WO2005058489A1 - Compositions catalytiques selectives, leur elaboration et leur utilisation pour la production de 1,1,2-trichloropentafluoropropane - Google Patents

Compositions catalytiques selectives, leur elaboration et leur utilisation pour la production de 1,1,2-trichloropentafluoropropane Download PDF

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WO2005058489A1
WO2005058489A1 PCT/US2004/042157 US2004042157W WO2005058489A1 WO 2005058489 A1 WO2005058489 A1 WO 2005058489A1 US 2004042157 W US2004042157 W US 2004042157W WO 2005058489 A1 WO2005058489 A1 WO 2005058489A1
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cfc
reactor
surface area
bet surface
catalyst composition
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Allen Capron Sievert
Velliyur Nott Mallikarjuna Rao
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E.I. Dupont De Nemours And Company
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/16—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
    • B01J23/24—Chromium, molybdenum or tungsten
    • B01J23/26—Chromium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/08—Heat treatment
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G37/00—Compounds of chromium
    • C01G37/02—Oxides or hydrates thereof
    • C01G37/033—Chromium trioxide; Chromic acid
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C17/00—Preparation of halogenated hydrocarbons
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C17/00—Preparation of halogenated hydrocarbons
    • C07C17/093—Preparation of halogenated hydrocarbons by replacement by halogens
    • C07C17/10—Preparation of halogenated hydrocarbons by replacement by halogens of hydrogen atoms
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C17/00—Preparation of halogenated hydrocarbons
    • C07C17/093—Preparation of halogenated hydrocarbons by replacement by halogens
    • C07C17/20—Preparation of halogenated hydrocarbons by replacement by halogens of halogen atoms by other halogen atoms
    • C07C17/202—Preparation of halogenated hydrocarbons by replacement by halogens of halogen atoms by other halogen atoms two or more compounds being involved in the reaction
    • C07C17/206—Preparation of halogenated hydrocarbons by replacement by halogens of halogen atoms by other halogen atoms two or more compounds being involved in the reaction the other compound being HX
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C19/00—Acyclic saturated compounds containing halogen atoms
    • C07C19/08—Acyclic saturated compounds containing halogen atoms containing fluorine
    • C07C19/10—Acyclic saturated compounds containing halogen atoms containing fluorine and chlorine
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/60—Particles characterised by their size
    • C01P2004/62—Submicrometer sized, i.e. from 0.1-1 micrometer
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/60—Particles characterised by their size
    • C01P2004/64—Nanometer sized, i.e. from 1-100 nanometer
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/12—Surface area
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00—Technologies relating to chemical industry
    • Y02P20/50—Improvements relating to the production of bulk chemicals
    • Y02P20/582—Recycling of unreacted starting or intermediate materials

Definitions

  • This invention relates to chromium oxide catalysts, their preparation, and their use for preparing halogenated hydrocarbons.
  • 6,540,933 discloses that 1 ,2-dichloro- hexafluoropropane (CF3CCIFCCIF2 or CFC-216ba), or its azeotrope with HF, can be dechlorinated with hydrogen to afford HFP and that CFC- 216ba can be prepared by contacting 1 ,1 ,2-trichloropentafluoropropane (CF3CCIFCCI2F or CFC-215bb) with a mixture of HF and chlorine in the vapor phase in the presence of a catalyst.
  • CF3CCIFCCI2F or CFC-215bb 1 ,2-dichloro- hexafluoropropane
  • CFC- 216ba can be dechlorinated with hydrogen to afford HFP
  • CFC- 216ba can be prepared by contacting 1 ,1 ,2-trichloropentafluoropropane (CF3CCIFCCI2F or CFC-215bb) with a mixture
  • This invention provides a selective catalyst composition comprising Cr 2 O 3 having a BET surface area of from about 1 to about 7 m 2 /g.
  • This invention also provides a method for preparing said selective catalyst composition. The method comprises calcining ⁇ -chromium oxide having a BET surface area of at least 10 m 2 /g at a temperature of from about 1000°C to about 1200°C for a time sufficient to produce Cr 2 O 3 having a BET surface area of from about 1 to about 7 m 2 /g.
  • This invention also provides a selective catalyst composition prepared by treating a composition (e.g., the above-referenced selective catalyst composition) comprising Cr 2 O 3 having a BET surface area of from about 1 to about 7 m 2 /g with a fluorinating agent.
  • a composition e.g., the above-referenced selective catalyst composition
  • Cr 2 O 3 having a BET surface area of from about 1 to about 7 m 2 /g
  • This invention also provides a process for the production of 1 ,1 ,2- trichloropentafluoropropane (CFC-215bb).
  • a fluorinating agent e.g., anhydrous hydrogen fluoride
  • CFC-215bb CF 3 CCIFCCI 2 F
  • CFC-215aa CF 3 CCI 2 CCIF 2
  • selective catalyst compositions comprising Cr 2 O 3 having a BET surface area of from about 1 to about 7 m 2 /g in accordance with this invention provides a means to obtain a high relative yield of CFC- 215bb compared to CFC-215aa.
  • CFC-215bb is the desired isomer (e.g., as a precursor compound in the manufacture of HFP).
  • CF3CC CCI2 CFC-1213xa
  • the reaction of HF and CI2 with CX3CC CCIX is carried out in the vapor phase in a heated tubular reactor.
  • a number of reactor configurations are possible, including vertical and horizontal orientation of the reactor and different modes of contacting the halopropene starting material(s) with HF and chlorine.
  • the HF and chlorine are substantially anhydrous.
  • the halopropene starting material(s) are fed to the reactor containing the chlorofluorination catalyst.
  • the halopropene starting material(s) may be initially vaporized and fed to the first reaction zone as gas(es).
  • the halopropene starting material(s) may be contacted with HF in a pre-reactor.
  • the pre-reactor may be empty (i.e., unpacked), but is preferably filled with a suitable packing such as MonelTM or HastelloyTM nickel alloy turnings or wool, or other material inert to HCI and HF which allows efficient mixing of CX3CC CCIX and HF vapor.
  • Suitable temperatures for the pre-reactor are within the range of from about 80°C to about 250°C, preferably from about 100°C to about 20O°C. Under these conditions, for example, hexachloropropene may be converted to a mixture containing predominantly CFC-1213xa.
  • the starting material feed rate is ordinarily determined by the length and diameter of the reactor, the temperature, and the degree of fluorination desired within the pre-reactor.
  • CF3CC CCIF represents a higher degree of fluorination than CCIF2CC CCI2
  • CF3CCI2CF3 represents a higher degree of fluorination than CCIF2CCI2CF3.
  • the molar ratio of HF fed to the pre-reactor, or otherwise to the reaction zone, to halopropene starting material is typically from about stoichiometric to about 50:1.
  • the stoichiometric ratio depends on the average degree of fluorination of the halopropene starting material(s) and is typically based on formation of C3CI3F5. For example, if the halopropene is HCP, the stoichiometric ratio of HF to HCP is 5:1 ; if the halopropene is CFC-1213xa, the stoichiometric ratio of HF to CFC-1213xa is 2:1.
  • the molar ratio of HF to halopropene starting material is from about twice the stoichiometric ratio (based on formation of C3CI3F5) to about 30:1. Higher ratios of HF to halopropene are not particularly beneficial.
  • halopropene starting materials are contacted with HF in a pre- reactor, the effluent from the pre-reactor is then contacted with chlorine in the presence of a chlorofluorination catalyst.
  • the halopropene starting material(s) may be contacted with CI2 and HF in a pre-reactor.
  • Suitable temperatures for the pre-reactor in this embodiment of the invention are within the range of from about 80°C to about 250°C, preferably from about 100°C to about 200°C. Higher temperatures result in greater conversion of the halopropene(s) entering the reactor to saturated products and greater degrees of halogenation and fluorination in the pre-reactor products.
  • degree of halogenation means the extent to which hydrogen substituents in a halocarbon have been replaced by halogen and the extent to which carbon-carbon double bonds have been saturated with halogen.
  • CF3CCI2CCIF2 has a higher degree of halogenation than CF3CC CCI2.
  • CF3CCI2CCIF2 has a higher degree of halogenation than CF3CHCICCIF2.
  • the molar ratio of Cb_ to halopropene starting material(s) is typically from about 1 :1 to about 10:1 , and is preferably from about 1 :1 to about 5:1 . Feeding Cb_ at less than a 1 :1 ratio will result in the presence of relatively large amounts of unsaturated materials and hydrogen-containing side products in the reactor effluent.
  • the halopropene starting materials are vaporized, preferably in the presence of HF, and contacted with HF and CI2 in a pre-reactor and then contacted with the chlorofluorination catalyst.
  • Suitable temperatures for catalytic chlorofluorination of halopropene starting material and/or their products formed in the pre- reactor are within the range of from about 200°C to about 450°C, preferably from about 250°C to about 400°C, depending on the desired conversion of the starting material and the activity of the catalyst. Reactor temperatures greater than about 350°C may result in products having a degree of fluorination greater than five.
  • Suitable reactor pressures for vapor phase embodiments of this invention may be in the range of from about 1 to about 30 atmospheres. Reactor pressures of about 5 atmospheres to about 20 atmospheres may be advantageously employed to facilitate separation of HCI from other reaction products after the chlorofluorination.
  • the chlorofluorination catalysts which are used in the process of the present invention are compositions comprising Cr2 ⁇ 3 (chromium oxide) having a BET surface area of between about 1 m 2 /g and about 7 m 2 /g, or compositions obtained by treatment of said compositions comprising Cr2 ⁇ 3 with a fluorinating agent.
  • BET surface area means a surface area measured by the well-known BET method, described for example in Journal of the American Chemical Society, Vol. 60, page 309 (1938).
  • compositions comprising Cr2 ⁇ 3 having a BET surface area of between about 1 m 2 /g and about 5 m 2 /g or compositions obtained by treatment of said compositions comprising Cr2 ⁇ 3 with a fluorinating agent.
  • these chlorofluorination catalysts may be prepared by calcination of ⁇ -chromium oxide compositions having a BET surface area of at least 10 m 2 /g at a temperature of from about 1000°C to about 1200°C at a temperature of from about 1000°C to about 1200°C (followed by fluorination with a fluorinating agent, if desired).
  • chlorofluorination catalysts prepared by calcination of ⁇ -chromium oxide compositions having a BET surface area of at least 20 m 2 /g.
  • chromium oxide compositions prepared by pyrolyzing ammonium dichromate preferably in accordance with the teaching of U.S. Patent No.
  • chromium oxide compositions wherein the particle size of the crystallites are relatively uniform, with at least about 80% of the crystallites having a particle size close to a particular value between about 150 nm and about 600 nm.
  • the average particle size of chromium oxide crystallites normally depends on the calcination temperature as exemplified in the Examples below.
  • the selective catalyst compositions of the present invention may be pressed into various shapes such as pellets for use in packing reactors. They may also be used in powder form.
  • Porous structures of the selective catalyst compositions can be obtained for example by co-mixing (1) particles of the Cr2 ⁇ 3 obtained by calcination with (2) a powdered organic polymer (e.g., polyethylene), pressing the mixture into a desired shape, and subjecting the shaped mixture to thermolysis (e.g. at a temperature of from about 400°C to about 600°C) in the presence of air to remove the organic polymer component. Under certain conditions the use of such porous structures can reduce the pressure drop during catalyst use.
  • a powdered organic polymer e.g., polyethylene
  • Composite structures can be obtained, for example, by coating particles of the Cr2 ⁇ 3 obtained by calcination onto an inert (e.g., silicon carbide) support. Coating can be accomplished by well-known techniques (e.g., slurry spray-coating in a manner similar to that used for automotive paints). Typically, the selective catalyst compositions will be pre-treated with a fluorinating agent prior to use as catalysts for changing the fluorine content of halogenated carbon compounds.
  • an inert e.g., silicon carbide
  • Coating can be accomplished by well-known techniques (e.g., slurry spray-coating in a manner similar to that used for automotive paints).
  • the selective catalyst compositions will be pre-treated with a fluorinating agent prior to use as catalysts for changing the fluorine content of halogenated carbon compounds.
  • this fluorinating agent is HF though other materials may be used such as sulfur tetrafluoride, carbonyl fluoride, boron trifluoride, and fluorinated carbon compounds such as trichlorofluoromethane, dichlorodifluoromethane, chlorodifluoromethane, trifluoromethane, or 1 ,1 ,2-trichlorotrifluoroethane.
  • This pretreatment can be accomplished, for example, by placing the catalyst in a suitable container which can be the reactor to be used to perform the process in the instant invention, and thereafter, passing HF over the catalyst so as to partially saturate the catalyst with HF.
  • CFC-215bb CF 3 CCIFCCI 2 F
  • CFC-215aa and CFC- 215bb can be used together for the manufacture of HFP and optionally other useful products (e.g., CF3CH2CF3). Accordingly, a useful process for the preparation of both CFC-215aa and CFC-215bb is provided.
  • catalysts comprising chromium oxide compositions which have been calcined as disclosed herein to provide BET surface areas of between about 1 m 2 /g and about 5 m 2 /g, or fluorinated forms thereof, can actually result in reverse selectivity in the formation of these trichloropentafluoropropanes by chlorofluorination of CFC-1213xa.
  • a chromium oxide composition having a BET surface area of between about 1 m 2 /g and about 5 m 2 /g can result in the formation of more CFC-215bb than CFC- 215aa under conditions where a chromium oxide composition having a BET surface area of greater than about 5 m 2 /g results in the formation of more CFC-215aa than CFC-215bb.
  • Halopropane by-products that have a higher degree of fluorination than CFC-215bb and CFC-215aa that may be produced include CF3CCI2CF3 (CFC-216aa), CF 3 CCIFCCIF 2 (CFC-216ba), CF 3 CF 2 CCI 2 F (CFC-216cb), CF3CCIFCF3 (CFC-217ba), and CF3CHCICF3 (HCFC- 226da).
  • Halopropane by-products that may be formed which have lower degrees of fluorination than CFC-215bb and CFC-215aa include CF 3 CCI 2 CCI 2 F (HCFC-214ab).
  • the effluent from reaction zone comprising CF3CCI2CCIF2 (CFC-215aa) and CF 3 CCIFCCI 2 F (CFC-215bb), and optionally HF, is separated from lower boiling components comprising HCI, CI2, HF, over-fluorinated products comprising C3CIF7 and C3CI2F6 isomers, the under-halogenated components comprising C3CIF5 and C3CI2F4 isomers, and the under-fluorinated components comprising C3CI4F4 isomers and CFC-1213xa.
  • the reactor effluent from the reaction zone may be delivered to a distillation column in which HCI, Cb_ and any HCI azeotropes are removed from the top of column while the higher boiling components are removed at the bottom of the column (see e.g., Figure 1 , distillation column (300) as further described below).
  • the products recovered at the bottom of the first distillation column are then delivered to a second distillation column in which HF, CF3CCI2CF3 (CFC- 216aa), CF3CCIFCCIF2 (CFC-216ba), CF3CF2CCI2F (CFC-216cb), CF3CCIFCF3 (CFC-217ba), CF3CF2CCIF2 (CFC-217ca), CF3CC CF2 (CFC-1215xc), and CF3CHCICF3 (HCFC-226da) and their HF azeotropes are recovered at the top of the column and CFC-215aa and CFC-215bb, and any remaining HF and the higher boiling components are removed from the bottom of the column (see e.g., Figure 1 , distillation column (400) as further described below).
  • the products recovered from the bottom of the second distillation column may then be delivered to further distillation columns to separate the under-fluorinated by-products and intermediates and to isolate CFC-215aa and CFC-215bb (see e.g., Figure 1 , distillation column (500) as further described below).
  • the resulting mixture of HF and halopropanes and halopropenes may be delivered to a decanter controlled at a suitable temperature to permit separation of a liquid HF-rich phase and a liquid organic-rich phase.
  • the organic-rich phase may then be distilled to isolate the CFC- 215aa and CFC-215bb.
  • the HF-rich phase may then be recycled to the reaction zone, optionally after removal of any organic components by distillation.
  • the decantation step may be used at other points in the CFC- 215aa/CFC-215bb separation scheme where HF is present.
  • said underfluorinated and underhalogenated components e.g., CFC-214ab, CFC-1212xb, and CFC-1213xa
  • CFC-214ab, CFC-1212xb, and CFC-1213xa are returned to the reaction zone.
  • the lower boiling by-products and over fluorinated products comprising CF3CCI2CF3 (CFC- 216aa), CF3CCIFCCIF2 (CFC-216ba), CF3CF2CCI2F (CFC-216cb), CF3CCIFCF3 (CFC-217ba), CF3CF2CCIF2 (CFC-217ca), CF3CC CF2 (CFC-1215xc), and CF3CHCICF3 (HCFC-226da), their HF azeotropes and HF, if present, are further reacted with HF, or if HCFC-226da is present, HF and CI2, to give CF3CCIFCF3 (CFC-217ba) which in turn may be converted to hexafluoropropene (HFP) as disclosed in U.S.
  • HFP hexafluoropropene
  • the HCFC-226da, CFC-216aa, CFC-216ba, CFC-217ba, and by-products are further reacted with hydrogen (H2) to give 1 ,1 ,1 ,3,3,3-hexafluoropropane (HFC-236fa), 1 ,1 ,1 ,2,3,3-hexafluoropropane (HFC-236ea), and 1 ,1 ,1 ,2,3,3,3- heptafluoropropane (HFC-227ea) (see e.g., U.S. Patent No. 6,291 ,729 and U. S.
  • This invention also provides a process for the manufacture of hexafluoropropene (HFP).
  • the process comprises (a) reacting hydrogen fluoride (HF), chlorine (CI2), and at least one halopropene of the formula CX3CC CCIX, wherein each X is independently selected from the group consisting of F and Cl, to produce a product comprising CF3CCIFCCI2F and CF3CCI2CCIF2, wherein said CF3CCIFCCI2F and CF3CCI2CCIF2 are produced in the presence of a catalyst composition selected from the group consisting of (i) catalyst compositions comprising Cr 2 O 3 having a BET surface area of from about 1 to about 7 m 2 /g, and (ii) catalyst compositions of (i) which have been treated with a fluorinating agent (e.g., anhydrous hydrogen fluoride); (b) recovering CF3CCIFCCI2F and CF3CCI2CC
  • a fluorinating agent e
  • the CF3CH2CF3 produced in (e) may also be recovered. Accordingly, a process for the manufacture of both HFP and HFC-236fa is also provided by this invention.
  • the step (a) chlorofluorination is accomplished in the manner described above in connection with the process of this invention for producing CFC-215bb.
  • step (b) CFC-215aa and CFC-215bb (and optionally HF and/or
  • CI2) from step (a) are typically separated from the low-boiling components of the step (a) effluent (which typically comprise HCI, CI2, HF and over- fluorinated products) and under-fluorinated components of the step (a) effluent.
  • the under-fluorinated components may be recycled to the step (a) reaction zone(s).
  • step (c) of the process the CFC-215bb and CFC-215aa are reacted with additional HF, and optionally chlorine, in a second reaction zone to produce a product mixture comprising CF3CCIFCCIF2 (CFC- 216ba) and CF3CCI2CF3 (CFC-216aa).
  • this invention provides a process for the preparation of mixtures of CF3CCIFCCIF2 (CFC-216ba) and CF3CCI2CF3 (CFC-216aa) from readily available starting materials.
  • the reaction of HF, and optionally CI2, with CFC-215bb and CFC-215aa in step (c) is carried out in the vapor phase in a heated tubular reactor.
  • a number of reactor configurations are possible including horizontal or vertical orientation of the reactor and different modes of contacting the trichloropentafluoropropane starting materials (i.e., CFC-215bb and CFC-215aa) with HF and chlorine.
  • the HF and chlorine are substantially anhydrous.
  • the trichloropentafluoropropane starting materials are fed to the reactor containing the fluorination catalyst.
  • the starting materials may be initially vaporized and fed to the reactor as gas(es).
  • the molar ratio of HF to trichloropentafluoropropanes fed to the reaction zone of step (c) is typically from about 5:1 to about 50:1.
  • the ratio of HF to trichloropentafluoropropanes is from about 5:1 to about 30:1. Higher ratios of HF to trichloropentafluoropropanes are not particularly beneficial; lower ratios result in reduced yields of dichlorohexafluoropropanes.
  • Chlorine (CI2) may be co-fed to the reaction zone of step (c).
  • the molar ratio of trichloropentafluoropropanes starting materials to chlorine is typically from about 1 :1 to about 4:1.
  • Suitable temperatures in the reaction zone of step (c) are within the range of from about 200°C to not more than 400°C, preferably from about 250°C to about 35O°C. Higher temperatures result in greater conversion of the trichloropentafluoropropanes starting materials, but also result in formation of overfluorinated products such as CF3CCIFCF3 and contribute to reduced catalyst life. Temperatures lower than about 250°C result in low yields of CFC-216ba and CFC-216aa.
  • Suitable reactor pressures for step (c) may be in the range of from about 1 to about 30 atmospheres. Reactor pressures of about 5 atmospheres to about 20 atmospheres may be advantageously employed to facilitate separation of HCI from other reaction products. While various known fluorination catalysts may be employed in step
  • preferred vapor phase fluorination catalysts for step (c) comprise trivalent chromium.
  • the catalyst compositions used in step (a) as well as the catalyst compositions used in step (c) will each be pre- treated with a fluorinating agent prior to their use as catalysts.
  • Compounds that are produced in the fluorination process of step (c) include the halopropanes CF3CCIFCCIF2 (CFC-216ba) and CF3CCI2CF3 (CFC-216aa).
  • Halopropane by-products that have a higher degree of fluorination than CFC-216ba and CFC-216aa that may be produced in step (c) include CF3CCIFCF3 (CFC-217ba), CF3CF2CCIF2 (FC-217ca) and CF3CF2CF3 (FC-218).
  • step (d) CFC-216ba and CFC-216aa, (and optionally HF) from step (c) are typically separated from the low boiling components of the step (c) effluent (which typically comprise HCI, CI2, HF, and over- fluorinated products such as CF3CCIFCF3) and the under-fluorinated components of the step (c) effluent.
  • the under-fluorinated components may be returned to the step (a) and/or the step (c) reaction zone(s).
  • the reactor effluent from step (c) is delivered to a distillation column in which HCI, Cb_ and any HCI azeotropes are removed from the top of the column while the higher boiling components are removed from the bottom of the column.
  • the products removed from the bottom of the first distillation column are then delivered to a second distillation column in which HF and any products having a higher degree of fluorination than CFC-216ba abd CFC-216aa are removed at the top of the second distillation column and remaining HF and organic products, comprising CF3CCIFCCIF2 and CF3CCI2CF3, are removed at the bottom of the distillation column.
  • the products removed from the bottom of the second distillation column may be delivered to further distillation columns or may be delivered to a decanter controlled at a suitable temperature to permit separation of an organic-rich phase and an HF-rich phase.
  • the HF-rich phase may be distilled to obtain HF which is then recycled to step (a).
  • the organic-rich phase may then be delivered to step (e).
  • CFC-217ba may be recovered as an over-fluorinated by-product in step (d) and may be converted to hexafluoropropene (HFP) as disclosed in U.S. Patent Nos. 5,068,472 and 5,057,634.
  • step (e) of the process CFC-216ba and CFC-216aa are contacted with hydrogen (H2) in a second reaction zone.
  • the CFC- 216ba and CFC-216aa may be fed to the reactor zone at least in part as their azeotropes with HF.
  • a mixture comprising CF3CCIFCCIF2 and CF3CCI2CF3 is delivered in the vapor phase, along with hydrogen, to a reactor fabricated from nickel, iron, titanium, or their alloys, as described in U. S. Patent No. 6,540,933; the teachings of this disclosure are incorporated herein by reference.
  • a reaction vessel of these materials e.g., a metal tube
  • metal in suitable form may also be used.
  • alloys it is meant a nickel alloy containing from 1 to 99.9% (by weight) nickel, an iron alloy containing 0.2 to 99.8% (by weight) iron, and a titanium alloy containing 72-99.8% (by weight) titanium.
  • an empty (unpacked) reaction vessel made of nickel or alloys of nickel such as those containing 40% to 80% nickel, e.g., Inconel TM 600 nickel alloy, HastelloyTM C617 nickel alloy, or HastelloyTM C276 nickel alloy.
  • the metal or metal alloys When used for packing, the metal or metal alloys may be particles or formed shapes such as perforated plates, rings, wire, screen, chips, pipe, shot, gauze, or wool.
  • the temperature of the reaction in this embodiment of step (e) can be between about 350°C to about 600°C, and is preferably at least about 450°C.
  • the molar ratio of hydrogen to the CFC-216ba/CFC-216aa mixture fed to the reaction zone should be in the range of about 0.1 mole H2 per mole of CFC-216 isomer to about 60 moles of H2 per mole of CFC-216 isomer, more preferably from about 0.4 to 10 moles of H2 per mole of CFC-216 isomer.
  • the contacting of hydrogen with the mixture of CFC- 216ba and CFC-216aa, and optionally HF, is carried out in the presence of a hydrogenation catalyst.
  • said mixture is delivered in the vapor phase, along with hydrogen, to the reaction zone containing a hydrogenation catalyst.
  • Hydrogenation catalysts suitable for use in this embodiment include catalysts comprising at least one metal selected from the group consisting of rhenium, iron, ruthenium, osmium, cobalt, rhodium, iridium, nickel, palladium, and platinum.
  • Said catalytic metal component is typically supported on a carrier such as carbon or graphite or a metal oxide, fluorinated metal oxide, or metal fluoride where the carrier metal is selected from the group consisting of magnesium, aluminum, titanium, vanadium, chromium, iron, and lanthanum.
  • a carrier such as carbon or graphite or a metal oxide, fluorinated metal oxide, or metal fluoride where the carrier metal is selected from the group consisting of magnesium, aluminum, titanium, vanadium, chromium, iron, and lanthanum.
  • the preferred catalysts are those containing ruthenium, rhenium, or their mixtures (see e.g., U.S. Patent No. 6,127,585).
  • the desired products are HFC-236ea and HFC- 236fa
  • the preferred catalysts are those containing palladium (see e.g., U.S. Patent No. 6,291 ,729 or U.S.
  • the supported metal catalysts may be prepared by conventional methods known in the art such as by impregnation of the carrier with a soluble salt of the catalytic metal (e.g., palladium chloride or rhodium nitrate) as described by Satterfield on page 95 of'Heterogenous Catalysis in Industrial Practice, 2 nd edition (McGraw-Hill, New York, 1991).
  • the concentration of the catalytic metal(s) on the support is typically in the range of about 0.1% by weight of the catalyst to about 5% by weight.
  • Suitable temperatures for the reaction zone containing said hydrogenation catalyst are in the range of from about 110°C to about 40O°C, preferably from about 125°C to about 350°C.
  • the amount of hydrogen (H2) fed to the reaction zone containing said hydrogenation catalyst is typically from about 1 mole of H2 per mole of dichlorohexafluoropropane to about 20 moles of H2 per mole of dichlorohexafluoropropane, preferably from about 2 moles of H2 per mole of dichlorohexafluoropropane to about 10 moles of H2 per mole of dichlorohexafluoropropane.
  • the pressure used in the step (e) reaction zone is not critical and may be in the range of from about 1 to about 30 atmospheres. A pressure of about 20 atmospheres may be advantageously employed to facilitate separation of HCI from other reaction products.
  • small amounts of CF3CF2CH2F (HFC-236cb), CF3CC CF2 (CFC-1215xc), and partially chlorinated by-products such as C 3 HCIF 6 isomers including CF3CHCICF3 (HCFC-226da), CF3CCIFCHF3 (HCFC-226ba), CF 3 CHFCCIF 2 (HCFC-226ea), may be formed.
  • step (f) the HFP recovered.
  • HFC-236fa and/or HFC- 236ea (a hydrogenation product of HFP) may also be recovered.
  • the partially chlorinated by-products, including any unconverted CFC-216ba and CFC-216aa, may be recovered and returned to steps (a), (c), or (e).
  • Figure 1 is illustrative of one method of practicing this invention.
  • a feed mixture comprising HF, Cl 2 , and at least one halopropene of the formula CX3CC CCIX (wherein each X is independently selected from the group consisting of F and Cl) is passed through line (110) into pre-reactor (100).
  • the reactor effluent from pre-reactor (100) is passed through line (120) into line (710) where it is combined with the effluent from fluorination reactor (700) described below and line (510), the column bottoms from distillation column (500) described below.
  • the combination of lines (120), (510), and (710) is directed to reactor (200) which is preferably maintained at a temperature within the range of about 200°C to about 450°C.
  • Reactor (200) contains a chlorofluorination catalyst composition selected from the group consisting of (i) catalyst compositions comprising Cr 2 O 3 having a BET surface area of from about 1 to about 7 m 2 /g, and (ii) catalyst compositions of (i) which have been treated with a fluorinating agent. Additional HF may be co-fed to reactor (200) via line (230) if desired.
  • the effluent from the chlorofluorination reactor (200), comprising HF, HCI, unreacted Cl 2 , CFC-215bb, CFC-215aa, CFC-216ba, CFC- 216aa, CFC-217ba, HCFC-226da, CFC-1215xc, and CFC-214ab, is directed through line (210) to distillation column (300).
  • HCI and Cl 2 are removed through line (320) and the remaining components of the reactor (200) effluent are directed through line (310) into a second distillation column (400).
  • CFC-1215xc are removed from the top of column (400) through line (410) and directed to distillation column (600). Lower boiling components are removed from the top distillation column (600) by line (610).
  • CFC-216ba, CFC-216aa are removed from the bottom of distillation column (600) via line (620) and sent to reactor (800) where they are combined with hydrogen which is fed to reactor (800) through line (810).
  • Reactor (800) is typically maintained at a temperature of about 350°C to about 600°C.
  • the product comprising hexafluoropropene and HFC-236fa leaves reactor (800) through line (820) and is directed to product recovery units (not shown).
  • Materials taken from the bottom of distillation column (400) through line (420) comprise CFC-215bb, CFC-215aa, and higher boiling components.
  • This stream is sent to distillation column (500) where the CFC-215bb and CFC-215aa are collected at the top of the column at line (520). Higher boiling materials are collected at the bottom of the column and sent back to reactor (200) via line (510).
  • the stream in line (520) containing CFC-215bb and CFC-215aa is directed to reactor (700) where it is combined with HF added through line (720).
  • Reactor (700) contains a fluorination catalyst and is typically maintained at a temperature of from about 200°C to about 400°C.
  • the effluent from reactor (700) is directed to reactor (200) through line (710).
  • the effluent from reactor (700) contains CFC-216ba and CFC- 216aa, and these compounds typically pass through reactor (200) without significant further reaction and are directed on to the distillation columns.
  • the reactor, distillation columns, and their associated feed lines, effluent lines, and associated units used in applying the processes of this invention should be constructed of materials resistant to hydrogen fluoride and hydrogen chloride.
  • Typical materials of construction include stainless steels, in particular of the austenitic type, the well-known high nickel alloys, such as MonefTM nickel-copper alloys, HastelloyTM nickel-based alloys and, InconelT nickel-chromium alloys, and copper-clad steel.
  • the following specific embodiments are to be construed as merely illustrative, and do not constrain the remainder of the disclosure in any way whatsoever.
  • 214ab is CF3CCI2CCI2F 215aa is CF3CCI2CCIF2
  • 215bb is CCI 2 FCCIFCF 3 216aa is CF3CCI2CF3
  • 216ba is CCIF2CCIFCF3
  • 216cb is CCI 2 FCF 2 CF 3
  • 217ba is CF3CCIFCF3 217ca is CF3CF2CCIF2 226da is CF3CHCICF3 1213xa is CF3CC CCI2
  • Chromium Oxide Compositions The chromium oxide compositions used in Examples 1-14 were prepared by calcining ⁇ -chromium oxide prepared by pyrolysis of ammonium dichromate (see U.S. Patent No. 5,036,036) at 500°C, 700°C, 900°C, 1000°C, 1100°C, 1200°C and 1300°C for ten hours.
  • the surface areas of the chromium oxide compositions resulting from the calcinations were determined by the BET method to be 30.2 m 2 /g, 18.2 m 2 /g, 8.2 m 2 /g, 4.6 m 2 /g, 2.5 m 2 /g, 1.7 m 2 /g and 0.3 m 2 /g, respectively.
  • Dinitrogen adsorption/desorption measurements were performed using a Micromeritics ASAP model 2400/2405 porosimeter. Samples were degassed at 150°C overnight prior to data collection. Surface area measurements utilized a five-point adsorption isotherm collected over 0.05 to O.20 p/pO and analyzed via the BET method (see S. Brunauer, P. H.
  • the surface area of the chromium oxide prepared by pyrolysis of ammonium dichromate that was used for the calcinations was about 42.1 m 2 /g. Images of the crystallites in the chromium oxide compositions resulting from calcination at 500°C, 1000°C, 1100°C and 1200°C were obtained using transmission electron microscopy (TEM).
  • TEM transmission electron microscopy
  • a weighed quantity of pelletized chromium oxide was placed in a 5/8" (1.58 cm) diameter InconelTM nickel alloy reactor tube heated in a fluidized sand bath. The tube was heated from 50°C to 175°C in a flow of nitrogen (50 cc/min; 8.3(10) "7 m 3 /sec) over the course of about one hour. HF was then admitted to the reactor at a flow rate of 50 cc/min (8.3(10)" 7 m 3 /sec).
  • CFC-1213xa was fed from a pump to a vaporizer maintained at about 118°C.
  • the CFC-1213xa vapor was combined with the appropriate molar ratios of HF and CI2 in a 0.5 inch (1.27 cm) diameter MonelTM nickel alloy tube packed with MonelTM turnings.
  • the mixture of reactants then entered the reactor. All reactions were conducted at a nominal pressure of one atmosphere. Analytical data is given in units of GC area %. In all cases the molar ratio of HF to CFC- 1213xa to Cl 2 was 20 : 1 : 4 and contact time was five seconds.
  • the CFC-215bb vapor was combined with the appropriate molar ratio of HF in a 0.5 inch (1.27 cm) diameter MonelTM nickel alloy tube packed with MonelTM turnings. The mixture of reactants then entered the reactor. All reactions were conducted at a nominal pressure of one atmosphere. Analytical data is given in units of GC area %. In all cases the molar ratio of HF to CFC-215bb was 20 : 1 and contact time was five seconds.

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Abstract

L'invention concerne une composition catalytique sélective qui comprend du Cr2O3 à surface spécifique BET comprise entre environ 1 et environ 7 m2/g, et un procédé d'élaboration : calcination d'oxyde d'alpha-chrome à BET d'au moins 10 m2/g à une température allant de 1 000° C à environ 1 200° C pendant une durée suffisante pour produire du Cr2O3 à BET comprise entre environ 1 et environ 7 m2/g. On décrit aussi une composition catalytique sélective élaborée par traitement d'une composition comprenant du Cr2O3 à BET comprise entre environ 1 et environ 7 m2/g avec un agent de fluoration. On décrit encore un procédé d'élaboration de1,1,2-trichloropentafluoropropane : réaction entre fluorure d'hydrogène, chlore, et au moins un halopropène de formule CX3CCI=CCIX (chaque X est indépendamment F ou CI) pour donner un produit qui comprend CF3CCIFCCI2F, lequel est obtenu en présence d'une composition catalytique renfermant du Cr2O3 à BET comprise entre environ 1 et environ 7 m2/g ou d'une composition catalytique élaborée par traitement avec un agent de fluoration.
PCT/US2004/042157 2003-12-16 2004-12-15 Compositions catalytiques selectives, leur elaboration et leur utilisation pour la production de 1,1,2-trichloropentafluoropropane WO2005058489A1 (fr)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008030444A2 (fr) * 2006-09-05 2008-03-13 E. I. Du Pont De Nemours And Company Procédé de fabrication du 1,2,3,3,3-pentafluoropropène et compositions azéotropes apparentées
WO2008060612A2 (fr) * 2006-11-15 2008-05-22 E. I. Du Pont De Nemours And Company Procédés de production de pentafluoropropènes et d'azéotropes comprenant hf et de certains halopropènes représentés par la formule c3ci2f4, c3cif5, ou c3hf5

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US5036036A (en) * 1989-06-13 1991-07-30 E. I. Du Pont De Nemours And Company Chromium oxide catalyst composition
US5053580A (en) * 1987-11-17 1991-10-01 Veba Oel Aktiengesellschaft Metal oxide powders, their mixtures, metal mixed oxide powders, their mixtures and their use in catalytic dehydrogenation of hydrocarbons
US5306845A (en) * 1992-05-12 1994-04-26 Mitsubishi Kasei Corporation Method for producing an aldehyde
US5623092A (en) * 1991-03-07 1997-04-22 Imperial Chemical Industries Plc Fluorination catalyst and process

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5053580A (en) * 1987-11-17 1991-10-01 Veba Oel Aktiengesellschaft Metal oxide powders, their mixtures, metal mixed oxide powders, their mixtures and their use in catalytic dehydrogenation of hydrocarbons
US5036036A (en) * 1989-06-13 1991-07-30 E. I. Du Pont De Nemours And Company Chromium oxide catalyst composition
US5623092A (en) * 1991-03-07 1997-04-22 Imperial Chemical Industries Plc Fluorination catalyst and process
US5306845A (en) * 1992-05-12 1994-04-26 Mitsubishi Kasei Corporation Method for producing an aldehyde

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008030444A2 (fr) * 2006-09-05 2008-03-13 E. I. Du Pont De Nemours And Company Procédé de fabrication du 1,2,3,3,3-pentafluoropropène et compositions azéotropes apparentées
WO2008030444A3 (fr) * 2006-09-05 2008-05-29 Du Pont Procédé de fabrication du 1,2,3,3,3-pentafluoropropène et compositions azéotropes apparentées
US7928271B2 (en) 2006-09-05 2011-04-19 E.I. Du Pont De Nemours And Company Process for producing 1,2,3,3,3-pentafluoropropene and related azeotropic compositions
US20110163253A1 (en) * 2006-09-05 2011-07-07 E. I. Du Pont De Nemours And Company Processes for producing 1,2,3,3,3-pentafluoropropene
WO2008060612A2 (fr) * 2006-11-15 2008-05-22 E. I. Du Pont De Nemours And Company Procédés de production de pentafluoropropènes et d'azéotropes comprenant hf et de certains halopropènes représentés par la formule c3ci2f4, c3cif5, ou c3hf5
WO2008060612A3 (fr) * 2006-11-15 2008-11-13 Du Pont Procédés de production de pentafluoropropènes et d'azéotropes comprenant hf et de certains halopropènes représentés par la formule c3ci2f4, c3cif5, ou c3hf5
US8058489B2 (en) 2006-11-15 2011-11-15 E.I. Du Pont De Nemours And Company Processes for producing pentafluoropropenes and azeotropes comprising HF and certain halopropenes of the formula C3Cl2F4, C3ClF5, or C3HF5

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