Classifications

• • 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
• • 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
  • 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
  • C07C17/21—Preparation of halogenated hydrocarbons by replacement by halogens of halogen atoms by other halogen atoms with simultaneous increase of the number of halogen atoms

Definitions

• the present invention relates to a process for the production of 1,1,1,2,3,3,3-heptafluoropropane from chlorocarbon feedstocks, particularly from certain 2-hydro-2-chloropropanes or certain 2-chloropropenes as hereinafter defined, more particularly in a 2-reaction stage process.
• Hydrofluorocarbons are widely used as replacements for chlorofiuorocarbon compounds. Such uses include use in medical applications, for example as an aerosol propellant, use as a fire suppressant, use in refrigeration applications and in other applications.
• 1,1,1,2,3,3,3-heptafluoropropane which will be referred to hereinafter for convenience as HFC 227ea, has zero ozone depletion potential and is particularly beneficial in medical propellant applications in the light of its combination of properties including low toxicity, non-flammability, solvent properties and boiling point.
• HFC 227ea by the hydrofluorination of hexafluoropropene, hereinafter referred to for convenience as HFP, using hydrogen fluoride as the hydrofluorination agent, optionally in the presence of a catalyst, in the liquid phase or vapour phase.
• HFC 227ea A major disadvantage in the production of HFC 227ea from HFP is the high cost ofHFP.
• HCFC 226da 2-Chloro-l,l,l,3,3,3-hexafluoropropane, hereinafter referred to for convenience as HCFC 226da, is an intermediate in the process according to the present invention and we have found surprisingly that conversion thereof into HFC 227ea is equilibrium limited. Accordingly, removal of at least a major part of the HCl generated in the first step of the process according to the present invention facilitates conversion of HCFC
• HCFC 226da is the major product of Step (A) of the process according to the present invention.
• Step (A) of the process according to the present invention may be carried out in the liquid or vapour phase.
• Step (A) is carried out in the liquid phase it is carried out in the presence of a suitable catalyst, at a temperature within the range 50-150°C, at pressures up to 30 bar, using a molar ratio of HF: organic feed at least as required by stoichiometry to fluorinate the organic starting material to HCFC 226da.
• Step (A) is carried out in the vapour phase it is carried out in the presence of a suitable catalyst, at a temperature within the range 150-450°C, using a molar ratio of HF:organic feed at least as required by stoichiometry to fluorinate the organic starting material to HCFC 226da, preferably an excess of HF is used.
• a suitable catalyst at a temperature within the range 150-450°C, using a molar ratio of HF:organic feed at least as required by stoichiometry to fluorinate the organic starting material to HCFC 226da, preferably an excess of HF is used.
• the starting material is HHCP
• a 6: 1 molar ratio of HF:HHCP is required, preferably the molar ratio of HF:HHCP is in the range 6:1-100:1, more preferably in the range 6:1- 50: 1.
• the reaction can be carried out at within a wide range of pressures, from subatmospheric to superatmospheric, preferably at a pressure within the range 1-50 bar.
• suitable fluorination catalysts which may be used in Step (A) of the process according to the present invention, where it is carried out in the vapour phase, may be mentioned inter alia (i) fluorination catalysts based on metal oxides, halides or oxyhalides or mixed metal oxides/halides/oxyhalides, for example chromia or alumina; (ii) other metallic oxides/halides/oxyhalides supported on chromia or alumina, for example oxides of zinc, iron, magnesium or nickel; and (iii) metal oxides/halides/oxyhalides, or mixed metal oxides/halides/oxyhalides supported on carbon.
• the fluorination catalyst is dried and subjected to a pretreatment, eg with hydrogen fluoride, prior to use.
• Step (A) in the process of the present invention is carried out in the vapour phase, are disclosed in our EP 0,502,605 and WO 93/25508, the disclosures in which are incorporated herein by way of reference.
• the fluorination catalyst may be compressed into pellets and used in the vapour phase in a fixed bed or, alternatively, catalysts of appropriate particle size may be used in a fluidised bed.
• the product stream from Step (A) may contain under-fluorinated propenes and propanes, eg isomers of dichloro-pentafluoropropane such as HCFC 225 da, which can either be recycled to Step (A) for conversion into HCFC 226da or, optionally, fed to Step (C).
• under-fluorinated propenes and propanes eg isomers of dichloro-pentafluoropropane such as HCFC 225 da, which can either be recycled to Step (A) for conversion into HCFC 226da or, optionally, fed to Step (C).
• Step (B) of the process according to the present invention separation of the HCl liberated in Step (A) from the product stream therefrom is typically carried out by distillation.
• Step (C) in the process according to the present invention is carried out in the vapour phase over a suitable fluorination catalyst in the temperature range 200-450°C, using a molar feed ratio of HF:HCFC 226da of between 1 :1 and 50:1, preferably between 1 :1 and 20:1 and a contact time of 0.2 -120 sees., preferably 0.5 - 30 sees.
• the reaction can be carried out within a wide range of pressures, from subatmospheric to superatmospheric, preferably from 1-50 bar.
• a suitable fluorination catalyst for use in Step (C) of the process according to the present invention may be chosen from the aforementioned fluorination catalysts for use in carrying out Step (A).
• Preferred fluorination catalysts for use in Step C are disclosed in our EP 0,502,605 and WO 93/25508.
• the process thereof is carried out in systems containing only one distillation column for the separation of byproduct HCl.
• the product stream from Step (C) is combined with the product stream from Step (A) and fed to a distillation column for the separation of HCl as is more fully described hereinafter in relation to Figure 1.
• both Steps (A) and (B) are carried out in the vapour phase
• the product stream from Step (C) is combined with the product stream from Step (A) and fed to a distillation column for the separation of HCl as is more fully described hereinafter in relation to Figure 1.
• both Steps in which both Steps
• Step (A) and (B) are carried out in the vapour phase, the product stream from Step (C) is combined with starting material and fed to Step (A) and the product stream from Step (A) is fed to a distillation column/condenser for the separation of HCl as is more fully described hereinafter in relation to Figure 2.
• Step (A) is carried out in the liquid phase
• the product stream from Step (C) is combined with a portion of the product stream from Step (A) and fed to a distillation column for the separation of HCl as is more fully described hereinafter in relation to Figure 3.
• Figure 1 illustrates a so-called Parallel Reactor Configuration
• Figure 2 illustrates a so-called Reverse Series Reactor Configuration
• Figure 3 illustrates a process comprising a liquid phase HCFC 226da production stage and a vapour phase HFC 227ea production stage; and Figure 4 illustrates a so-called Two HCl-Still Process Configuration.
• reactor (102), in which HCFC 226da is formed in the presence of a suitable vapour phase fluorination catalyst in Step (A), is fed with stream (113) containing HHCP and HF in a molar ratio of at least 7:1, and stream (112) containing underfluorinated precursors to HCFC 226da.
• Stream (104), the off-gas from reactor (102) containing HCFC 226da, is combined with stream (103), the off-gas from reactor (101), and fed to distillation column (106) via line (105).
• HCl is removed from column (106) in stream (107) in Step (B), while HF, HFC 227ea, HCFC 226da and underfluorinated HCFC 226da precursors are removed from the base of column (106) via stream (108) and fed to distillation column (109).
• the HFC 227ea HF azeotrope is removed from column (109) in stream (110) and subjected to further purification in order to obtain product HFC 227ea.
• a side-stream (111) containing HF and HCFC 226da is removed from column (109) and fed to reactor (101) in which HFC 227ea is formed in the presence of a suitable vapour phase fluorination catalyst in Step (C).
• Stream (112), containing underfluorinated precursors to HCFC 226da is removed from the bottom of distillation column (109) and fed to reactor (102).
• feedstock HHCP and HF is fed to the process via stream (202) and mixed with the off-gas from reactor (201) and the recycle stream (212) to form the feedstream (203) to reactor (204) in which HCFC 226da is formed in Step (A) in the presence of a suitable vapour phase fluorination catalyst.
• Stream (205), containing the off-gas from (204), is fed to distillation column (206) in which HCl is removed as an overhead product via stream (207) in Step (B).
• Stream (208), containing HF, HFC 227ea, HCFC 226da, and underfluorinated precursors of HCFC 226da is removed as bottoms stream from distillation column (206) and fed to distillation column (209).
• Stream (210), containing the HFC 227ea/HF azeotrope, is removed as an overheads stream from distillation column (209) for further work-up to obtain product HFC 227ea.
• a side-stream (211) containing HF and HCFC 226da is removed from column (209) and fed to reactor (201) in which HCFC 226da is reacted with HF in Step (C) in the presence of a suitable vapour phase fluorination catalyst to form HFC 227ea.
• Stream (212), containing underfluorinated precursors to HCFC 226da is removed from the bottom of distillation column (209) and fed to reactor (204).
• the operating temperature of reactor (204) in which Step (A) is carried out is less than that of reactor (201) in which Step (C) is carried out to reduce the extent of back reaction of HFC 277ea formed in (201) to HCFC 226da in reactor (204).
• a feedstream (301) comprising HHCP and HF is fed to liquid-phase reactor (302), in which Step (A) is carried out, charged with a suitable liquid-phase fluorination catalyst.
• the off-gas from the reactor, stream (303), is fed to separation column (304) from which a heavies stream (305) containing HF and underfluorinated precursors to HCFC 226da and a lights stream (306) containing HCl, HF and HCFC 226da, are removed.
• Stream (305) is returned to reactor (302).
• Stream (306) is combined with stream (314), containing HF, HFC 227ea and unconverted HCFC 226da from the HFC 227ea production stage, and fed to distillation column (307) in which Step (B) is carried out, from which an overheads stream (308) containing HCl, and a bottoms
• stream (309) containing HF,HFC 227ea and HCFC 226da are removed.
• Stream (309) is fed to distillation column (310) from which stream (311), containing the HFC 227ea HF azeotrope is removed as an overheads stream for further work-up in order to obtain product HFC 227ea.
• the bottoms product (312) from column (310), containing HF and HCFC 226da, is fed to reactor (313) in which Step (C) is carried out in which HCFC 226da is reacted with HF in the presence of a suitable vapour phase fluorination catalyst to form HFC 227ea.
• Stream (314), containing the off-gas from reactor (313) is combined with stream (306) as described above.
• stream (401) containing HHCP and HF is combined with stream (406) containing underfluorinated HCFC 226da precursors and fed as a vapour to reactor (402) charged with a suitable vapour-phase fluorination catalyst in which Step (A) is carried out.
• the off-gas (403) from reactor (402) is fed to a distillation column (404) in which Step (B) is carried out in which HCl is removed as lights stream (405).
• a bottoms stream (406) of underfluorinated HCFC 226da precursors is recycled to reactor (402) and a side-stream (407) of HF and HCFC 226da is combined with a HF and HCFC 226da recycle stream (415) and fed to reactor (408) in which Step (C) is carried out.
• Reactor (408) is charged with a suitable vapour-phase fluorination catalyst.
• the off-gas (409) from reactor (408), containing HF, HCFC 226da, HFC 227ea and HCl, is fed to distillation column (410) in which HCl is removed as overheads stream (41 1).
• HF, HFC 227ea and HCFC 226da is removed as bottoms stream (412) and fed to distillation column (413).
• distillation column (413) an overhead stream (414), containing HFC 227ea/HF azeotrope, is separated from the bottoms stream (415) containing HF and HCFC 226da, which is recycled to reactor (408).
• Example 1 The present invention is illustrated but not limited by the following Examples.
• Example 1 The present invention is illustrated but not limited by the following Examples.
• HCFC 226da is formed in good yield and selectivity in Step (A) of the process according to the present invention
• This Example is a Comparative Test which illustrates the reaction of a

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• 1998
  • 1998-02-06 GB GBGB9802487.0A patent/GB9802487D0/en not_active Ceased
• 1999
  • 1999-01-19 EP EP99902652A patent/EP1051377A1/de not_active Withdrawn
  • 1999-01-19 WO PCT/GB1999/000175 patent/WO1999040053A1/en not_active Application Discontinuation
  • 1999-01-19 JP JP2000530485A patent/JP2002502834A/ja active Pending
  • 1999-01-19 AU AU22871/99A patent/AU2287199A/en not_active Abandoned
  • 1999-01-25 ZA ZA9900531A patent/ZA99531B/xx unknown
  • 1999-02-05 AR ARP990100484A patent/AR018067A1/es unknown

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