A,G. 22, 1950 J.H. SIMONS 2,519,983 1010.0001
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A,g. 22, 1950 J.H. SIMONS 2,519,983 ELECTROCHEHICAL PR0~ESS 0F ItChING FLUORINE-CONTAINZNG CARBON~C01iPOUNDS F~A.ed Nov. 29, 1946 I for pr~dvcfs Exhibit 1010 State of Minnesota v. 3M Co., Court File No. 27-CV-10-28862 STATE_07524631 1010.0001 Patented Aug. 22, 1950 2,519,983 UNITED STATES PATENT OFFICE 2,519,988 ELECTROCHEMICAL PROCESS OF M~I~N’G FLUORiNE-CONTAINING CARBON (~OM- POUNDS Joseph H. Simons, State College, Pa., assignor to Minnesota Mining & Manufacturing Company, St. Paul, Minn., a corporation of DeLaware Application November 29, 1948, Serial No. 62,496 20 Claims. (CI. 204---62) ! This application is a continuation-in-part of dlt~ves to permit of electrolyzing liquid hydrogen my copending application Ser. No. 677,407 (filed fluoride solutions thereof admixed with rela- June 17, 1946), since abandoned. The latter was tively insoluble organic starting compounds, such filed as a continuation-in-part of the following as alkanes, which do not provide adequate con- prior applications which thereafter were aban- ~ ductivity. Pure anhydrous liquid hydrogen fluo- doned in its favor: Set. Nos. 384,729 (filed March ride, per se, is non-conductive. The electrolyte 22, 1941), 569.265 (filed December 21, 1944), and is free trom water in more than a small pro- 626,434 (filed November 2,1945). portion but need not be anhydrous in a strict This inve~ntlon relates to my discovery of a sense, basically new process of making fluorocarbons 10 Excellent results can be obtained with simple and other fluorine-containing carbon compounds. single compartment electrolytio cell arrange- The process is simple in operation, does not in- ments. No diaphragm is needed between elec- volve the use or formation of free fluorine at any trodes. Fluorination can be completed in one stage, and has great versatility in enabling the step to directly obtain fully fluorinated product direct production of many. types of product com- 1~ compounds which are relatively insoluble and pounds using organic startlng compounds which either evolve with the cell gases or settle to the are readily available and relatively inexpensive. bottom of the cell from which they can be It is an electrochemical process and its utility drained, depending upon their boiling lmints. has been demonstrated by extensive pilot plant The process ~ suitable for continuous as well as operations employing a 2000-ampere cell, as well 20 batch operation. The .cell can be operated at as by many laboratory experiments. atmospheric pressure. The cell and the cathodes This process was publicly disclosed in the oral can be made of iron or steel, and the anodes of presentation on September 15, 1948, at the Port- nickel, and such cells have been satisfactorily land, Oregon, session of the 114th meeting of t~c operated at 5 to 8volts, D. C., in producing a wide American Chemical Society, of five papers ~ variety of product compounds. thored by me and my assistants. Abstracts of The reaction mechanism ls not fully under- these papers had been previously published in stood but the electrolyzing process apparently the advance "Abstracts of Papers" volume issued transforms the organic starting compounds at or by the society (pp. 42-0 to 45-0). News items adjacent to the anode and may be regarded as an relating thereto and briefly describing the process 30 anodic process. Hydrogen is evolved at the cath- have been published in the society’s magazine ode, being derived from the hydrogen fluoride; Chemical and Engineering News, col. 26, p. 2428 and will also evolve in the cell by derivation from (Aug. 16, 1948) and pp. 2878-9 (Sept. 97, 1948). other hydrogen-containing compounds which These papers were subsequently publlahed in the may be present, l~uorinc is not evolved, and the Journal of the Electrochemical SocietY. col. 95, a5 reaction mechanism doe~ not involve the forma- No. 2, pp. 47-67 (Feb. 1949). tion of molecular (free elemental) fluorine as an Briefly stated, this new and useful electro- intermediate agent. chemical process involves electrolyzing a liquid Product compounds are obtainable (both cyclic hydrogen fluoride (HF) solution containing a and non-cyclic) which have the same number of fluorinatable organic starting compound, at an 40 carbon atoms and same carbon skeletal structure electrolyzing potential which is insufficient to as do the starting compounds, but with partial generate free fluorine under the existing condi- or total fluorine atom replacement of hydrogen tions, but which is sufficient to cause the pro- atoms and other atom_s and radicals bonded to duction of fluorine-containing carbon compound the carbon skeleton of the molecule. Fluorine products at a useful rate. A wide variety of 45 addltlon occurs In the case of unsaturated and organic compounds are soluble in anhydrous aromatic types of starting compounds to produce liquid hydrogen fluoride and provide adequate fully saturated product compounds. Non-cyclic electrolytic conductivity. Use can also be made compounds (in addition to cyclic compounds) of eoluble organic and inorganic conductivity ad- having the same number of carbon atoms are oh- STATE_07524632 1010.0002 tainable from cyclic starUng co~Potmds u tile result of bond cleavage and fluorine addition. Ako, the use of polycarbon cyclic and non-cyclic starU~ compounds generally results in ~ppre- cMble yields of product compounds lmvtng fewer ~ atom~ in.the molecule, due to tragmenta- .-tlo~ Of the carb(m akeleton and fluorine addition. (~mpom~ h~vin~ L ~’e~tor number of ~mm than the starth~ compounds are obtain- formed in the aoluflo~ The klnds ~i ~elative an~ riven ease will depend upon the startJ~ proper selectloea it is possible to obtain exce~ent ~ of desired px~ducts, which can be read~ separated by fractional distillation from each other and from low-yield by-product In _c~mmerclalopemtions, use canbemade of the productl~ of multiple products in bu~dtn~ up Mz~m of,many rueful compounds from a much mo~e limited number of ~ compounds. In m~me caees r~dnous mterlal is formed in flum~ne in proportio~ up to 60~ have been ob- tained. In man~ cases .no. solid residual mato- rl~ aee found even ~fter extended use of the cell. In i~eneral, there is little or no corroaton Of of the process in enabling the prOdUction of fluorocarbon derivatives, mention is made (for illustration and notlimitation) of the fotlowin~ t~pes designated bY generic formulae wherein It represents saturated fluo~carbon radicals (cycli~ or non-cyclic) ons~tn_~. solely of carbon and fluorine atoms: It’OIt" (obtainable from ethers) R’R"R"’N (obtainable from tertiary It°R’°N1~ (obtainable from seco~ imlnes), ~ (obtainable from prlmar~ an~lnes), R~"~)~’ (obtainable from monocarboxylic acids), (obtainable from esters), ~ (obt~inable from nitrile~) and ~ (obt~5,~_ble from mercaptan~). Fluorocarbon compounds which contain com- bined chlorine can be obtained from chlorine- contatnin~ etartin~ compo~m~ (e. g., chloro- s~etlc ~d). Heterocyclio compounds contain- ln~ one or more origen or nitrogen atoms in the ~ ~n be obtained by replacement of the hydrogen atoms-by fluorine atoms ~n stm~d~ compounds cf corresponding structure. True fluorocarbons (carbon fluorides cont~u- in~ only carbon and fluorine atoms) can be dtre~ly obtained from hydrocarbon starfl~ compotmds, and ~ by electroly~n_~ solutions of various hydrocarbon derivatives, to obtain s~ntial yields of fluorocarbons havin~ the ¯ ame number of carbon atoms~ the startin~ flum~o~arbons h~vin~ the same number of e~rbon ¯nd m~e carbon, atoms are produced. INuoro- e~rbons havin~ fewer carbon atoms th~n the startl~ compound can also. be produced from hetero compounds wherein earben atoms m STATE_07524633 1010.0003 lar Value ~or making fluorocarbolls, add ~u0r0- for the generation of free fluorine (I~) is carbon derivatives of chief commercial interest. proximately 3 volts. The reason why total cell are the hydrocarbons (which contain only car- voltages higher than this can be used in actual bon and hyclrogen), and the compounds which practice of the process without causing free fluoo are oxygen-containing or uitrogen-cont~tntng in fine formation is because a substantial part of addition to being bydrogen-contalnlng, Exem- the total cell voltage (measured across external plary of the latter are the cyclic and non-cyclic anode and Cathode connections) is utilized under organic acids, alcoholsi ethers, esters, ketches, the existing conditions in overcoming the resist- aldehydes, nitriles, amines, amides, etc. These ances of the electrodes, the resistance of the elec- oxygen-containing and nitrogen-containing or= l0 trolyte between the electrodas, and the blocking ganic starting compounds are soluble in anhyo resistances of electrode polarization films. drous liquid hydrogen fluoride and provide ade- In an experiment using a carbon-anode cell it quate conductivity, no conductivity additive being was found that electrolysis of a hydrogen fluoride needed. The hydrocarbons (which are relatively solution of acetic acid resulted in the formation insoluble) can be employed when use is made of 15 of flucromethane (CI~F) at a cen voltage as low a conductivity additive, as explained in some as abou~ 0.5 volt. In another experiment using a detail later on. These ~ub-lasses embrace the nickel-anode cell, a hydrogen fluoride solution of readily available and relatively Inexpensive alo acetonltrlle (CI-I~CN) was electrolyzed for five kanes, alcohols, ethers, carboxylic acids (includ- days at a cell voltage of 1.~ volts and the prod- ing the anhydride forms), and amines, both 20 ucts included C~’~CN, CF~H, CF~, C~H and C~F~. c~’clic and non-cyclic, which can all be el~elently These cell voltage values were very substantially employed in the preparation of fluorocarbons and lower than the minimum cell voltage (approxi- of other Iluorineocontalning carbon compounds.