US3298940A - Fluorination process - Google Patents

Description

P. E. ASHLEY ET AL FLUORINATION PROCESS Jan 17,. 1967 Q SheetS-Sheet 1 Filed Nov. 8. 1960 R m m Mum L R wwl IAH.A T EE L N mm P K F Y \I B I 0 WW F v. 2 G F ATTORNEY Jan; 17, 1967 Filed Nov. s. 1960 P. 5. ASHLEY ET AL 3,298,940

FLUORINATIONPROCESS 2 Sheets-Sheet z INVENTORS PAUL E. ASHLEY KENNETH J. RADINIER 5W4 sw- ATTORNEY United States Patent 3,298,940 FLUORINATION PROCESS Paul E. Ashley, Minneapolis, Minn., and Kenneth J.

Radimer, Little Falls, N.J., assignors to Minnesota Mining and Manufacturing Company, St. Paul, Minn., a

corporation of Minnesota Filed Nov. 8, 1960, Ser. No. 68,099 7 Claims. (Cl. 204-62) This invention relates to a process for the production of fluorine-containing organic compounds, and more particularly to the electrolytic production of fluorine-containing organic compounds in a molten salt electrolyte utilizing a porous anode.

A number of processes have been described heretofore for the production of fluorine-containing organic compounds. Such processes have been successfully operated to produce the desired end products under the conditions respectively employed. However, in some instances, the prior known processes have employed conditions of reaction which were capable of bringing about extensive disruption of the organic materials used as starting or feed materials. It is therefore of interest and advantage to reduce the temperatures and voltages employed in the electrolytic processes so as to mitigate as far as possible cleavage of the starting materials, while at the same time producing a high degree of fluorination.

It is an object of the present invention to provide a novel and improved process for the production of fluorinecontaining organic compounds.

Another object of the invention is to provide a novel continuous process for the electrolytic production of organic compounds containing fluorine which utilizes mild conditions of reaction while bringing about the introduction of a number of fluorine atoms into the molecule of the feed material.

Another object of the invention is to provide a process for the production of fluoroch-lor-oalkanes.

Other objects of the invention will become apparent to those skilled in the art from the following description.

In accordance with the above and other objects of the invention, it has been found that when a molten salt bath containing hydrogen fluoride is electrolyzed at a relatively low voltage, fluorination of an organic feed material in contact with the anode is brought about with a lessened amount of disruption of carbon-to-carbon bonds. The electrolysis can take place under relatively low temperature conditions, if desired; and it has been found that by appropriate selection of the constituents of the electrolyte the fluorination takes place at temperatures ranging from 78 C. up to 300 C. or higher.

In carrying out the process of the invention, the feed stock is introduced into the electrolytic bath through a porous carbon anode rotating at speeds up to about 1000 rpm. A stationary anode can also be employed, but a rotating anode is preferred. The products of fluorination are continuously withdrawn from the anode as they are formed. During the electrolysis, hydrogen is formed at the cathode and is easily collected in the usual manneror vented as desired. The electrolysis is carried out at a relatively low voltage of the order of about to about volts, and preferably in the range of about 5 to 15 volts. If desired, high current densities can be employed, up to about 0.3 to 0.4 ampere per square centimeter so that large quantities of material can be fluorinated in a relatively short period of time. The process is readily adaptedv to continuous operation.

The products produced by the process of the invention are valuable fluorine-containing organic compounds, which may be referred to herein as fluorocarbons, and that term as used is to be understood as including compounds containing only carbon and fluorine, such as perfluorocar- 3,298,940 Patented Jan. 17, 1967 bons; compounds containing carbon fluorine and another halogen, such as the perfluorochlorocarbons and perfluorobrom-o carbons; and also partially halogenated fluorocarbons such as those containing'hydrogen in addition to halogen, for example, hydrofluorocarbons.

The starting or feed materials which can be used in the electrolytic process of the invention include organic compounds which have an appreciable vapor pressure at the temperature of fusion of the particular electrolyte employed or at least at 300 C., or which are soluble in the electrolyteemployed. Such compounds include the partially halogenated and perhalogenated compounds of both the aliphatic and aromatic series. Such reactants comprise saturated and unsaturated aliphatic compounds hav ing from about one to about 10 carbon atoms per molecule and having halogen other than fluorine as the only halogen substitution; for example, perchloroalkanes, perbromoalkanes, perchlorobromoalkanes, perchloroalkenes, perbromoalkenes, perchlorocycloalkanes, perchlorocycloalkenes, hydrochloroalkanes, hydrobromoalkanes and the like. Typical specific examples of this preferred group of reactants include trichloromethane, dichloromethane, carbon tetrachloride, carbon tetrabromide, chlorobromomethane, chloroform, 1,2-dibromotetrachloroethane, hexachloroethane, 1,1,2,3,3-pentachloropropane, l,2-dichloro propane, trichloroethylene, 1,2-dichloroethylene, bromoethylene, hexachloropropene, perchlorocyclohexene, and the like.

Similarly, there may be employed in the process of the invention compounds containing fluorine as the sole halo gen substituent, as Well as compounds containing fluorine and another halogen. Specific examples of fluorine-containing reactants which can be employed as feed materials for the process of the invention include monochlorodiflnoromethane, 1,1,1-trifluoroethane, 1,2-dibromo-2-chlorotrifluoroethane, bromotrifluoroethylene, and the like.

Halogen-containing aromatic compounds which can be used as reactants in the process of the invention include such typical compounds as hexachlorobenzene, dichloromethylbenzene, benzyl chloride, benzotrichloride, perchlorobiphenyl, and the like.

Further examples of organic compounds which can be used as reactants in the process of the invention, and which produce fluorine-containing organic compounds when subjected to the said process are acyclic, alicyclic and aromatic hydrocarbons, preferably having from 1 to about 10 carbon atoms per molecule and including both unsaturated and saturated compounds, such as, for example, ethylene, acetylene, propylene, cyclohexene, butadiene, benzene, xylene, and the like.

The starting materials for the process may contain other substituents than those enumerated hereinabove, bonded to carbon, such as nitro, hydroxyl, cyano and sulfhydryl radicals, aloneor in addition to the halogen and hydrogen which are also contained in the starting materials. further to be noted that the starting materials can be used in admixture, as well as alone.

Among the useful products which can be produced by the process of the invention are normally gaseous and liquid fluorohalocarbons such as fiuorochloroalkanes and fluorobromoalkanes which can be used as refrigerants, fire extinguishing materials, and propellants. Such compounds are readily prepared using the process of the present invention by employing starting materials which lead to the formation of chlorine and bromine substituted flu'orocar-bons such as CF Cl, CF Cl CF CI, etc. Such materials are readily produced by using a perchloririated compound such as carbon tetrachloride, tetrachloroethylene, octachloropropane and the like as feed stocks. Certain of the products are further valuable for conversion to perflu-oroolefins, e.g. tetrafluoromethylene.

The electrolyte which is employed in the electrolysis cell consists of an anhydrous fluoride salt containing dissolved therein or molecularly absorbed thereon about one to about 3 molecules of hydrogen fluoride for each molecule of salt. Thus, for example, sodium fluoride, potassium fluoride, cesium fluoride, beryllium fluoride, etc. can be employed. By passing HF into such salts, a complex of hydrogen fluoride is formed with simultaneous liquefaction of the particular salt. The number of moles of HF absorbed per mole of salt depends to an extent upon the particular salt which is employed; however, using potassium fluoride, for example, from 1 to 2.5 moles of HF can be employed for each mole of potassium fluoride and even up to to 12 moles of HF per mole of KF when electrolysis is carried out at about room temperature or lower with suitable reflux arrangements. The melting point of the fused salt is thereby reduced, so that KF-HF melts at about 220 C., KF- 1.8 HF melts at about 65 C. and KF-2.=5 HF melts at about 60 C. In each case the vapor pressure of HF over the electrolyte should be less than about 50 mm. of Hg to avoid excessive volatilization. Mixtures of metal fluoride salts containing complexed or adsorbed HF can also be employed, in order to provide particular temperatures of fusion of the electrolyte and for other purposes, for example, for increasing conductivity. About 1% of lithium fluoride is preferably added to assist in minimizing polarization. However, the temperature used in the process can be higher than the fusion temperature of the salt combination; for example, a temperature of 300 C. can be used with a KF -HF electrolyte.

In carrying out the process of the invention, the feed stock or starting material is brought into contact With the fused electrolyte and anode by passing it into the fused electrolyte through the anode. As noted hereinabove, the anode is preferably made of porous carbon, but other materials can be employed, such as porous metals which do not react with the electrolyte. The porosity of the anode may be as interconnected pores as in a sponge or as perforations. While the porous part of the anode may be either at the bottom as in FIGURE 1 or on the sides as in FIGURE 3, the design of FIGURE 1 is preferred since it permits more extensive contact of the vapors with the anode and avoids pulsation in the electrolyte due to build up and release of gas.

When the anode is composed of carbon, it may operate as a source of carbon for the fluorine-containing organic products produced in accordance with the process of the invention. Preferably, the anode is in the form of a hollow rod, or a hollow cylinder which can be rotated. The end of the hollow anode which is immersed in the electrolyte is perforated or porous or so packed with carbon rods or pellets as to permit the passage of the starting materials therethrough. The rate of flow of the added organic reactant is so adjusted as to prevent the flow of molten electrolyte up into the anode and to utilize substantially the entire potential fluorine-output of the cell.

The electrolytic cell which is used for carrying out the process of the invention is, generally speaking, provided with a cathode and an anode, and means for introducing the organic reactant into the cell through the anode, and a means for removing the fluorine-containing organic product as it is formed. Means are also provided for supplying heat to the electrolyte to maintain it in fused condition if the flow of current through the cell is not sufficient to maintain the electrolyte in liquid state, or, alternatively, where high current densities and excessive heat of reaction are encountered, cooling means are provided so as to prevent overheating. Means are also provided for adding hydrogen fluoride in anhydrous condition to the cell either intermittently or continuously at a rate approximately equal to the rate of reaction. The electrolyte, and the hydrogen fluoride added during the course of the reaction, as well as the reactants which are employed as starting materials, are provided in anhydrous condition. However, water if present will be electrolyzed and thus removed, so that the presence of small or trace amounts of moisture at the beginning of the process does not occasion any difficulty in connection with operation of the cell.

The starting material is carried into contact with the electrolyte and anode in the form of a vapor. If the starting material used is normally a gas at the temperature which is employed in the cell, the reactant can be introduced in substantially pure condition. However, inert diluents, such as helium, argon or nitrogen gas, tetrafluoromethane or other inert materials can be employed if desired. Likewise, if the selected starting material is not a gas at the temperature employed, nitrogen or other inert diluent can be saturated with vapors of the reactant at the temperature used, and the saturated gas is then led into the cell through the anode in the usual manner.

While not wishing to be bound by the theory, the results achieved in the process of the invention can be explained on the basis of over-voltage and polarization of the anode. It appears that employing the present process permits ready access of the organic reactant to the surface of the anode where reaction occurs with discharged fluoride ions, represented as F without the formation of F i.e. free fluorine gas. Apparently the formation of F and its release from the anode tends to create a high over-voltage on the anode. By preventing formation of fluorine gas, which is in eflect polarization of the electrode, lower voltages and higher currents are readily obtained and thus greater fluorination occurs with lower power consumption. Employing the process of the invention then effectively depolarizes the anode of the cell. Further support of this hypothesis is provided by the fact that when adequate contact is achieved between organic material and anode, electrolysis proceeds smoothly and quietly. When contact is poorer the process is accompanied by greater amounts of crackling noises which it is believed are due to reaction of fluorine gas with the organic material. Under poor conditions of contact the products from C and higher compounds further tend to show higher concentrations of cleavage products such as CF The voltages are employed in carrying out the electrolysis process of the invention range from about 5 to about 15 volts and the use of voltages in this range has been found to confer certain advantages on the process, such as increased recovery of products having un-cleaved carbon chains. The current density which is employed can vary from about 0.05 ampere per square centimeter of the anode surface in contact with the electrolyte, up to about 0.3 ampere per square centimeter or even slightly higher. Preferably, about 0.2 ampere per square centimeter is employed. It will be understood that actual current densities may be different since it is not possible to determine accurately the effective surface of the porous anodes. It will be apparent that the current which is used determines the rate of fluorination in accordance with electrochemical laws. Consequently, the voltage and amperage which are used and the rate of introduction of organic reactant are so adjusted as to bring about substantially no evolution of fluorine, while at the same time insuring a satisfactory yield of fluorinated end products. In general, a slight excess of the organic reactant is preferred together with the maximum possible current without liberation of substantial amounts of free gaseous fluorine. The presence of free gaseous fluorine is disadvantageous both with respect to its cleavage of the organic molecule and also difficulties encountered when it is present in the products.

The starting material is ordinarily carried into the cell in a stream of inert diluent gas such as helium flowing at a rate of about 50 to 500 ml. per minute for a cell having 7 square inches of anode surface although higher or lower rates of flow may be employed without departing from the scope of the invention. If desired, part of the diluent gas can be added as such without starting material.

The cathode employed in the apparatus may be composed of any. suitably electrically conductive material,

.such ascarbon, silicon, tellurium, Monel metal, nickel,

or other substance which is not attacked by fluorides or hydrogen fluoride. During the electrolysis, hydrogen is formed, at the cathode and is vented or it may be collected if desired. There is substantially no effect on the cathode as a result of the evolution of hydrogen and replacement or cleaning is necessary only after very prolonged operation.

While the presence of hydrogen in the product stream does not ordinarily impose any operating difliculty with respect to separation of the products of the process, it will be apparent that if a suitable shield is interposed between the anode and the cathode, the hydrogen may be obtained in substantially pure form. At the same time, shielding of the anode permits recycling of the products if desired, to produce higher degrees of fluorination.

The electrolytic cell employed in the process of the invention is operated with direct current, including rectified alternating current.

The pressure which is used to carry out the process .of the invention canrange from a few millimeters of mercury to superatmospheric pressure. By enclosing the entire electrolysis cell within a pressure vessel, it will be apparent that the external pressure can be varied as desired. It is necessary only that the pressure of the incoming gases carrying the reactant be sufliciently higher to prevent the molten electrolyte from entering the hollow anode. However, it is preferred to carry out the process at atmospheric pressure.

The accompanying drawings will aid in understanding the invention. Referring to the drawings, FIGURE 1 represents a diagrammatic elevation in cross-section, on a diameter thereof, of an electrolysis cell which is one embodiment of the invention.

FIGURE 2 represents a plan view of the bottom of a rotating hollow anode suitable for use in the apparatus of the invention.

FIGURE 3 represents a diagramamtic cross-sectional elevation of another embodiment of the invention.

In FIGURE 1 a cylindrical container of Monel metal serves to contain the electrolyte and also as the cathode. A jacket 11 surrounds the vessel, enclosing between the walls of the jacket and the vessel heating wires 14, embedded in a ceramic insulating material 15. The electrolyte 16 is contained within the vessel; an inlet tube 18, also of Monel metal, serves for the introduction of hydrogen fluoride into the molten electrolyte. Suspended in the electrolyte is the anode 20, which has a porous carbon face 21. The cylindrical body of the anode is attached to hollow shaft 23, which is provided with means for rotation, but (not shown), such as a flexible connection to an electric stirring motor. Surrounding the shaft is a housing 25, having insulating seals 26 and an inlet tube 27. The hollow shaft 23 is provided with holes or apertures 28, through which gases may enter the anode 20; and the shaft is conductively connected with the anode so as to supply electric current thereto. A combined'insulating bearing and seal 29 is provided, through which the shaft carrying the anode enters the chamber defined by the anode shield 31. The anode shield surrounds the anode for the purpose of containing the reaction products. An inlet tube 32 and an outlet tube 34 are attached to the anode shield, to provide for the exit of the reaction products as well as for introduction of gases to sweep out the residual air, etc. which may be present in the anode chamber. A microporous deflector 35 is provided below the anode shield, to prevent the entry of hydrogen gas from the cathode into the space beneath the anode shield, so as to avoid diluting the reaction products with hydrogen. The deflector 35 is suitably supported in position, as by supporting legs 36. The cylindrical anode 20 is provided with stirring vanes-22, also shown in FIGURE 2,

which aid in circulation of the electrolyte and prevent polarization effects at the face of the anode. A brush 26a is used to contact the rotating shaft 23, for the purpose of providing an electrical connection.

Shaft 23 is conveniently made of copper or Monel metal or of any other substance which conducts electricity and resists the action of the fused salt bath. The seals 26 and 29 are likewise made of a material which resists the action of hydrofluoric acid and fluorine, for example, a fluorinated polymer such as polytetrafluoromethylene or the like. Similarly, the anode shield 31 is conveniently made of polytetrafluoroethylene. If desired, a cover can be placed over the entire top of the vessel which contains the electrolyte, with appropriate openings for the inlet and outlet tubes 34 and 32 and for I-IF supplied to 18, and shaft 23, together with a separate outlet tube for the hydrogen which is formed during the process.

In FIG. 3, there is. shown another embodiment of the invention, in which a suitable vessel 51 serves for containing electrolyte 52, and is surrounded by a heating jacket 54. The space between the heating jacket 54 and the outside wall of the vessel 51 can be heated, for example, with steam or hot water, or cooled as with cold water or brine, through inlet and outlet ports 55 and 56, respectively. Suitably suspended in the vessel 51 is an anode shield 57 of an inlert polymer such .as polytetrafluoroethylene or polytrifluorochloroethylene provided with a product outlet tube 58. It is particularly advantageous to construct the anode shield 57 from an inert polymer as it is then electrically non-conductive and thereby avoids two difficulties which may otherwise be encountered. The one is that when fabricated from a conductive material it may act as an intermediate electrode, the outer-surface being an anode with respect to the external cathode and the inner surface a cathode with respect to the central anode. Under such circumstances hydrogen and fluorine may both be generated in the same compartment and recombine violently. A similar effect is obtained due to accidental shorting of the anode to a conductive shield as may occur if the anode breaks off in operation and floats on the electrolyte. The anode shield supports a tube 60, to which is attached anode 61 and insulating packing 63 and gland 64 serve to isolate the anode from the anode shield. A cover 65 sealed by insulating gasket rings 67 and 68, and having exit tube 69 prevents the escape of-hydrogen gas from the apparatus and provides for its collection. Tube 60, conveniently made of copper or Monel metal, supports the porous anode 61 and serves to conduct electricity thereto. The metal container 51 serves directly as a cathode and is connected to the negative side of the electrical source.

Referring to the apparatus of FIG. 1, in operation, the electrolyte 16 is warmed by means of the heating coils 14 until it is molten. A source of direct current is then applied to the terminals of the anode and the cathode, and the anode is set in rotation. The starting materials are then introduced through housing 27, as for example, as a gas, which is under sufficient pressure to keep the molten electrolyte out of the anode, and to maintain a continuous flow of gas through the porous face of the anode without excessive bubbling. Anhydrous hydrogen fluoride gas is introduced into the electrolyte bath at about the same rate as the depletion of the electrolyte takes place through electrolysis. The current is regulated so that no fluorine is formed. The presence of fluorine can be detected by means of potassium iodide-starch paper or even filter paper impregnated with dilute potassium iodide solution. The reaction products are removed through tube 34, and are fractionated in the usual apparatus (not shown) adapted for distillation or the like. If desired, additional inert gas can be introduced at inlet 32, to sweep the reaction products out of the reaction cell.

The embodiment of the invention shown in FIG. 3 operates in substantially the same manner, save that it is better adapted for use in batch operations. As noted hereinabove, the electrolyte is fused as by application of concomitant electrolysis of said hydrofluoric acid whereby a perfluorinated hydrocarbon is obtained.

2. A process for the electrolytic production of perfluoroalkanes which comprises electrolyzing an anhydrous heat in the jacket 54, a source of direct current is atelectrolyte consisting essentially of hydrogen fluoride and tached to :the appropriate anode and cathode connectors at least one alkali metal fluoride, feeding to the elecand th mat rial t be fluorinated is introduced through trolytic cell a partially fluorinated saturated hydrocarbon the P of tube into the Porous anoda' When a consisting of at least two carbon atoms substituted solely Porous pp to fofaminous) anode is employed by at least two fluorine atoms, and recovering a perit is preferable to avoid wetting the inside of the anode 1O fiuoroalkane as a product by the electrolyte which may Prevent PaFSage of gas 3. A process for the electrolytic production of fluorine through the Pores The products of Ramon ,leave the containing organic compound according to claim 2 Whereg g gi gg the in the anhydrous electrolyte is fluid and in electrical actlon can e co ecte t mug tu r contact with an inert cathode and a hollow rotating porous Example anode open internally to the said electrolyte and at a potential difference between said cathode and anode can of the type F 1 with. horizontal sufficient to effect electrolysis of said electrolyte and up .rotatmg. anode vanpusly dllutad Wlth nitrogen to about 20 volts and wherein a :gas comprising an organic 1S fluonna'ied employmg f i f E}; anodel 20 compound contacts the electrolyte-contacting surface 9f i i :OnS.tant t gg T t 1 tom said anode below the surface of said electrolyte and pro- Ijoug Pu 9 an a mmu m mgen vides the dissolved saturated hydrocarbon substituted being added 1n sufiicient amount to bring the volume to O1 1 b t 16 St TWO fluorine atoms this figure. Rate of rotation of the anode is as given 8 Z a a t I h th h in the following table. Vapor phase chromatography process accor 0 calm W erem e an and conventional integration of the curves enables the 25 dfous electrolyte COIltflHlS f ltO 12 mol s of hydrogen calculation of mole fractions of the major products (based fluoride P mole of metalllc l and Potentlal differon products only excluding unreacted starting material). ence w n anode and Cathode 1 fr m o t 5 to ut The products are all gaseous. The results are sum- V lts. marized in the following table. 5. A process according to claim 4 wherein the metallic TABLE C911 Anode Mole percent of products Volume Conversion, Temp, Power Input, Speed, Feed, Percent Acetylene cc./amp./ 0. volts amps. r.p.1n. cc./min. conversion reacted min.

CF4 CzFa C2F5H C2F4H2 per min.

6.9 4.0 575 70 13 16 71 3.1 2.1 0.52 8. 1 6. 0 620 70 31 2s 5 36 3. 6 2. 5 0. 42 9. 1 10. 0 700 70 20 32 5 42 11 7. 7 0. 77 5. 9 2. 0 630 20 34 9 32 5. 6 1. 1 0. 55 7. 0 4. 0 670 20 19 5 46 19 3. 7 0. 92 7. 8 6. 0 750 20 20 31 4 29 5. s 0. 97 3. 4 s. 0 s20 20 16 39 4 42 46 9. 2 1.15 8.3 10.0 960 20 20 24 7 49 52 10.4 1. 04 6. 4 4. 0 s 10 34 5 34 2s 56 5. 6 1. 49 7. 2 6.0 300 10 26 9 20 44 34 a. 4 1. 40

Of acetylene, sufficient nitrogen to make 150 cc.

b Number of unknown products, not taken into account in yield figures, is usually two or one.

From the data in the table best efiiciencies are obtained with low concentrations of acetylene in the feed gas and anode speeds above about 800 rpm. for this particular system. This does not, however, take into account the particular proportions of products formed. The lowest concentration employed in which the acetylene would have a partial pressure of about 50 mm. of Hg does not of course represent the minimum concentration suitable for the process of the invention. The concentration and rate of introduction should be at least suflicient to pro vide potentially suflicient organic material for complete utilization of the output of the electrolysis so as to avoid any substantial evolution of fluorine gas. At suflicient rates of introduction, a concentration as low as about 1% at which is exhibited a partial pressure of about 5 mm. of Hg is suitable and concentrations up to complete saturation with a liquid at temperatures up to about the temperature of the electrolyte and to 100% by volume for gaseous reactants may be employed. The process can be carried on continuously by gradually replenishing the hydrogen fluoride which is consumed.

What is claimed is:

1. A process for the preparation of fluorinated organic compounds comprising the step of subjecting an acetylenic hydrocarbon to the action of liquid anhydrous hydrofluoric acid, containing therein a soluble conductivity promoting alkali metal salt of hydrofluoric acid, during fluoride is potassium fluoride and the potential difference is not higher than about 15 volts.

6. A process according to claim 4 wherein the anhydrous electrolyte comprises 1 to 2.5 moles of hydrogen fluoride per mole of potassium fluoride and about 1 percent by weight of lithium fluoride and the potential differonce is from about 5 to 15 volts.

7. A process for the preparation of fluorinated organic compounds comprising the step of subjecting an unsaturated hydrocarbon to the action of liquid anhydrous hydrofluoric acid, containing therein a soluble conductivity promoting alkali metal salt of hydrofluoric acid, during concomitant electrolysis at a voltage of from about 5 to about 15 volts of said hydrofluoric acid whereby a perfluorinated hydrocarbon is obtained.

References Cited by the Examiner UNITED STATES PATENTS 8/1950 Simons '20462 7/1958 Radimer 204-62 JOHN H. MACK, Primary Examiner.

JOHN R. SPECK, WINSTON DOUGLAS Assistant Examiners.

Claims (2)

1. A PROCESS FOR THE PREPARATION OF FLUORINATED ORGANIC COMPOUNDS COMPRISING THE STEP OF SUBJECTING AN ACETYLENIC HYDROCARBON TO THE ACTION OF LIQUID ANHYDROUS HYDROFLUORIC ACID, CONTAINING THEREIN A SOLUBLE CONDUCTIVITY PROMOTING ALKALI METAL SALT OF HYDROFLUORIC ACID, DURING CONCOMITANT ELECTROLYSIS OF SAID HYDROFLUORIC ACID WHEREBY A PERFLUORINATED HYDROCARBON IS OBTAINED.

2. A PROCESS FOR THE ELECTROLYTIC PRODUCTION OF PERFLUOROALKANES WHICH COMPRISES ELECTROLLYZING AN ANHYDROUS ELECTROLYTE CONSISTING ESSENTIALLY OF HYDROGEN FLUORIDE AND AT LEAST ONE ALKALI METAL FLUORIDE, FEEDING TO THE ELECTROLYTIC CELL A PARTIALLY FLUORINATED SATURATED HYDROCARBON CONSISTING OF AT LEAST TWO CARBON ATOMS SUBSTITUTED SOLELY BY AT LEAST TWO FLUORINE ATOMS, AND RECOVERING A PERFLUOROALKANE AS A PRODUCT.

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