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WO1998027006A1 - Process for the production of active fluorine and intermediates involved in active fluorine production and use of this active fluorine - Google Patents

Process for the production of active fluorine and intermediates involved in active fluorine production and use of this active fluorine Download PDF

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Publication number
WO1998027006A1
WO1998027006A1 PCT/GB1997/003348 GB9703348W WO9827006A1 WO 1998027006 A1 WO1998027006 A1 WO 1998027006A1 GB 9703348 W GB9703348 W GB 9703348W WO 9827006 A1 WO9827006 A1 WO 9827006A1
Authority
WO
WIPO (PCT)
Prior art keywords
alkali metal
active fluorine
fluorine
reaction
fluorohalate
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.)
Ceased
Application number
PCT/GB1997/003348
Other languages
French (fr)
Inventor
Leigh Edward Wakefield
Barnaby John Whyte
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.)
Sellafield Ltd
Original Assignee
British Nuclear Fuels PLC
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 British Nuclear Fuels PLC filed Critical British Nuclear Fuels PLC
Priority to AU77379/98A priority Critical patent/AU7737998A/en
Publication of WO1998027006A1 publication Critical patent/WO1998027006A1/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B7/00—Halogens; Halogen acids
    • C01B7/24—Inter-halogen compounds
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B7/00—Halogens; Halogen acids
    • C01B7/19—Fluorine; Hydrogen fluoride
    • C01B7/20—Fluorine
    • C—CHEMISTRY; METALLURGY
    • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
    • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
    • C11D7/00—Compositions of detergents based essentially on non-surface-active compounds
    • C11D7/02—Inorganic compounds
    • C—CHEMISTRY; METALLURGY
    • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
    • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
    • C11D2111/00—Cleaning compositions characterised by the objects to be cleaned; Cleaning compositions characterised by non-standard cleaning or washing processes
    • C11D2111/10—Objects to be cleaned
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K3/00—Apparatus or processes for manufacturing printed circuits
    • H05K3/22—Secondary treatment of printed circuits
    • H05K3/26—Cleaning or polishing of the conductive pattern

Definitions

  • This invention relates to the production of active fluorine through an intermediate, such as alkali metal tetrafluorohalate, and to improvements in the production of those intermediates .
  • Alkali metal tetrafluorohalates are relatively stable materials which we have now established provide a convenient source of active fluorine.
  • Active fluorine sources have many uses such as specialised fluorinating agents and as a high performance cleaning agents due to their extremely reactive nature. They may also be used as a dry cleaning agent in the electronics industry. However, conventionally used sources of active fluorine in their form ready for use are highly dangerous substances .
  • the active fluorine produced from the source may be or include F, F 2 , C1F, C1F 3 , ClF 5 , IF 5 , IF 7 , BrF, BrF 3 , BrF 5 or mixtures thereof .
  • the gases produced may further include Cl 2 , Cl , I, I 2 , Br, Br 2 or mixtures thereof.
  • Active fluorine consists of highly energetic fluorine species.
  • a method for producing alkali metal fluorohalate comprising the direct fluorination of one or more alkali metal halides.
  • Preferably only one alkali metal halide is employed.
  • Preferably a potassium form is used.
  • the halate is preferably provided in the chlorate form, although the iodate or bromate forms may be used.
  • KCl is a preferred starting material, most preferably according to the reaction : -
  • the reaction is carried out at temperatures in the range of 15 to 250°C and most preferably 90 to 250°C.
  • the reaction temperature, and preferably the maximium reaction temperature may be between 190 to 325 °C, and more preferably may be between 220 and 270°C.
  • the reaction is preferably carried out in a vacuum system which excludes air and moisture.
  • vacuum system is meant a high pressure system capable of being evacuated to remove moisture and/or air.
  • the fluorine may be provided at elevated pressure.
  • at least the inital, fluorine pressure is between 1 and 10 atm, and more preferably between 2.5 and 5 atm.
  • the reaction is preferably carried out for a time period of at least 60 minutes, and more preferably a time period of between 80 and 400 minutes.
  • the fluorine may be scrubbed with sodium fluoride prior to the reaction to remove HF .
  • a cold trap for instance at less than -70°C, may be employed. The complete removal of HF from the fluorine is desirable .
  • the intermediate may be formed as a transitional state in the production of active fluorine or as an intermediate form for transportation and/or storage, preferably prior to conversion to active fluorine.
  • the reaction products may be purified prior to storage.
  • the alkali metal tetrafluorohalate is preferably provided in pellet form.
  • the alkali metal tetrafluorohalate may be RbClF 4 or CsClF 4 or any other suitable alkali metal.
  • the form may be used as a solid suitable for transportation.
  • KCIF 4 is particularly preferred.
  • the active fluorine is produced from the alkali metal tetrafluorohalate by thermal decomposition.
  • the active fluorine may be or include one or more of XF n , where X is Cl, Br or I , and n is 1, 3, 5 or 7.
  • alkali metal flurohalate preferably tetrafluorohalate
  • active fluorine produced from alkali metal fluorohalate, preferably tetrafluorohalate, produced according to the method of the first aspect.
  • the use of the active fluorine sources may be in cleaning or etching semi-conductor materials or apparatus or equipment involved in their production and processing.
  • alkali metal fluorohalate preferably tetrafluorohalate, produced according to the first aspect of the invention, as a transportable and/or storable source of active fluorine.
  • the fluorination is carried out at between 15-300°C and yields a dense melt. Temperatures of 90-200°C are appropriate to the potassium and caesium forms. The exclusion of water from the reaction vessel is important for obtaining the correct products .
  • a nickel reaction vessel was charged with KCl (0.31g, 0.0042mols) at room temperature. Still at room temperature, the vessel was charged with F 2 (2.86atm, 0.012mol) giving rise to an exothermic reaction almost instantly.
  • the system was then heated to a maximium of 263°C over a period of 90 minutes, before being allowed to cool.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Wood Science & Technology (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Abstract

An improved production technique for active fluorine is provided through the production of an intermediate, alkali metal fluorohalate form. The intermediate is formed by the direct fluorination of an alkali metal chloride. The technique offers advantages in terms of the cost and the ease of production of the intermediate and end products, as well as simplifying the transportation of the materials.

Description

PROCESS FOR THE PRODUCTION OF ACΗVE FLUORINE AND INTERMEDIATES INVOLVED IN ACΗVE FLUORINE PRODUCTION AND USE OF THIS ACΗVE FLUORINE
This invention relates to the production of active fluorine through an intermediate, such as alkali metal tetrafluorohalate, and to improvements in the production of those intermediates .
Alkali metal tetrafluorohalates are relatively stable materials which we have now established provide a convenient source of active fluorine.
Active fluorine sources have many uses such as specialised fluorinating agents and as a high performance cleaning agents due to their extremely reactive nature. They may also be used as a dry cleaning agent in the electronics industry. However, conventionally used sources of active fluorine in their form ready for use are highly dangerous substances .
Preferably the active fluorine produced from the source may be or include F, F2, C1F, C1F3, ClF5, IF5, IF7, BrF, BrF3, BrF5 or mixtures thereof . The gases produced may further include Cl2, Cl , I, I2, Br, Br2 or mixtures thereof. Active fluorine consists of highly energetic fluorine species.
According to a first aspect of the present invention there is provided a method for producing alkali metal fluorohalate, preferably tetrafluorohalate, comprising the direct fluorination of one or more alkali metal halides.
Preferably only one alkali metal halide is employed. Preferably a potassium form is used.
The halate is preferably provided in the chlorate form, although the iodate or bromate forms may be used.
KCl is a preferred starting material, most preferably according to the reaction : -
KCl + 2F2 KC1F4
Preferably the reaction is carried out at temperatures in the range of 15 to 250°C and most preferably 90 to 250°C. The reaction temperature, and preferably the maximium reaction temperature, may be between 190 to 325 °C, and more preferably may be between 220 and 270°C.
The reaction is preferably carried out in a vacuum system which excludes air and moisture. By vacuum system is meant a high pressure system capable of being evacuated to remove moisture and/or air.
The fluorine may be provided at elevated pressure. Preferably at least the inital, fluorine pressure is between 1 and 10 atm, and more preferably between 2.5 and 5 atm.
The reaction is preferably carried out for a time period of at least 60 minutes, and more preferably a time period of between 80 and 400 minutes.
The fluorine may be scrubbed with sodium fluoride prior to the reaction to remove HF . Alternatively or additionally a cold trap, for instance at less than -70°C, may be employed. The complete removal of HF from the fluorine is desirable .
The intermediate may be formed as a transitional state in the production of active fluorine or as an intermediate form for transportation and/or storage, preferably prior to conversion to active fluorine.
The reaction products may be purified prior to storage.
The alkali metal tetrafluorohalate is preferably provided in pellet form.
The alkali metal tetrafluorohalate may be RbClF4 or CsClF4 or any other suitable alkali metal. The form may be used as a solid suitable for transportation. KCIF4 is particularly preferred.
Preferably the active fluorine is produced from the alkali metal tetrafluorohalate by thermal decomposition.
The active fluorine may be or include one or more of XFn, where X is Cl, Br or I , and n is 1, 3, 5 or 7.
According to a second aspect of the invention we provide the use of alkali metal flurohalate, preferably tetrafluorohalate, or active fluorine produced from alkali metal fluorohalate, preferably tetrafluorohalate, produced according to the method of the first aspect.
The use of the active fluorine sources may be in cleaning or etching semi-conductor materials or apparatus or equipment involved in their production and processing.
According to a third aspect of the invention we claim the use of alkali metal fluorohalate, preferably tetrafluorohalate, produced according to the first aspect of the invention, as a transportable and/or storable source of active fluorine.
The invention will now be described in detail, by way of example only.
In order to produce the solid alkali metal tetrafluorochlorate for the transportation and storage of active fluorine in the desired way it is necessary to prepare a solid alkali metal tetrafluorochlorate, such as KC1F4.
Production in a first embodiment is provided by the fluorination of alkali chlorides according to the general reaction : -
MCI + 2F2 MC1F4 where M is an alkali metal .
The fluorination is carried out at between 15-300°C and yields a dense melt. Temperatures of 90-200°C are appropriate to the potassium and caesium forms. The exclusion of water from the reaction vessel is important for obtaining the correct products .
EXAMPLE 1
A nickel reaction vessel was charged with KCl (0.31g, 0.0042mols) at room temperature. Still at room temperature, the vessel was charged with F2 (2.86atm, 0.012mol) giving rise to an exothermic reaction almost instantly.
The system was then heated to a maximium of 263°C over a period of 90 minutes, before being allowed to cool.
The percentage yield of KC1F4 obtained, based on the change in pressure of the fluorine gas, was determined at 81%. Heating the resulting solid KC1F4 to 220°C for 90 minutes produced active fluorine.
EXAMPLES 2 TO 5
Additional tests under the conditions set out below, in closed systems, gave the following results :-
MASS OF PRESSURE MAXIMIUM REACTION %
KCl OF F2 REACTION TIME YIELD
(grams) (atm) TEMP (°C) (mins) KC1F4
0.2810 3.45 257 145 84
0.2680 3.50 256 300 85
0.2684 3.49 228 90 75
0.2756 3.35 246 150 73
By allowing the reaction products to cool prior to separation the intermediary itself, in the examples KC1F4, can be obtained. By removing the reaction products before cooling the desired active fluorine species are obtained.

Claims

1. A method of producing active fluorine in which one or more alkali metal halides are directly fluorinated to produce alkali metal fluorohalate, the alkali metal fluorohalate being decomposed to produce active fluorine.
2. A method for producing alkali metal fluorohalate, preferably tetrafluorohalate, comprising the direct fluorination of one or more alkali metal halides, and wherein the maximium reaction temperature is between 230 and 260°C, the fluorine pressure is initally between 2.5 and 5 atm and the reaction is carried out for a period of between 80 and 300 minutes.
3. The method of claim 1 or claim 2 in which the alkali metal halide is KCl.
4. The method of any of claims 1 to 3 in which the reaction is carried out at temperatures in the range of 90 to 250°C.
5. The method of any of claims 1 to 4 in which the maximium reaction temperature is between 190 to 325°C.
6. The method of any of claims 1 to 5 in which the reaction is carried out in a vacuum system which excludes air and moisture .
7. The method of any of claims 1 to 5 in which the fluorine is provided at elevated pressure, preferably, at least the inital, fluorine pressure is between 2.5 and 5 atm.
8. The method of any of claims 1 to 6 in which the reaction is carried out for a time period of at least 60 minutes, and more preferably a time period of between 80 and 400 minutes.
9. The method of any of claims 1 to 7 in which the fluorine is scrubbed with sodium fluoride prior to the reaction to remove HF.
10. The method of any of claims 1 to 9 in which the alkali metal fluorohalate intermediate is formed as a transitional state in the production of active fluorine.
11. The method of any of claims 1 to 9 in which the alkali metal fluorohalate intermediate is formed as an intermediate form for transportation and/or storage, prior to conversion to active fluorine .
12. The method of claim 11 in which the reaction products are RbClF4 or CsClF4 or KCIF4.
13. The use of active fluorine produced from alkali metal fluorohalate produced according to the method of any of claims 1 to 12 for cleaning and/or etching materials.
14. The use of alkali metal fluorohalate, produced according to the method of any of claims 1 to 12, as a transportable and/or storable source of active fluorine.
PCT/GB1997/003348 1996-12-19 1997-12-16 Process for the production of active fluorine and intermediates involved in active fluorine production and use of this active fluorine Ceased WO1998027006A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU77379/98A AU7737998A (en) 1996-12-19 1997-12-16 Process for the production of active fluorine and intermediates invol ved in active fluorine production and use of this active fluorine

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GBGB9626318.1A GB9626318D0 (en) 1996-12-19 1996-12-19 Improvements in and relating to the production of active fluorine
GB9626318.1 1996-12-19

Publications (1)

Publication Number Publication Date
WO1998027006A1 true WO1998027006A1 (en) 1998-06-25

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PCT/GB1997/003348 Ceased WO1998027006A1 (en) 1996-12-19 1997-12-16 Process for the production of active fluorine and intermediates involved in active fluorine production and use of this active fluorine

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AU (1) AU7737998A (en)
GB (1) GB9626318D0 (en)
WO (1) WO1998027006A1 (en)
ZA (1) ZA9711442B (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2012016997A1 (en) * 2010-08-05 2012-02-09 Solvay Sa Method for the purification of fluorine

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3143391A (en) * 1959-10-12 1964-08-04 Olin Mathieson Alkali metal tetrafluorochlorates and their preparation
US3361543A (en) * 1963-04-01 1968-01-02 Monsanto Res Corp Synthesis of alkali metal tetrafluorochlorates
US3989808A (en) * 1975-07-28 1976-11-02 The United States Of America As Represented By The United States Energy Research And Development Administration Method of preparing pure fluorine gas
US4284617A (en) * 1979-11-30 1981-08-18 The United States Of America As Represented By The Secretary Of The Navy Solid compositions for generation fluorine and gaseous fluorine compounds

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3143391A (en) * 1959-10-12 1964-08-04 Olin Mathieson Alkali metal tetrafluorochlorates and their preparation
US3361543A (en) * 1963-04-01 1968-01-02 Monsanto Res Corp Synthesis of alkali metal tetrafluorochlorates
US3989808A (en) * 1975-07-28 1976-11-02 The United States Of America As Represented By The United States Energy Research And Development Administration Method of preparing pure fluorine gas
US4284617A (en) * 1979-11-30 1981-08-18 The United States Of America As Represented By The Secretary Of The Navy Solid compositions for generation fluorine and gaseous fluorine compounds

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
CHEMICAL ABSTRACTS, vol. 85, no. 12, 20 September 1976, Columbus, Ohio, US; abstract no. 80474, FOGLE, C. E. ET AL: "Solid reactants for fluorine gas generators" XP002062746 *
U. S. NTIS, AD REP. (1976), AD-A022099, 112 PP. AVAIL.: NTIS FROM: GOV. REP. ANNOUNCE. INDEX (U. S.) 1976, 76(10), 211 CODEN: XADRCH, 1976 *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2012016997A1 (en) * 2010-08-05 2012-02-09 Solvay Sa Method for the purification of fluorine
US8821821B2 (en) 2010-08-05 2014-09-02 Solvay Sa Method for the purification of fluorine

Also Published As

Publication number Publication date
ZA9711442B (en) 1999-06-21
AU7737998A (en) 1998-07-15
GB9626318D0 (en) 1997-02-05

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