Classifications

• • 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
  • C07C17/25—Preparation of halogenated hydrocarbons by splitting-off hydrogen halides from halogenated hydrocarbons

Definitions

• the present invention relates to a process for preparing (hydro) (chloro) fluoroolefins. It relates more particularly to a process for the preparation of (hydro) (chloro) fluoropropenes.
• WO 2004/037913 teaches the use of tetrafluoropropene and pentafluoropropene as low GWP (low global warming potential) refrigerants.
• hydrofluoro-olefins are generally obtained by the dehydrohalogenation reaction.
• Tetrafluoropropene can also be obtained by the dehydrofluorination reaction of pentafluoroethane (US 5986151). Trifluoropropene and tetrafluoropropene are also formed during the fluorination reaction of pentachloroethane with HF in the presence of a catalyst (WO 9812161).
• Another route of preparation of trifluoropropene and / or tetrafluoropropene is to react trichloropropene with HF in the presence of a catalyst (US 5811603).
• the fluorination reactions in the liquid phase require to be effective to use a reaction medium rich in HF and SbCl 5 (or SbCl x F y) and temperatures between 80 and 120 0 C.
• the HF anhydrous form of liquid phase forms with SbCl 5 a very corrosive superacidic medium.
• the present invention describes a process for the preparation of
• the (hydro) haloalkane of general formula (II) may be derived from a telomerization reaction between a haloalkane preferably having a carbon atom and a haloalkene.
• a represents an integer equal to 3 or 4 and advantageously a is equal to 3.
• the preferred (hydro) (chloro) fluoroolefins are trifluoropropene
• the fluorination step is advantageously carried out in the presence of anhydrous hydrofluoric acid.
• the process according to the invention may further comprise a step of dehydrohalogenation or hydrofluorination of the product or fluorinated products resulting from the reaction in the presence of at least one ionic liquid.
• a (hydro) haloalkane of general formula (II) is reacted with a equal to 3, b 'equal to zero, c' equal to 5 or 6 and X preferably represents C1, with anhydrous hydrofluoric acid in the presence of a catalyst comprising at least one ionic liquid to give a fluorinated compound of formula CsH n Fs-H with n equal to 2 or 3.
• the fluorinated compound after optional separation, is then subjected to a dehydrofluorination step to give the desired hydrofluoroolefin.
• a (hydro) haloalkene of general formula (III) is reacted with a equal to 3, b "equal to zero, c" equal to 4 and X preferably represents Cl, with anhydrous hydrofluoric acid in the presence of a catalyst comprising at least one ionic liquid to give a fluorinated compound of formula CsH 2 FpX 4 -P , p representing a value equal to 3 or 4 and / or of formula CsH n F 8 - H with n being able to take the value 2 or 3.
• the products resulting from the fluorination step comprise a compound of formula CsH n F 8-n , the latter is subjected to a dehydrofluorination step.
• 2-chloro, 1, 1, 1-trifluoropropene (1233 xf) and / or 1,1,1,2-tetrafluoropropene (1234 yf) can or can be obtained from 1, 1, 2,3-tetrachloropropene (1230xa) by fluorination in the liquid phase in the presence of at least one ionic liquid as catalyst.
• 1,1,1,2-tetrafluoropropene (1234 yf) can also be obtained from 2-chloro, 1,1,1-trifluoropropene (1233xf) by fluorination in the liquid phase in the presence of at least one ionic liquid. as a catalyst to give 2-chloro, 1, 1, 1, 2-tetrafluoropropane (244 bb) and / or 1,1,1,2,2 pentafluoropropane (245 bb) which is or is subsequently subjected to a dehydrohalogenation step either in the liquid phase or in the gas phase.
• 1,1,1,3-tetrafluoropropene (1234 ze) can be obtained from 3-chloro, 1,1,1-trifluoropropene (1233 zd).
• 1,1,1,2-tetrafluoropropene (1234 yf) can be obtained from 1,1,1,2-tetrachloro-2-fluoropropane (241 bb) by fluorination in the liquid phase in the presence of less an ionic liquid as a catalyst.
• Ionic liquids that may be suitable are derived from Lewis acids based on aluminum, titanium, niobium, tantalum, tin, antimony, nickel, zinc or iron.
• Ionic liquids are non-aqueous salts of ionic character which are liquid at moderate temperatures (preferably below 120 ° C.).
• the ionic liquids preferably result from the reaction between an organic salt and an inorganic compound.
• the ionic liquids are preferably obtained by reacting at least one halogenated or oxyhalogenated Lewis acid based on aluminum, titanium, niobium, tantalum, tin, antimony, nickel, zinc or iron with a salt of general formula Y + A - , in which A " denotes a halide anion (bromide, iodide and, preferably chloride or fluoride) or hexafluoroantimoniate (SbF ⁇ " ) and Y + a quaternary ammonium, quaternary phosphonium or sulphonium cation ternary Halogenated Lewis acid based on aluminum, titanium, niobium, tantalum, antimony, nickel, zinc or iron may be a chlorinated, brominated, fluorinated or mixed derivative, for example a Chlorofluorinated acid: Chlorides, fluorides or chlorofluorides of the following formulas may be mentioned in particular: TiCI x Fy with
• the following compounds are preferably used: TiCl 4 , TaCl 5 + TaF 5 , NbCl 5 + NbF 5 , SbCl 5 , SbFCI 4 , SbF 2 Cl 3 , SbF 3 Cl, SbF 4 Cl, SbF 5 and SbCl 5 + SbF 5 . More particularly preferred are the antimonial compounds.
• the cation Y + may respond to one of the following general formulas:
• ammonium, phosphonium or sulfonium cation Y + may also be part of a saturated or unsaturated heterocyclic ring, or aromatic ring having from 1 to 3 nitrogen, phosphorus or sulfur atoms, and to respond to one or other of following general formulas:
• R 1 and R 2 are as defined above.
• a salt containing 2 or 3 ammonium, phosphonium or sulfonium sites in their formula may also be suitable.
• Examples of salts Y + A " include tetraalkyl ammonium chlorides and fluorides, tetraalkyl phosphonium chlorides and fluorides, and trialkyl sulfonium chlorides and fluorides, alkyl pyridinium chlorides and fluorides, chlorides, fluorides and bromides.
• the ionic liquids may be prepared in a manner known per se by appropriate mixing of the halogenated or oxyhalogenated Lewis acid and the organic salt Y + A " .
• Advantageously preferred ionic liquids are those derived from a Lewis acid / organic salt molar ratio strictly greater than 1: 1.
• the liquid phase fluorination step using as catalyst an ionic liquid can be carried out batchwise, semi-continuously and continuously.
• the molar amount of HF on the molar amount of starting material is between 2 and 50 and preferably between 10 and 30.
• the molar amount of HF fed to the molar amount of feedstock fed is at least equal to the stoichiometric ratio.
• the amount of catalyst depends on the operating conditions, the reaction medium (in the case of a continuous process) but also the intrinsic activity of the catalyst. This amount is between 0.5 and 90% (molar) of the reaction medium.
• the temperature at which the fluorination reaction is carried out is generally between 30 and 180 ° C., preferably between 80 and 130 ° C.
• the pressure at which the reaction is carried out in semi-continuous or continuous modes is chosen so as to maintain the reaction medium in the liquid phase. It is generally between 5 and 50 bars and preferentially between
• the operating pressure chosen is in general the saturation vapor pressure of I 1 HF at the desired reaction temperature.
• the condenser temperature is set according to the amount and nature of the products that can be removed during the reaction. It is generally between -50 and 150 ° C. and preferably between 0 and 100 ° C.
• a stainless steel reactor or alloys such as MONEL, INCONEL or HASTELLOY may be suitable for fluorination.
• the fluorination step in the presence of an ionic liquid is less corrosive.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Catalysts (AREA)
• Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)

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• 2007
  • 2007-05-31 FR FR0755357A patent/FR2916755B1/fr not_active Expired - Fee Related
• 2008
  • 2008-05-13 CN CN200880016545A patent/CN101679151A/zh active Pending
  • 2008-05-13 EP EP08805769A patent/EP2148849A2/de not_active Withdrawn
  • 2008-05-13 WO PCT/FR2008/050821 patent/WO2008149011A2/fr active Application Filing
  • 2008-05-13 US US12/601,365 patent/US20100191025A1/en not_active Abandoned

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