(12) United States Patent (10) Patent No.: US 6,391,182 B2 Smeltzer Et Al
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USOO6391.182B2 (12) United States Patent (10) Patent No.: US 6,391,182 B2 Smeltzer et al. (45) Date of Patent: May 21, 2002 (54) ELECTROCHEMICAL FLUORINATION 5,286.352 A 2/1994 Hansen et al. ............ 204/59 F USING INTERRUPTED CURRENT 5,322,597 A 6/1994 Childs et al. ............. 204/59 F 5,387.323 A 2/1995 Minday et al. ........... 204/59 F (75) Inventors: John C. Smeltzer, Woodbury, MN 5,427,656 A 6/1995 Behr et al. ................ 204/59 F (US); Charles F. Kolpin, River Falls, 5,474,657 A 12/1995 Hansen et al. - - - - - - - - - - - - 204/59 F WI (US) FOREIGN PATENT DOCUMENTS (73) Assignee: 3M Innovative Properties Company, DE 741,399 11/1955 St. Paul, MN (US) DE 785492 10/1957 FR 2 604 189 3/1988 (*) Notice: Subject to any disclaimer, the term of this WO WO 94/13857 6/1994 patent is extended or adjusted under 35 U.S.C. 154(b) by 0 days. OTHER PUBLICATIONS AlsmeySmeyer et al.,1. “El ectrochemicahemical FluorinatiuOrnation andd iItS (21) Appl. No.: 09/833,360 Applications,” Organofluorine Chemistry. Principles and (22) Filed: Apr. 12, 2001 Commerical Applications, Chapter 5 (1994) pp. 121-143. O O No Month Available. Related U.S. Application Data W.V. Childs, et al., “Anodic Fluorination' Organic Electro (60) Divisionivision of application No. 09/464,781,föl, filedilled onOn Dec.Jec. 17If, chemistry, H. Lund and M. Bazer eds, Marcel Dekker Inc., application1999, now Pat.No. No. 09/074,830, 6,267,865, filed and aon continuation-in-part May 8, 1998, now of Ney. Y.R. ge, (9) ectrochemica pp. s N uorination,Month Avait. Industria ial abandoned, and a continuation-in-part of application No. Electrochemical Processes, Chapter 2, (1971) pp.71-88. No 09/070,382, filed on Apr. 30, 1998, now abandoned. Month Available. (60) Provisional application No. 60/045,514, filed on May 2, 1997. (List continued on next page.) (51) Int. Cl." .............................. C25B 3/08; C25B 3.06 (74)Primary Attorney, Examiner-Edna Agent, or Firm-Lisa Wong M. Fagan (52) U.S. Cl. ........................................ 205/460; 205/461 (57) ABSTRACT (58) Field of Search .................................. 205/460, 461 Described is a process for the electrochemical fluorination of (56) References Cited a Substrate, the process comprising the Steps of: providing a Substrate comprising at least one carbon-bonded hydrogen; U.S. PATENT DOCUMENTS preparing a reaction Solution comprising the SubStrate and 2,519,983 A 8/1950 Simons ....................... 2042 hydrogen fluoride; passing electric current through the reac 2,616,927. A 11/1952 Kauck et al. .. ... 260/S63 tion Solution Sufficient to cause replacement of one or more 2,713,593 A 7/1955 Brice et al. ....... ... 260/535 hydrogens of the Substrate with fluorine, the electric current 3,028,321 A 4/1962 Danielson et al. ............ 204/59 being interrupted through a current cycle defined by current 3,692,643 A 9/1972 Holland ....................... 204/59 levels comprising an elevated current and a reduced current; 3.919,057. A 11/1975 Plattner et al. 204/59 F wherein the current varies in Such a manner that the resis 3.950,235 A 4/1976 Benninger ............... 204/59 tance of the cell operated with interrupted current is lower 3.962,348 A 6/1976 Benninger et al. 260/615 F than the resistance of the cell operated with non-interrupted 3,980,534 A 9/1976 Drakesmith .................. 204/59 Current 4,739,103 A 4/1988 Hansen et al. .... ... 560/125 4,788,339 A 11/1988 Moore et al. .. ... 564/457 5,108,556 A 4/1992 Richman .................. 204/59 F 4 Claims, 4 Drawing Sheets ORGANICFEED CONNSERS ED DECANTER 10 ELECTROLYE EFC CELL CHAS 2. 16 CIRCUAION - CLCRUDE PUMP US 6,391,182 B2 Page 2 OTHER PUBLICATIONS Simons et al., “Fluorine Chemistry,” Academic Press, Inc., J.A. Donohue et al., “Pulsed Electrolysis of Wet Hydrogen vol. 1, (1950) pp. 414–420. No Month Available. Fluoride,” J. Electrochem. Soc., vol. 115, No. 10, (1968) pp. Watanabe et al., “Electrochemical Fluorination of Acetoni 1039–1042. No Month Available. trile, Asahi Garasu Kogyo Gijutsu Shoreikai Kenkyu J.A. Donohue et al., “The Nickel/Nickel Fluoride Anode in Wet Hydrogen Fluoride,” J. Electrochem. Soc., vol. 115, No. Hokoku, vol. Date 1975, vol. 27, pp. 1-10. No Month 10, (1968) pp. 1042–1045. No Month Available. Available. J.H. Simons, Fluorine Chemistry, Academic Press, Inc., Dmowski et al., “Electrochemical Fluorination of Methyl New York, vol. 1 (1950), pp. 414–420. No Month Available. Cinnamates in EtN* 3HF-MeCN.” Electrochimica Acta., S. Nagase, “Electrochemical Fluorination,” Fluorine Chem istry Reviews, 1(1(1967)), pp. 77-106. No Month Available. Vo. 42, No. 44 (1997) pp. 513–523. Month unavailable. Noel et al., “A Review of Recent Developments in the Lines et al., “The Electrochemical Fluorinationof Octanoyl Selective Electrochemical Fluorination of Organic Com Fluoride with Electrolyte Circulation,” Journal of Fluorine pounds,” J. of Fluorine Chem., vol. 83 (1997) pp. 31-40. No Month Available. Chemistry, vol. 17 (1981) pp. 423-439. Month unavailable. Burdon et al., “The Electrochemical Process for the Syn Abe et al., “The electrochemical Fluroination of C-Alkyl thesis of Fluoro-Organic Compounds,” Advances in Fluo Substituted Carboxylic Acids,” Journal of Fluorine Chem rine Chemistry, vol. 1, (1960) pp. 129-165. istry, vol. 12 (1978) pp. 1-25. Month unvailable. Saffarian, H. et al., “Electrochemical Properties of Perfluo roalkane Disulfonic HSO(CF2), SOHAcids Relevant to Moore et al., “Electrochemical Fluorination of Aminoalkyl Fuel Cell Technology,” J. Electrochem. Soc., vol. 139, No. Ethers,” Journal of Fluorine Chemistry, vol. 32 (1986) pp. 9 (Sep.1992) pp. 2391-2397. 41-76. Month unavailable. U.S. Patent May 21, 2002 Sheet 1 of 4 US 6,391,182 B2 TIME (S) Fig. 1 prop TIME (S) Fig. 2 U.S. Patent May 21, 2002 Sheet 2 of 4 US 6,391,182 B2 TIME (S) Fig. 3 TIME (S) Fig. 4 U.S. Patent May 21, 2002 Sheet 3 of 4 US 6,391,182 B2 P P P TIME (S) Fig. 5 TIME (S) Fig. 6 TERMINAL VOLTAGE Fig. 7 U.S. Patent May 21, 2002 Sheet 4 of 4 US 6,391,182 B2 CEE HELNW/OEC) SHESNEIGINOO ESV/HdO-H T?TEHOO-IE EGITEKOTTEO US 6,391,182 B2 1 2 ELECTROCHEMICAL FLUORINATION and J. C. Tatlow, The Electrochemical Process for the USING INTERRUPTED CURRENT Synthesis of Fluoro-Organic Compounds, Advances in Fluo rine Chemistry, edited by M. Stacey et al., volume 1 p. 129 CROSS-REFERENCE TO RELATED (1960). Conductivity additives can cause undesired results APPLICATION when used in the Simons proceSS. Conductivity additives, for example, can interfere with the fluorination of the This is a divisional of application Ser. No. 09/464,781 Substrate, either by causing increased corrosion of the anode, filed Dec. 17, 1999. now U.S. Pat. No. 6,267,865. or by themselves being consumed or fluorinated in the This application is a continuation-in-part of application fluorination reaction. This can reduce the overall yield of the Ser. No. 09/070,382, filed Apr. 30, 1998, now abandoned desired fluorinated product, and in many ways can increase and claims the benefit of U.S. Provisional Pat. App. Ser. No. the costs of the fluorination operation. Therefore, it would be 60/045,514, filed May 2, 1997; this application is further a desirable to reduce or even Substantially eliminate the need continuation-in-part of application Ser. No. 09/074,830, for conductivity additives. filed May 8, 1998 now abandoned. Finally, the Simons proceSS can be difficult to maintain at 15 Steady State for extended periods of time because high FIELD OF THE INVENTION resistance by-product films and tars can tend to accumulate The present invention relates to a process for the electro on electrodes of the fluorination cell, Specifically, at the chemical fluorination of organic materials. anode. In normal operation, the accumulation of films and tars on the anode causes increased resistance of the electro BACKGROUND chemical cell, and an upward drift in cell Voltage. The Fluorochemicals (e.g., fluorinated and perfluorinated problem can become more Serious and lead to the condition organic compounds) are commercially valuable and useful referred to as "current blocking,” which is manifested as a chemical materials. Fluorochemicals can exhibit various permanent increase of resistance and loss of conductivity useful properties, e.g., they may be inert, nonpolar, within the cell. To correct current blocking often requires hydrophobic, oleophobic, etc. AS Such, fluorochemicals can 25 shut-down of the apparatus for cleaning. It would therefore be useful in a wide variety of applications. They can be be desirable to prevent increases in the resistance of a useful as oil, water, and Stain resistant chemicals; they can fluorination cell that can lead to loss of conductivity within be useful as refrigerants and heat eXchange agents, or as the cell, and the permanent condition of current blocking. Solvents and cleaning agents. Due to the versatility of SUMMARY OF THE INVENTION fluorochemicals, and a consequent Strong demand for these The present invention relates to a process for the electro materials, there is a continuing need in the fluorochemical chemical fluorination of chemical compounds Such as those industry for new and improved methods of preparing fluo containing organic moieties. In the process, a reaction Solu rochemicals. tion is provided that comprises an organic Substrate and One well-known industrial process for preparing fluoro 35 hydrogen fluoride. An electric potential (voltage) is estab chemical compounds is the electrochemical fluorination lished across the reaction Solution causing an electric current process commercialized initially in the 1950s by the 3M to pass through the reaction Solution, and thereby causing Company.