarily the order in which they are performed.

In the foregoing specification, the concepts have been described with reference to specific embodiments. However, one of ordinary skill in the art appreciates that various modifications and changes can be made without departing from the scope of the invention as set forth in the claims below. Accordingly, the specification and figures are to be regarded in an illustrative rather than a restrictive sense, and all such modifications are intended to be included within the scope of invention.

Benefits, other advantages, and solutions to problems have been described above with regard to specific embodiments. However, the benefits, advantages, solutions to problems, and any feature(s) that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as a critical, required, or essential feature of any or all the claims.

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

Claims

CLAIMSWhat is claimed is:

1 . A process comprising: reacting CF₃CF₂CCI₂CF₂CF₃ (CFC^I -I Omca) with hydrogen in the presence of a dehalogenation catalyst to produce

CF₃CF₂CCI=CFCF₃ (CFC-1419myx).

2. A process comprising: reacting CF₃CF₂CCI=CFCF₃ (CFC-1419myx) with hydrogen in the presence of a dehalogenation catalyst to produce

CF₃CF₂C=CCF₃ (octafluoro-2-pentyne).

3. The process of claim 1 , further comprising: reacting CF₃CF₂CCI=CFCF₃ (CFC-1419myx) with hydrogen in the presence of a dehalogenation catalyst to produce

CF₃CF₂C=CCF₃ (octafluoro-2-pentyne).

4. A process comprising: reacting CF₃CF₂CCI₂CF₂CF₃ (CFC-41 -10mca) with hydrogen in the presence of a dehalogenation catalyst to produce

CF₃CF₂C=CCF₃ (octafluoro-2-pentyne).

5. The process of claim 2, 3, or 4, further comprising: reacting CF₃CF₂C=CCF₃, in a pressure vessel, with an hydrogenation catalyst to produce CF₃CF₂CH=CHCF₃

(1 ,1 ,1 ,4,4,5,5,5-octafluoro-2-pentene).

6. The process of claim 5, wherein said hydrogenation catalyst comprises a Lindlar catalyst.

7. The process of claim 1 , wherein the CF₃CF₂CCI=CFCF₃ (CFC- 1419myx) is produced by an addition reaction of CF₂CI₂ (CFC- 12) and CF₂=CF₂ (tetrafluoroethylene) in the presence of a catalyst.

8. The process of claim 7, wherein the catalyst is an aluminum halide catalyst.