EP0724553A1 - Procede de production de 1,1-dichlorotetrafluoroethane de haute purete - Google Patents

Procede de production de 1,1-dichlorotetrafluoroethane de haute purete

Info

Publication number
EP0724553A1
EP0724553A1 EP94926570A EP94926570A EP0724553A1 EP 0724553 A1 EP0724553 A1 EP 0724553A1 EP 94926570 A EP94926570 A EP 94926570A EP 94926570 A EP94926570 A EP 94926570A EP 0724553 A1 EP0724553 A1 EP 0724553A1
Authority
EP
European Patent Office
Prior art keywords
fluorination
parts
weight
product
cfc
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP94926570A
Other languages
German (de)
English (en)
Inventor
Velliyur Nott Mallikarjuna Rao
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
EIDP Inc
Original Assignee
EI Du Pont de Nemours and Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by EI Du Pont de Nemours and Co filed Critical EI Du Pont de Nemours and Co
Publication of EP0724553A1 publication Critical patent/EP0724553A1/fr
Withdrawn legal-status Critical Current

Links

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
    • C07C19/10—Acyclic saturated compounds containing halogen atoms containing fluorine and chlorine
    • C07C19/12—Acyclic saturated compounds containing halogen atoms containing fluorine and chlorine having two carbon 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
    • C07C17/00—Preparation of halogenated hydrocarbons
    • C07C17/35—Preparation of halogenated hydrocarbons by reactions not affecting the number of carbon or of halogen atoms in the reaction
    • C07C17/358—Preparation of halogenated hydrocarbons by reactions not affecting the number of carbon or of halogen atoms in the reaction by isomerisation
    • 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 processes for the manufacturing of 1, 1-dichlorotetrafluoroethane (i.e., CF3CCI2F or CFC-114a) , and more particularly to processes for manufacturing CF3CCI 2 F substantially free of its isomer, 1, 2-dichlorotetrafluoroethane (i.e., CC1F CC1F 2 or CFC-114) .
  • 1-Dichlorotetrafluoroethane is of interest as an intermediate to 1, 1, 1, 2-tetrafluoroethane (i.e., CF3CH2F or HFC-134a) which can be obtained via catalytic hydrogenolysis of its carbon-chlorine bonds using a supported metal hydrogenation catalyst (see e.g., C. Gervasutti et al. , J. Fluorine Chem., 1981/82, 19, pgs. 1-20) .
  • HFC-134a is an environmentally acceptable potential replacement for chlorofluorocarbon (i.e., CFC) refrigerants, blowing agents, aerosol propellants and sterilants that are being viewed with concern in connection with the destruction of stratospheric ozone. It is highly desired that the 1, 1-dichlorotetrafluoro ⁇ ethane employed in the hydrogenolysis route to HFC-I34a has as low a content. of 1,2-dichlorotetrafluoroethane as practicable since the presence of CFC-114 during hydrogenolysis can lead to formation of 1, 1,2,2-tetra ⁇ fluoroethane (i.e., CHF2CHF2 or HFC-134; see e.g., J. L.
  • CFC chlorofluorocarbon
  • HFC-134 mixed in HFC-134a may be objectionable for some applications depending on concentration and, since the two isomers boil only 7°C apart, separation of the isomers in high purity is difficult.
  • Commercial processes using either chlorofluorination of C2CI 4 or fluorination of C 2 CI6 typically yield CFC-114 as the major isomer with CFC-114a as a minor component.
  • CFC-114a 1, 1, 1-trichlorotrifluoroethane (i.e., CCI3CF3 or CFC-113a) is typically produced as a minor component when its isomer, 1, 1, 2-trichlorotrifluoroethane (i.e., CCIF2CCI 2 F or CFC-113) is manufactured using similar processes.
  • trichlorotrifluoroethanes and dichlorotetrafluoroethanes involves reaction of hydrogen fluoride (i.e., HF) with tetrachloroethylene (i.e., C2CI 4 ) plus chlorine, or with its chlorine addition product, hexachloroethane (i.e., C 2 CI6) , in the liquid phase in the presence of an antimony pentahalide as catalyst.
  • hydrogen fluoride i.e., HF
  • tetrachloroethylene i.e., C2CI 4
  • chlorine or with its chlorine addition product, hexachloroethane (i.e., C 2 CI6)
  • the C2CI3F3 and C2CI2F 4 products consist predominantly of the more symmetrical isomers, that is, CCIF2CCI2F and CCIF2CCIF2, respectively (the symmetrical term referring to the distribution of the fluorine substituents in the molecule) .
  • U.S. Patent No. 5,055,624 discloses a process for the selective preparation of CFC-114a by fluorination of pure CFC-113a or mixtures of it with CFC-113 with anhydrous HF.
  • the reaction is done in the liquid phase at 70° to 170°C, under pressure in the presence of an antimony compound of the formula SbF x Cl 5 _ x , where x is a number from 1 to 5.
  • SbF x Cl 5 _ x an antimony compound of the formula SbF x Cl 5 _ x , where x is a number from 1 to 5.
  • SbF x Cl 5 _ x antimony compound of the formula SbF x Cl 5 _ x
  • x is a number from 1 to 5.
  • CFC-113 was reacted with HF under a preferred set of conditions at 151°C to afford a product which contained 99.6 mol% CFC-113 and 0.4 mol% CFC-114.
  • European Patent Application No. 317,981-A3 discloses a process for producing CCI 2 FCF3 which comprises isomerizing CCI 2 FCCIF 2 to form CCI3CF3, followed by fluorination with hydrogen fluoride.
  • the purest CCI 2 FCF3 obtained has a molar ratio of CCI2FCF3 to CCIF2CCIF2 of about 53:1.
  • the highest purity CCI3CF.3 feed contains about 14% CCI2FCCIF2 and 86% CCI3CF3.
  • a process is provided in accordance with this invention for producing CCI 2 FCF3 substantially free of CCIF2CCIF2.
  • the process comprises the steps of (i) contacting a feed mixture consisting essentially of
  • C2CI3F3 where the ratio of CCI2FCCIF2 to CCI3CF3 is at least about 1:9 with an isomerization catalyst to produce an isomerization product wherein there is less than about 50,000 parts by weight CCI2FCCIF 2 per million parts CCI3CF3; (ii) contacting the isomerization product with HF in the vapor phase in the presence of a fluorination catalyst comprising trivalent chromium at an elevated temperature below 400°C selected to provide a fluorination product containing C2CI2F 4 and C 2 CI3F3 wherein there is less than 10,000 parts by weight CCIF2CCIF 2 per million parts by weight CCI2FCF3 and wherein the parts by weight CCI2FCCIF2 per million parts CCI3CF3 is greater than the parts by weight CCI2FCCIF2 per million parts CCI3CF3 in the isomerization product; (iii) recovering the C 2 CI 2 F 4 from the fluorination product; and (iv) recycling
  • FIG. 1 is a schematic representation of an embodiment of this invention.
  • the process of this invention involves the vapor phase catalytic fluorination of trichlorotrifluoro ⁇ ethane.
  • CCI 2 FCF 3 substantially free of CCIF 2 CCIF 2 is produced.
  • the C2CI3F3 consists mainly of CCI3CF3 and less than about 50,000 parts by weight CCI2FCCIF2 per million parts CCI3CF3.
  • the C 2 CI3F3 contains at least about 100 ppm CCI2FCCIF2.
  • C2CI3F3 isomer mixtures recovered from a CCI2FCCIF2 isomerization reaction typically contain from about 300 to 1000 ppm of CCI2FCCIF2 per million parts CCI3CF3.
  • the fluorination is conducted under conditions where CCI3CF3 is preferentially fluorinated (e.g., at an elevated temperature no higher than about 400°C) .
  • the fluorination process according to the present invention can be conducted batchwise, but is preferably conducted continuously in a manner generally known to the art for conducting catalyzed vapor phase fluorination reactions.
  • the C2CI3F3 mixtures are reacted with hydrogen fluoride using a catalyst comprising trivalent chromium.
  • a catalyst comprising trivalent chromium can include other components to increase catalyst activity and/or life such as one or more divalent metal cations (e.g., zinc, magnesium, and/or cobalt) .
  • the trivalent chromium catalyst may be unsupported (e.g., Cr2 ⁇ 3) or supported (e.g., on alumina, aluminum fluoride, magnesium fluoride or carbon) .
  • Suitable vapor-phase fluorination catalysts include trivalent chromium halides (e.g., CrCl3 and/or CrF3) supported on carbon.
  • a preferred catalyst is CrF3 on carbon and is disclosed in U.S. Pat. No. 3,632,834, the contents of which are incorporated herein by reference. While any suitable carbon support may be used, a preferred carbon support is acid-washed prior to depositing trivalent chromium on it.
  • Suitable trivalent chromium catalysts may be prepared by treating the carbon used as catalyst support with an acid, preferably with two acids .
  • the support is washed with deionized water after acid treatment and dried; and the chromium halide is then deposited thereon using deposit techniques well known in the art (see e.g.. Example 1 of U.S. 3,632,834) .
  • the chromium content (expressed as CrCl3) is from about 5 to 50 weight percent of the carbon-supported catalyst.
  • Acid treatment typically uses an acid other than hydrofluoric acid. Preferred acids used for the acid treatment contain neither phosphorus nor sulfur. Examples of acids which may be used in the first acid wash during the catalyst preparation process include organic acids such as acetic acid and inorganic acids such as HC1 or HNO 3 . Preferably hydrochloric acid or nitric acid is used.
  • the second acid treatment when employed, advantageously uses hydrofluoric acid. Normally, the carbon is treated with acid such that after such treatment the carbon contains less than about 0.1% by weight ash.
  • the carbon support can be in the form of powder, granules, extrudates, or pellets, etc.
  • the acid treatment may be accomplished in several ways.
  • a suitable procedure is as follows.
  • a carbon support is soaked overnight with gentle stirring in a 1 molar solution of the acid prepared in deionized water.
  • the carbon support is then separated and washed with deionized water until the pH of the washings is about 3.
  • the carbon support is .then soaked again with gentle stirring in a 1 molar solution of the acid prepared in deionized water for 12 to 24 hours.
  • the carbon support is then finally washed with deionized water until the washings are substantially free of the anion of the acid (e.g., Cl ⁇ or N ⁇ 3 ⁇ ) , when tested by standard procedures.
  • the carbon support is then separated and dried at about 120°C.
  • the washed carbon is then soaked, if necessary, in 1 molar HF prepared in deionized water for about 48 hours at room temperature with occasional stirring.
  • the carbon support is separated and washed repeatedly with deionized water until the pH of the washings is greater than .
  • the carbon support is then dried followed by calcination at about 300°C for about 3 hours in air prior to its use as a support.
  • U.S. Patent No. 5,136,113 for further details relating to producing acid-washed carbon catalysts .
  • the fluorination reaction is generally conducted in a reaction zone for the fluorination.
  • the reaction zone may contain more than one reactor, multiple feed lines, as well as interstage cooling or heating, addition of reactants, diluents, recycle streams, etc.
  • multiple reactors may be used to stage the degree of fluorination so that undue temperature rise and overfluorination are avoided.
  • the reaction product is normally recovered at the end of the reaction zone. If necessary, the reaction products, intermediates and/or by-products can be removed at various stages of the reaction zone and if desired recycled to different parts of the reaction zone.
  • HF and CFC-113a can be fed to a reaction zone at more than one feed location.
  • CFC-114a is generally recovered from the end of the reaction zone.
  • Suitable fluorination reaction temperatures are normally from about 250°C to 400°C A preferred temperature range is from 275°C to 375°C, with temperatures ranging from 300°C to 350°C being particularly preferred.
  • the HF-C2CI3F3 ratio is normally from 0.2:1 to 4:1, and preferably ranges from 0.25:1 to 2:1.
  • Pressure is not critical. Atmospheric and superatmospheric pressures (e.g., from about 100 kPa to about 7000 kPa) are the most convenient and are therefore preferred.
  • the above reaction variables together with the catalyst loading are balanced one against the other such that in the fluorination products there is less than 10,000 parts by weight CCIF2CCIF2 per million parts CCI2FCF3.
  • the fluorination product mixture also typically contains small amounts of CCIF2CF3 (CFC-115) , unreacted C2CI3F3 isomers, HF and HC1.
  • the fluorination product is separated to provide recovery of C2CI 2 F .
  • conventional separation using one or more distillation column (s) is employed. It is noted that azeotropes of HF with various halocarbons such as CFC-114a and/or CFC-113a can form during distillation.
  • the separation may also include one or more decanter(s) .
  • the lower boiling materials e.g., HF, HC1, CFC-115) are normally separated from the CFC-113 isomers.
  • the product mixture (prior to recovery of CCI2FCF3) contains at least 10 mole % CCI 2 FCF3 (CFC-114a) .
  • the CFC-113 isomers from the fluorination product which are normally enriched in CFC-113 as a result of selective fluorination of CFC-113a, are fed along with additional CFC-113. to an isomerization zone, where the CFC-113 is substantially isomerized to CFC-ll3a.
  • HF should be removed from the C2CI3F 4 prior to contact with the isomerization catalyst.
  • the CFC-113 is isomerized to CFC-113a using an aluminum chloride catalyst as disclosed in Example I of U.S. Pat. No. 2,598,411. Many aluminum trihalide catalysts can be employed.
  • a preferred catalyst is an anhydrous aluminum trichloride which has been micropulverized (i.e., mechanically comminuted by crushing, ball milling, rod milling, grinding or the like) to provide a surface area of greater than about 0.8 m 2 /g and has been activated by treatment under agitation with at least about 10 grams CCI2FCCFI2 per gram of aluminum trichloride.
  • micropulverized i.e., mechanically comminuted by crushing, ball milling, rod milling, grinding or the like
  • the CFC-113a from the isomerization may be recycled in accordance with this invention to the fluorination step.
  • the CFC-113a from the isomerization zone is reacted with HF in the reaction zone to afford high purity CFC-114a.
  • the latter compound which can be isolated from the fluorination product or can be recovered as an azeotrope in the presence of HF, can then be converted by hydrogenolysis to CH2FCF3 (HFC-134a) , a non-ozone depleting refrigerant.
  • a mixture of C2CI3F3 isomers containing substantial CFC-113 is fed through line (211) to an isomerizer (210) .
  • the isomerizer effluent consisting of a mixture of C 2 CI3F3 isomers containing predominantly CFC-113a is fed through line (212) to a fluorination reactor (220) .
  • HF is fed to reactor (220) through line (221) .
  • the fluorination reactor effluent containing predominantly CFC-114a, unreacted C2CI3F3 isomers, HF and HCl is fed through line (222) to a distillation column (230) .
  • C 2 CI 2 F 4 (CFC-114a substantially free of CFC-114), HF and HCl is collected at the top of the column and recovered through line (232) .
  • CFC-113 from the bottom of column (230) , is fed through line (231) back to the isomerizer (210) along with additional CFC-113 through line (213) .
  • the reactors and their associated feed lines, effluent lines and associated units should be constructed of materials resistant to hydrogen fluoride, hydrogen chloride and chlorine.
  • Typical materials of construction include stainless steels, in particular of the austenitic type, and the well-known high nickel alloys. such as Monel® nickel-copper alloys, Hastelloy® nickel- based alloys and, Inconel® nickel-chromium alloys.
  • polymeric plastics as polytrifluorochloroethylene and polytetrafluoroethylene, generally used as linings. Practice of the invention will become further apparent from the following non-limiting examples.
  • the reactor effluent was sampled on-line with a Hewlett Packard HP 5890 gas chromatograph using a 20 foot (6.1 m) long, one-eighth inch (0.32 cm) diameter, column containing KrytoxTM perfluorinated polyether on an inert support and a helium flow of 35 mL/min. Gas chromatographic conditions were 70°C for three minutes followed by temperature programming to 180°C at a rate of 6°C/minute. The table percentages are in mole percent.
  • ⁇ a >115 is CCIF2CF3 (b) 114a is CCI2FCF3 (c) 113 is CC1 2 FCC1F 2 ( ) 113a is CCI3CF3
  • the CFC-114 was below the detection limit of about 1000 ppm.
  • (a) 123 is CHCI2CF3
  • the CFC-114 was below the detection limit of about 1000 ppm.
  • CFC-114 was below the detection limit of about 1000 ppm..
  • CFC-114 was below the detection limit of about 1000 ppm.

Landscapes

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

Abstract

L'invention concerne un procédé de production de CCl2FCF3 sensiblement exempt de CC1F2CC1F2. Le procédé consiste à mettre en contact un mélange d'alimentation constitué essentiellement de C2Cl1F3, dans lequel le rapport de CCl2FCClF2 sur CCl3CF3 est d'au moins environ 1:9, avec un catalyseur d'isomérisation, pour produire un produit d'isomérisation contenant moins d'environ 50 000 parties en poids de CCl2FCC1F2 par million de parties de CCl3CF3. Le produit d'isomérisation est mis en contact ave du HF en phase vapeur en présence d'un catalyseur de fluoration comprenant du chrome trivalent, une température élevée inférieure à 400 °C et chosie pour donner un produit de fluoration contenant du C2Cl2F4 et du C2Cl3F3, dans lequel il y a moins de 10,000 parties en poids de CClF2CClF2 par million de parties en poids de CCl2FCF3 et dans lequel le nombre de parties en poids de CCl2FCC1F2 par million de parties de CCl3CF3 est supérieur au nombre de parties en poids de CC12FCC1F2 par million de parties de CCl3CF3 dans le produit d'isomérisation. Le C2Cl2F4 du produit de fluoration est récupéré; et le C2Cl3F3 du produit de fluoration est recyclé dans l'étape d'isomérisation avec une quantité additionnelle de CCl2FCC1F2 qui est au moins égale à la quantité de C2Cl2F4 récupérée dans le produit de fluoration et qui est suffisante pour avoir le rapport souhaité de CCl2FCC1F2 sur CCl3CF3 dans le produit d'alimentation.
EP94926570A 1993-11-01 1994-09-01 Procede de production de 1,1-dichlorotetrafluoroethane de haute purete Withdrawn EP0724553A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US14685393A 1993-11-01 1993-11-01
US146853 1993-11-01
PCT/US1994/009531 WO1995012564A1 (fr) 1993-11-01 1994-09-01 Procede de production de 1,1-dichlorotetrafluoroethane de haute purete

Publications (1)

Publication Number Publication Date
EP0724553A1 true EP0724553A1 (fr) 1996-08-07

Family

ID=22519265

Family Applications (1)

Application Number Title Priority Date Filing Date
EP94926570A Withdrawn EP0724553A1 (fr) 1993-11-01 1994-09-01 Procede de production de 1,1-dichlorotetrafluoroethane de haute purete

Country Status (3)

Country Link
EP (1) EP0724553A1 (fr)
JP (1) JPH09505566A (fr)
WO (1) WO1995012564A1 (fr)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5446216A (en) * 1993-11-01 1995-08-29 E. I. Du Pont De Nemours And Company Process for manufacture of high purity 1,1-dichlorotetrafluoroethane

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0788326B2 (ja) * 1987-11-26 1995-09-27 旭硝子株式会社 １，１−ジクロロ−１，２，２，２−テトラフルオロエタンの製造方法
CA2012792A1 (fr) * 1989-06-14 1990-12-14 Robert C. Zawalski Procede de preparation de chlorofluorocarbures par l'entremise d'un catalyseur a base de trihalogenure d'aluminium active genere in situ et produits en resultant
DE69006820T2 (de) * 1989-10-30 1994-07-28 Du Pont Verfahren zur Herstellung von 1,1-Dichlorotetrafluorethan.

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9512564A1 *

Also Published As

Publication number Publication date
JPH09505566A (ja) 1997-06-03
WO1995012564A1 (fr) 1995-05-11

Similar Documents

Publication Publication Date Title
AU628912B2 (en) Aluminum fluoride catalyst compositions and use thereof in a chlorofluorination process for preparing 1,1-dichloro-1,2,2,2-tetrafluoroethane
WO1992002476A1 (fr) Equilibrage catalytique d'halocarbones selectionnes
JPH04503215A (ja) １，１，１，２―テトラフルオロエタンの製造
US5481051A (en) 2,2-dichlorohexafluoropropane hydrogenolysis
US5446216A (en) Process for manufacture of high purity 1,1-dichlorotetrafluoroethane
US5523498A (en) Process for reducing the fluorine content of hydrofluorocarbons and hydrohalofluorocarbons
JPH09511515A (ja) ペンタフルオロエタンの製造
US5545774A (en) Process for the manufacture of 1,1,1,3,3,3-hexafluoropropane
JPH11158089A (ja) １，１，１，３，３−ペンタフルオロプロパンの合成
US5523501A (en) Catalytic hydrogenolysis
EP0714384A1 (fr) Procede de combinaison de molecules chlorees pour la synthese de produits fluores
US5831136A (en) Process for manufacture of high purity 1,1-dichlorotetrafluoroethane
AU655265B2 (en) Hydrogenolysis of halocarbon mixtures
JP2930697B2 (ja) １，１―ジクロロテトラフルオロエタンの製造方法
JPH10508016A (ja) ハイドロフルオロアルカンの製造
EP0724553A1 (fr) Procede de production de 1,1-dichlorotetrafluoroethane de haute purete
US5406009A (en) Catalytic equilibration to improve the relative yield of selected halocarbons
US5824828A (en) Process for manufacture of trichlorotrifluoroethanes
US20050020863A1 (en) Method of making fluorinated propanes
EP0724554A1 (fr) Procede de production de trichlorotrifluoroethanes
US5008476A (en) Process for the preparation of 1,1,1,2-tetrafluoroethane
US5243108A (en) Aluminum fluoride catalyst compositions and use thereof in a chlorofluorination process for preparing 1,1-dichloro-1,2,2,2-tetrafluoroethane
EP1542949B1 (fr) Procede de production de difluoromethane
WO1991013048A1 (fr) Fluorination par echange d'halogene

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 19960404

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): DE ES FR GB IT NL

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION HAS BEEN WITHDRAWN

18W Application withdrawn

Withdrawal date: 19960917