CA1041035A - Process for the electrochemical fluorination of organic acid halides - Google Patents
Process for the electrochemical fluorination of organic acid halidesInfo
- Publication number
- CA1041035A CA1041035A CA208,756A CA208756A CA1041035A CA 1041035 A CA1041035 A CA 1041035A CA 208756 A CA208756 A CA 208756A CA 1041035 A CA1041035 A CA 1041035A
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- CA
- Canada
- Prior art keywords
- process according
- acid halides
- electrolyte
- fluorination
- organic acid
- Prior art date
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B3/00—Electrolytic production of organic compounds
- C25B3/20—Processes
- C25B3/27—Halogenation
- C25B3/28—Fluorination
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)
Abstract
Process for the electrochemical fluorination of organic acid halides Abstract of the Disclosure A process for the electrochemical fluorination of organic acid halides is provided. The electrochemical process is carried out in liquid hydrogen fluoride as electrolyte containing 5 to 20 percent by weight based on the electrolyte of the acid halide, at temperatures of 20 to 50°C, optionally under pressure and at a cell voltage of 9 to 15, preferably of 9 to 13 volts direct current. The anodes used are of nickel or a nickel alloy while the cathodes are e.g. of iron or steel and the distance between the electrodes is about 6 to 12 mm. According to this process perfluorinated compounds of high purity and in good yields are obtained. These compounds are useful as surfactants or as intermediates for the manufacture of surfactants, oil- and water-repellents lubricants and the like.
Description
0~5 Processes for the mallufacture of fluorocarbon compo~mds are al eady known. US paten~ 2,519,983 doscribes t~e electro-chemical manu~acture of fluorocarbon compounds at a cell . . . ~ , , .
voltage of about 4 to ~ volts direct current, a current densi~ of up to about 20 m ~/cm2 and at a temperature of-20C to ~0C, prefera~ly 0C to ~20 C, in liquid hydrogen fluoride as ; electrolyte The application of a higher voltage is not re-co~nended since energy is lost a~d at the same time no im-provement in yield is attained. Further, long-chain carbon A compounds are more b~gb~ fragmented simulta~eously with the , : .
addition of fluorine, i.e a great number of compounds with a ; lower number of car~on atoms than those of the starting compound are formed. The electrochemical fluorination of carboxylic acid halides and sulphonic acid halides forms the subject matter of US patents 2,717,871 and 2,732,398. The conditions for carry-ing out the process correspond to the state~ values, i.e. the ; process is carried out for example at a cell voltage of about 4 to 6 volts direct current. Likewise only unsatisfactory yields are obtained with long-chain starting products, since molecular fragmentation~ optionally combined with cyclisation reactions, occur during the reaction. Consequently, the yields of tri-; fluoromethanesulphochloride are about 55 % (T. Gramstead and R.N. Hazeldine, J.C.S. 173 (1956) report 96 %) and of perfluoro-octanesu'phochloride 25 % [cf. T,Gra~stead and R.N. Hazeldine, , 25 J.C.S. 2640 (1957)], whereas J.Burdon et al., J.C.S. 2574 (1957) ~`~ obtain only about 12 % to 15 %.
.'' , ' ' ' ~: ' ', o~s A further process for the electrochemical fluorination is known from German Auslegeschrift 1468284. By the choice of the starting compounds, the attempt is made to improve both the selectivity of the ; electrochemical reaction and the yield. The process, which is carried out under the cited conditions (potential of about 4 to 8 volts), is confined to a special group of starting compounds some of which are not readily accessible. The yields are only good in respect of short-chain molecules, whereas e.g. in the manufacture of C8Fl7S02F only yields of less than 20%
were obtained.
The present invention provides an improvement of the process for the electrochemical fluorination of organic acid halides, in particular of long-chain acid halides, by using - in contrast to the prior art - a : substantially higher cell voltage while at the same time optionally increas-ing the current density. The temperature range for carrying out the : electrochemical fluorination has also been modified. Surprisingly, the - yield of fluorinated acid halides and the purity of the end products are substantially improved in the process according to the invention while at the same time improving the current yield. The formation of molecular fragments with fewer carbon atoms than the starting material, the occurrence ~' 20 of any side reactions and the formation of only partially fluorinated , products can be very largely avoided. Further, the corrosion of the anode material is materially reduced.
The present invention therefore provides a process for the electrochemical fluorination of alkylcarboxylic acid halides or alkyl- -~
sulphonic acid halides of 5 to 18 carbon atoms using an anode of nickel or a nickel alloy, a metal cathode and liquid hydrogen fluoride as electrolyte, which comprises electrolysing the organic acid halides in an amount of 5 to .
' ' .~ - 3 ~
'`.'' ~: -: .
- ~4~ S
20 percent by weight, based on the electrolyte, at temperatures of 20C to ; 50C, and at a cell voltage of 9 to 15 volts direct current, the distance between the electrodes being 6 to 12 mm, and subsequently separating the fluorinated products from the electrolyte.
Suitable organic acid halides are normally alkylcarboxylic ~ acid and alkylsulphonic acid halides with 5 to 18, preferably 6 to 12 or ; 8 to 10, carbon atoms in the alkyl moiety. Acid chlorides and, in particular, acid fluorides are preferred. They have e.g. the formulae : ' (1) 3 ( 2)m and
voltage of about 4 to ~ volts direct current, a current densi~ of up to about 20 m ~/cm2 and at a temperature of-20C to ~0C, prefera~ly 0C to ~20 C, in liquid hydrogen fluoride as ; electrolyte The application of a higher voltage is not re-co~nended since energy is lost a~d at the same time no im-provement in yield is attained. Further, long-chain carbon A compounds are more b~gb~ fragmented simulta~eously with the , : .
addition of fluorine, i.e a great number of compounds with a ; lower number of car~on atoms than those of the starting compound are formed. The electrochemical fluorination of carboxylic acid halides and sulphonic acid halides forms the subject matter of US patents 2,717,871 and 2,732,398. The conditions for carry-ing out the process correspond to the state~ values, i.e. the ; process is carried out for example at a cell voltage of about 4 to 6 volts direct current. Likewise only unsatisfactory yields are obtained with long-chain starting products, since molecular fragmentation~ optionally combined with cyclisation reactions, occur during the reaction. Consequently, the yields of tri-; fluoromethanesulphochloride are about 55 % (T. Gramstead and R.N. Hazeldine, J.C.S. 173 (1956) report 96 %) and of perfluoro-octanesu'phochloride 25 % [cf. T,Gra~stead and R.N. Hazeldine, , 25 J.C.S. 2640 (1957)], whereas J.Burdon et al., J.C.S. 2574 (1957) ~`~ obtain only about 12 % to 15 %.
.'' , ' ' ' ~: ' ', o~s A further process for the electrochemical fluorination is known from German Auslegeschrift 1468284. By the choice of the starting compounds, the attempt is made to improve both the selectivity of the ; electrochemical reaction and the yield. The process, which is carried out under the cited conditions (potential of about 4 to 8 volts), is confined to a special group of starting compounds some of which are not readily accessible. The yields are only good in respect of short-chain molecules, whereas e.g. in the manufacture of C8Fl7S02F only yields of less than 20%
were obtained.
The present invention provides an improvement of the process for the electrochemical fluorination of organic acid halides, in particular of long-chain acid halides, by using - in contrast to the prior art - a : substantially higher cell voltage while at the same time optionally increas-ing the current density. The temperature range for carrying out the : electrochemical fluorination has also been modified. Surprisingly, the - yield of fluorinated acid halides and the purity of the end products are substantially improved in the process according to the invention while at the same time improving the current yield. The formation of molecular fragments with fewer carbon atoms than the starting material, the occurrence ~' 20 of any side reactions and the formation of only partially fluorinated , products can be very largely avoided. Further, the corrosion of the anode material is materially reduced.
The present invention therefore provides a process for the electrochemical fluorination of alkylcarboxylic acid halides or alkyl- -~
sulphonic acid halides of 5 to 18 carbon atoms using an anode of nickel or a nickel alloy, a metal cathode and liquid hydrogen fluoride as electrolyte, which comprises electrolysing the organic acid halides in an amount of 5 to .
' ' .~ - 3 ~
'`.'' ~: -: .
- ~4~ S
20 percent by weight, based on the electrolyte, at temperatures of 20C to ; 50C, and at a cell voltage of 9 to 15 volts direct current, the distance between the electrodes being 6 to 12 mm, and subsequently separating the fluorinated products from the electrolyte.
Suitable organic acid halides are normally alkylcarboxylic ~ acid and alkylsulphonic acid halides with 5 to 18, preferably 6 to 12 or ; 8 to 10, carbon atoms in the alkyl moiety. Acid chlorides and, in particular, acid fluorides are preferred. They have e.g. the formulae : ' (1) 3 ( 2)m and
(2) 3 ( 2)n 2 ' ., ` wherein X represents fluorine, chlorine or bromine, m is an integer from 3 to 16, preferably from 4 to 10 or 6 to 8, and n is an integer from 4 to - 17, preferably from 5 to 11 or 7 to 9. Preferred acid fluorides are also those of the formulae '
3 2 m and ( ) CH3 (CH2)n S02F, .....
~, wherein m is an integer from 4 to 10, preferably 6 to 8, and n is an integer from 5 to 11, preferably from 7 to 9.
''' , lf~ S
Examples o organic acid halides are hexanoic-, octanoic-, decanoic- or ~odecano;icsulpl~oni_ acid halides, in par~icular . ~he sulphonic acid fluorides.
These acid halides are mixed with the liquid hydrogen fluoride in an amount of about 5 to 20, preferably 5 to 15 or 10 to 15 % by wei~ht before the start of the eLectrochemical fluorination. Col~nercial anhydrous liquid hydrogen fluoride : which normally contains a trace of water is used as electrolyte.
- In contact with a humid atmosphere, the hydrogen fluoride moreover takes up water. The bulk of this water can be removed r~ ~ by a preliminary electrolysis that is carried out before addi-j. .
tion of the starting materials. The water is removed by hydrogen, ; oxygen and oxygen fluoride (OF2), all of which escape in gaseous .
form.It is not necessary to add conductivity salts. e.g. potas-:r ~ 15 sium fluoride, to the electrolyte, since this causes increased . . .
corrosion of the electrode material. Moreover, the el-ectrolyte retains its conductivity, even after termination of the ~;~
fluorination, so that the conclusion of the reaction is only inadequately detected. ;
The electrochemical fluorination is carried out at tem-peratures between 20 C and 50CJ preferably between 30 C and ~0 C. The best yields are obtained at about 30C to 35 C. The process is ordinarily carried out at normal pressure or at an - overpressure of up to about 5 ba~,preferably up to about 1 bar.
The cell voltage is 9 to 15, preferably 9 to 13 or 9 to 12 volts willtout any dev~lopment of fluorine gas being observ-. . _ 5 _ . , :
. . ~-, .
'''':' ' , ', ., ', ' .-, . ~-, ' - . ... ~ . "' ':
- , . . . . , .. ~ , ., -
~, wherein m is an integer from 4 to 10, preferably 6 to 8, and n is an integer from 5 to 11, preferably from 7 to 9.
''' , lf~ S
Examples o organic acid halides are hexanoic-, octanoic-, decanoic- or ~odecano;icsulpl~oni_ acid halides, in par~icular . ~he sulphonic acid fluorides.
These acid halides are mixed with the liquid hydrogen fluoride in an amount of about 5 to 20, preferably 5 to 15 or 10 to 15 % by wei~ht before the start of the eLectrochemical fluorination. Col~nercial anhydrous liquid hydrogen fluoride : which normally contains a trace of water is used as electrolyte.
- In contact with a humid atmosphere, the hydrogen fluoride moreover takes up water. The bulk of this water can be removed r~ ~ by a preliminary electrolysis that is carried out before addi-j. .
tion of the starting materials. The water is removed by hydrogen, ; oxygen and oxygen fluoride (OF2), all of which escape in gaseous .
form.It is not necessary to add conductivity salts. e.g. potas-:r ~ 15 sium fluoride, to the electrolyte, since this causes increased . . .
corrosion of the electrode material. Moreover, the el-ectrolyte retains its conductivity, even after termination of the ~;~
fluorination, so that the conclusion of the reaction is only inadequately detected. ;
The electrochemical fluorination is carried out at tem-peratures between 20 C and 50CJ preferably between 30 C and ~0 C. The best yields are obtained at about 30C to 35 C. The process is ordinarily carried out at normal pressure or at an - overpressure of up to about 5 ba~,preferably up to about 1 bar.
The cell voltage is 9 to 15, preferably 9 to 13 or 9 to 12 volts willtout any dev~lopment of fluorine gas being observ-. . _ 5 _ . , :
. . ~-, .
'''':' ' , ', ., ', ' .-, . ~-, ' - . ... ~ . "' ':
- , . . . . , .. ~ , ., -
4~ S
ed. The ~oltage theoretlcally necessary or the manufacture of free fluor:ine (~2) from hydrogen fluoride is about 3 volts (US patent 2,S19,9~3~. Lf it is possible to apply higher voltages without the development of fluorine gas according, the reason is that a substantial amount of the voltage is used up for overcoming the resistances that are formed through the electrolyte, the ele~trodes and especially througll polarisation , . .
effects at the electrode surfaces.
The electrodes are spacecl about 6 to 12,pre~erably 8 to 10 mm apart. These relatively large spacings made it possible ... .
. ..................................................................... .
for example to markedly reduce the corrosion of the electrodes and the danger of a short-circuit reaction between the electrodes.
The current densities can be in the approximate range A from 10 to lO0 ffl-A/cm2, preferably in the range from 20 to 60~/cm , whereby it is possible to attain current ~; yields of over 50 %. Although the reaction mechanism has not ~,,,;,. . .
been fully clarified and the present invention is not limited by any specific reaction mechanism, it is assumed that in the electrochemical fluorination described herein a loose, active complex of different nickel fluorides and molecular or atomic fluorine is first formed at the anode. The acid halide adsorbed on the com~lex is then com~letely reacted, then the current densitiy falls to a fraction of the initial value and thereby - indicates the end of the electrochemical fl~orination.
Support for this possible reaction mechanism is to be found in the fact that practically no partially fluorinated . " :
.'.. ': ..
. ~ ' .
U~S
prGducts are formed and that there is no visible formation of flt~oline gas, since free fluorine (F2) from the active complex carl also be used for the fluorin~tion. It can further ., .: .
be observed that the corrosion of the anodes (ater an in-duction period using new anodes) is very slight, which can be a~trib-uted to the formation of a protective layer of nickel , fluorides.
Preferably nickel or a nickel alloy is used as anode :~ .
material for the process according to the invention;but 10 optionally it is also possible to use anodes of silicon carbide or charcoal. Suitable cathodes are iron or steel cathodes, also those of e.g. aluminium~ copper, nickel or ;~
.~. .
nickel alloys.
. ~ ~
- The electrochemical fluorination can be carried out ;
batchwise and optionally also semibatchwise by replenishing both the organic compo~md and the hydrogen fluoride electroly~e from time to time in the same amount in which they are used up and separating the perfluorinated products which are insoluble ~ in hydrogen fluoride from the electrolyte and removing them - 20 from the cell.
The escaping gas mixture can be led through an ascending `
coole~ in order to condense the hydrogen fluoride vapours, then after dilution with an inert gas it is absorbed in dilute sodi~m hydroxide solution.
The perfluorinated compounds obtained are valuable ;~
starting materials for the manufacture of oil and water re-.:' ' ''"
: , .. . .
'~ ' , , ' :
: , , ;~ , 1(~4~
pellents, sur.EacLants, lubricants and the like. The end produc~s are obtai.ned by modification the acid halidc gro~lping b~ kno~
chemic~ reac~ions. Further, they can also be used by themselves .~. as surfactants.
The following Examples describe the.invention ir. more `.~ detail but do not limit it to what is described therein.
;' ' ' :, ' ;
.'.
.'".' .
' ~ .
.,~ .
.:' .
. . .... .
1~ 5 -'; Example ]
_ ~ufacture o~ f orc)oc~yls~ c _cid fluoride The reaction is carried out in a~ electrolysis cell of nickel with a capacity for 40 ml of liquid hydrogen fluoride and provided with a nickel anode (0.35 dm surface area), a thermometer, an inlet pipe for ~he acid halide and the liquid hydrogen ~]uoride as well as an exhaust gas pipe cooled to -15C
which is sparged with nitrogen in order to prevent the formatio - of explosive gas mixtures and to produce a desired pressure ,~
(under which the electrochemical reaction proceeds) in the ~, cell. The cell is in a thermostat. ~t the start of the reaction, the cell is cooled to -~10 C, then the liquid hydrogen fluo~ide (-10C) and octanesulphonic acid fluoride are charged into the c-eil.
, The cell is then heated with thethermostat to the desired temperature. The nitrogen pressure is about 0.6 bar overpressure at 35 C. Upon termination of the reaction, the cell is again ' ~' conled to a temperature of ~10 C and brought to normal pressure. ;`
~` The fluorinated reaction product is insoluble in liquid hydrogen .:
,'~` 20 fluoride and precipitates as a colourless oil on the bottom of the cell. The oil is isolated and washed with 10 % aqueous ;"
sodium hydrogen carbonate solution. Thepurity of the product is normally 90 to 95 % (analysis by gas chromatography)~ The .- . :.,- .
indicated yields are calculated on the oily end product with a '' content of at least 90 % per-fluorooctylsulphonic acid fluoride.
, The following table contains the test conditions and results:
;~ ,, ' .:. -': . . .
_ g ~
~' . ' ' "'.''-.: .
. . . ' ' .
...... . . . . .. .. .. ..
- . : . . . :. , : :
3 ~41()35 ":
~._ _ ,, ~
e~periment l 2 3 4 5 6 (comp ri~so~i~
:: ~ ~ ~ _.--; ten-perature ( C) 32 34 32 30 32 20 . _ . __ . _. .. ,.. __ _ amoun~ by octane-l . suLpllo~uoride ~1 4 4 4 4 4 4 : ~_ _ ..... ~ . . __ ___ .
concentration . in % 10 10 10 ]S 10 10 : ~relative to the l -electrolyte~ .
. " _ _~
~; potential volt 1 9 9 10.5 ].2 12 7 - A cUrrent densi~y ~.025 .. 0~.020 . 0~050 0~056 0~056 0~.01 cCoun~ru~nlpttion~ ~ .6 lS.6 18.6 18.6 18.6 18.6 (theoret.) ... _ , ... . . ._~
current I ' consumptiOn Ah ~15 16 1-2 13 13 20 ~4~ (actual) ~
. .. .. ~ . . ._ __ ..... . . _ _ ~_ current ~. . .
. consump~ion re- 81. 86 65 70 70 llO -: ferred ~o tne tl~eo ~. .
retical va~ue (%) :: ~ ...... ~
current yield (%~ 50 50 72 87 81 27 .; . _ ........ : . .___ __ , product yield (~) ¦ 3~4 3~.6 3~9 5~ 8 prod~ct yield (%) ¦ 4l 43 ~7 6] 57 30 .. .
:. - 1 0 -.
., . . .
i(135 ., .
Experimenk ~ was carried out under the conditions of ~he . prior ar-k. The yield obtainecl is markedly lower than the yields ; that are obtained with tlle process according to the invention.
.
Example 2 Perfluor~ ation of n-heptane-l-car~o~rlic acid fluoricle .... . _ (octanoic fluoridc) ~
. .
At 0C, 20 parts of anhydrous hydrogen fluoride are charged into the electrolysis cell according to Example l and then 3 parts of n-heptane-l-carboxylic acid fluoride are added thereto. The contenks are electrolysed under a nitrogen over-pressure of 1 bar at 30Cj a cell voltage of lO volts and an initial current density of 0.037 A/cm . The electrolysis is - discontinued when 80 % of the theoretical amount of current has been consumed.
, 15 Yield: 2.65 parts of a crude oil with 87 V/~ content of -perfluorinated compound. The oil is purified as described in ;;
Example 1. The yield is 37 a/a of theory.
.. ..
., ! .
: .
.. . .
.'`, ''; ;.~ ' -.
'. .':~ ~
:' ` .~ :
. , ~:
' ' '`'. :
.. ,: - 11 - . ~.
~ . .
, ' ' ' :-' .. ,. . . - - ' ~ :
ed. The ~oltage theoretlcally necessary or the manufacture of free fluor:ine (~2) from hydrogen fluoride is about 3 volts (US patent 2,S19,9~3~. Lf it is possible to apply higher voltages without the development of fluorine gas according, the reason is that a substantial amount of the voltage is used up for overcoming the resistances that are formed through the electrolyte, the ele~trodes and especially througll polarisation , . .
effects at the electrode surfaces.
The electrodes are spacecl about 6 to 12,pre~erably 8 to 10 mm apart. These relatively large spacings made it possible ... .
. ..................................................................... .
for example to markedly reduce the corrosion of the electrodes and the danger of a short-circuit reaction between the electrodes.
The current densities can be in the approximate range A from 10 to lO0 ffl-A/cm2, preferably in the range from 20 to 60~/cm , whereby it is possible to attain current ~; yields of over 50 %. Although the reaction mechanism has not ~,,,;,. . .
been fully clarified and the present invention is not limited by any specific reaction mechanism, it is assumed that in the electrochemical fluorination described herein a loose, active complex of different nickel fluorides and molecular or atomic fluorine is first formed at the anode. The acid halide adsorbed on the com~lex is then com~letely reacted, then the current densitiy falls to a fraction of the initial value and thereby - indicates the end of the electrochemical fl~orination.
Support for this possible reaction mechanism is to be found in the fact that practically no partially fluorinated . " :
.'.. ': ..
. ~ ' .
U~S
prGducts are formed and that there is no visible formation of flt~oline gas, since free fluorine (F2) from the active complex carl also be used for the fluorin~tion. It can further ., .: .
be observed that the corrosion of the anodes (ater an in-duction period using new anodes) is very slight, which can be a~trib-uted to the formation of a protective layer of nickel , fluorides.
Preferably nickel or a nickel alloy is used as anode :~ .
material for the process according to the invention;but 10 optionally it is also possible to use anodes of silicon carbide or charcoal. Suitable cathodes are iron or steel cathodes, also those of e.g. aluminium~ copper, nickel or ;~
.~. .
nickel alloys.
. ~ ~
- The electrochemical fluorination can be carried out ;
batchwise and optionally also semibatchwise by replenishing both the organic compo~md and the hydrogen fluoride electroly~e from time to time in the same amount in which they are used up and separating the perfluorinated products which are insoluble ~ in hydrogen fluoride from the electrolyte and removing them - 20 from the cell.
The escaping gas mixture can be led through an ascending `
coole~ in order to condense the hydrogen fluoride vapours, then after dilution with an inert gas it is absorbed in dilute sodi~m hydroxide solution.
The perfluorinated compounds obtained are valuable ;~
starting materials for the manufacture of oil and water re-.:' ' ''"
: , .. . .
'~ ' , , ' :
: , , ;~ , 1(~4~
pellents, sur.EacLants, lubricants and the like. The end produc~s are obtai.ned by modification the acid halidc gro~lping b~ kno~
chemic~ reac~ions. Further, they can also be used by themselves .~. as surfactants.
The following Examples describe the.invention ir. more `.~ detail but do not limit it to what is described therein.
;' ' ' :, ' ;
.'.
.'".' .
' ~ .
.,~ .
.:' .
. . .... .
1~ 5 -'; Example ]
_ ~ufacture o~ f orc)oc~yls~ c _cid fluoride The reaction is carried out in a~ electrolysis cell of nickel with a capacity for 40 ml of liquid hydrogen fluoride and provided with a nickel anode (0.35 dm surface area), a thermometer, an inlet pipe for ~he acid halide and the liquid hydrogen ~]uoride as well as an exhaust gas pipe cooled to -15C
which is sparged with nitrogen in order to prevent the formatio - of explosive gas mixtures and to produce a desired pressure ,~
(under which the electrochemical reaction proceeds) in the ~, cell. The cell is in a thermostat. ~t the start of the reaction, the cell is cooled to -~10 C, then the liquid hydrogen fluo~ide (-10C) and octanesulphonic acid fluoride are charged into the c-eil.
, The cell is then heated with thethermostat to the desired temperature. The nitrogen pressure is about 0.6 bar overpressure at 35 C. Upon termination of the reaction, the cell is again ' ~' conled to a temperature of ~10 C and brought to normal pressure. ;`
~` The fluorinated reaction product is insoluble in liquid hydrogen .:
,'~` 20 fluoride and precipitates as a colourless oil on the bottom of the cell. The oil is isolated and washed with 10 % aqueous ;"
sodium hydrogen carbonate solution. Thepurity of the product is normally 90 to 95 % (analysis by gas chromatography)~ The .- . :.,- .
indicated yields are calculated on the oily end product with a '' content of at least 90 % per-fluorooctylsulphonic acid fluoride.
, The following table contains the test conditions and results:
;~ ,, ' .:. -': . . .
_ g ~
~' . ' ' "'.''-.: .
. . . ' ' .
...... . . . . .. .. .. ..
- . : . . . :. , : :
3 ~41()35 ":
~._ _ ,, ~
e~periment l 2 3 4 5 6 (comp ri~so~i~
:: ~ ~ ~ _.--; ten-perature ( C) 32 34 32 30 32 20 . _ . __ . _. .. ,.. __ _ amoun~ by octane-l . suLpllo~uoride ~1 4 4 4 4 4 4 : ~_ _ ..... ~ . . __ ___ .
concentration . in % 10 10 10 ]S 10 10 : ~relative to the l -electrolyte~ .
. " _ _~
~; potential volt 1 9 9 10.5 ].2 12 7 - A cUrrent densi~y ~.025 .. 0~.020 . 0~050 0~056 0~056 0~.01 cCoun~ru~nlpttion~ ~ .6 lS.6 18.6 18.6 18.6 18.6 (theoret.) ... _ , ... . . ._~
current I ' consumptiOn Ah ~15 16 1-2 13 13 20 ~4~ (actual) ~
. .. .. ~ . . ._ __ ..... . . _ _ ~_ current ~. . .
. consump~ion re- 81. 86 65 70 70 llO -: ferred ~o tne tl~eo ~. .
retical va~ue (%) :: ~ ...... ~
current yield (%~ 50 50 72 87 81 27 .; . _ ........ : . .___ __ , product yield (~) ¦ 3~4 3~.6 3~9 5~ 8 prod~ct yield (%) ¦ 4l 43 ~7 6] 57 30 .. .
:. - 1 0 -.
., . . .
i(135 ., .
Experimenk ~ was carried out under the conditions of ~he . prior ar-k. The yield obtainecl is markedly lower than the yields ; that are obtained with tlle process according to the invention.
.
Example 2 Perfluor~ ation of n-heptane-l-car~o~rlic acid fluoricle .... . _ (octanoic fluoridc) ~
. .
At 0C, 20 parts of anhydrous hydrogen fluoride are charged into the electrolysis cell according to Example l and then 3 parts of n-heptane-l-carboxylic acid fluoride are added thereto. The contenks are electrolysed under a nitrogen over-pressure of 1 bar at 30Cj a cell voltage of lO volts and an initial current density of 0.037 A/cm . The electrolysis is - discontinued when 80 % of the theoretical amount of current has been consumed.
, 15 Yield: 2.65 parts of a crude oil with 87 V/~ content of -perfluorinated compound. The oil is purified as described in ;;
Example 1. The yield is 37 a/a of theory.
.. ..
., ! .
: .
.. . .
.'`, ''; ;.~ ' -.
'. .':~ ~
:' ` .~ :
. , ~:
' ' '`'. :
.. ,: - 11 - . ~.
~ . .
, ' ' ' :-' .. ,. . . - - ' ~ :
Claims (15)
1. A process for the electrochemical fluorination of alkylcarboxylic acid halides or alkylsulphonic acid halides of 5 to 18 carbon atoms using an anode of nickel or a nickel alloy, a metal cathode and liquid hydrogen fluoride as electrolyte, which comprises electrolysing the organic acid halides in an amount of 5 to 20 percent by weight, based on the electrolyte, at temperatures of 20° C to 50° C, and at a cell voltage of 9 to 15 volts direct current, the distance between the electrodes being 6 to 12 mm, and subsequently separating the fluorinated products from the electrolyte.
2. A process according to claim 1, wherein the organic acid halides are electrolysed at temperatures of 20° C to 50° C under pressure.
3. A process according to claim 1, which comprises electrolysing organic acid halides of the formulae CH3 (CH2)m COX and CH3 (CH2)n SO2X , wherein X represents fluorine, chlorine or bromine, m is an integer from 3 to 16 and n is an integer from 4 to 17, in an amount of 5 to 20 percent by weight, based on the electrolyte, at temperatures of 20° C to 50° C and at a cell voltage of 9 to 15 volts direct current, the distance between the electrodes being 6 to 12 mm, and subsequently separating the fluorinated products from the electrolyte.
4. A process according to claim 3, wherein the organic acid halides are electrolysed at temperatures of 20° C to 50° C under pressure.
5. A process according to claim 3, wherein the acid halides are acid fluorides of the formulae CH3 (CH2)m COF and CH3 (CH2)n SO2F
wherein m is 4 to 10, preferably 6 to 8, and n is 5 to 11, preferably 7 to 9.
wherein m is 4 to 10, preferably 6 to 8, and n is 5 to 11, preferably 7 to 9.
6. A process according to claim 3, wherein the distance between the electrodes is 8 to 10 mm.
7. A process according to either of claims 1 or 3, wherein the amount of the acid halides is 5 to 15, preferably 10 to 15 percent by weight, based on the electrolyte.
8. A process according to any one of claims 1 and 3, wherein the fluorination is carried out at temperatures of 30° C to 40° C, preferably at 30° C to 35° C.
9. A process according to any one of claims 1 and 3, wherein the fluorination is carried out at a cell voltage of 9 to 13 volts.
10. A process according to any one of claims 1 and 3, wherein the fluorination is carried out at a cell voltage of 9 to 12 volts.
11. A process according to claim 2, wherein the fluorination is carried out at an overpressure of up to about 5 bar.
12. A process according to claim 4, wherein the fluorination is carried out at an overpressure of up to about 5 bar.
13. A process according to any one of claims 11 and 12, wherein the fluorination is carried out at an over-pressure of up to 1 bar.
14. A process according to claim 5, wherein the acid fluorides are octanesulphonic fluoride or octanoic fluoride.
15. A process according to any one of claims 1 and 3, which comprises adding the organic acid halides to the electrolyte semibatchwise and separating the insoluble perfluorinated products from the electrolyte.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CH1302673A CH582637A5 (en) | 1973-09-11 | 1973-09-11 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1041035A true CA1041035A (en) | 1978-10-24 |
Family
ID=4388639
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA208,756A Expired CA1041035A (en) | 1973-09-11 | 1974-09-09 | Process for the electrochemical fluorination of organic acid halides |
Country Status (9)
| Country | Link |
|---|---|
| JP (1) | JPS5530075B2 (en) |
| BE (1) | BE819731A (en) |
| CA (1) | CA1041035A (en) |
| CH (1) | CH582637A5 (en) |
| DE (1) | DE2442106A1 (en) |
| FR (1) | FR2243274B1 (en) |
| GB (1) | GB1439556A (en) |
| NL (1) | NL7411288A (en) |
| SU (1) | SU598558A3 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8026391B2 (en) | 2005-09-30 | 2011-09-27 | Mitsubishi Materials Corporation | Potassium perfluoroalkanesulfonate and method for producing the same |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2725213B2 (en) * | 1977-06-03 | 1981-06-11 | Bayer Ag, 5090 Leverkusen | Process for the preparation of perfluorinated organic acid fluorides |
| DE4226758C2 (en) * | 1992-08-13 | 1995-11-23 | Bayer Ag | Process for the preparation of perfluoroalkylsulfonyl fluorides |
| US7066321B2 (en) | 1999-07-29 | 2006-06-27 | Kao Corporation | Paper container |
| RU2489416C1 (en) * | 2012-04-27 | 2013-08-10 | Открытое акционерное общество "ГалоПолимер Пермь" | Method of producing perfluorocarboxylic acid |
| CN114277390B (en) * | 2021-12-27 | 2024-03-15 | 上海氟泽新材料有限责任公司 | Fluorination method of 1, 3-dioxocycloalkane acyl fluoride compound and electrolytic fluorination production system |
-
1973
- 1973-09-11 CH CH1302673A patent/CH582637A5/xx not_active IP Right Cessation
-
1974
- 1974-08-23 NL NL7411288A patent/NL7411288A/en not_active Application Discontinuation
- 1974-08-29 GB GB3790574A patent/GB1439556A/en not_active Expired
- 1974-09-03 DE DE2442106A patent/DE2442106A1/en not_active Withdrawn
- 1974-09-09 CA CA208,756A patent/CA1041035A/en not_active Expired
- 1974-09-09 SU SU742057744A patent/SU598558A3/en active
- 1974-09-10 BE BE148371A patent/BE819731A/en unknown
- 1974-09-10 FR FR7430656A patent/FR2243274B1/fr not_active Expired
- 1974-09-11 JP JP10479074A patent/JPS5530075B2/ja not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8026391B2 (en) | 2005-09-30 | 2011-09-27 | Mitsubishi Materials Corporation | Potassium perfluoroalkanesulfonate and method for producing the same |
Also Published As
| Publication number | Publication date |
|---|---|
| DE2442106A1 (en) | 1975-03-13 |
| CH582637A5 (en) | 1976-12-15 |
| JPS5053322A (en) | 1975-05-12 |
| BE819731A (en) | 1975-03-10 |
| FR2243274A1 (en) | 1975-04-04 |
| GB1439556A (en) | 1976-06-16 |
| JPS5530075B2 (en) | 1980-08-08 |
| NL7411288A (en) | 1975-03-13 |
| FR2243274B1 (en) | 1976-10-22 |
| SU598558A3 (en) | 1978-03-15 |
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