FLUORINE CHEMISTRY Edited l)~. ,J. 1.1[. VOLUME I !950 ACADEMIC PRESS INC., PUBLISHERS NEW YORK, N. Y. Exhibit 3008 State of Minnesota v, 3M Co,, Court File No, 27-CV-10-28862 STATE 07525275 3008.0001 STATE 07525276 3008.0002 CIIAPTER ! 2 Fluorocarbons and Their Production ]~Y J. II. SIMONS Fluorine Lal~oralorie~, The l)enn,~ylvania ~ate Colh’ge, State ])age Introduction ............................................................ 401 Fluoroca, rbon Nomenclature .............................................. 404 Ear+y History ........................................................... 406 The (’~+xtalyzed React, ion hetween Fh+<>rit+e a+l+l Car!)<m ....................... 407 ~¢ent History .......................................................... 408 CatMyzed FIuorine and (:ari)(m Reaciim+--.Piiot l’l+mt Study. ................ 409 The Electro¢+hemica~ Process .............................................. Liquid Phase Fhu)rflmtion ................................................. 420 t~ibiiography ........................................................... 422 Introduction The fluorocarbons are (leseined to 1)eeome a new and very large domain of chemistry. They can be expected in the not too distant fl+ture to rival that branch of chemistry catIed organic. As ~heir name implies, they are compounds of fluorine and carbon; but i~ a more restricted sense they are compounds, analogous t:o hydrocarbons, with fluorine atoms occupying the positions of hydrogen a~oms in hydrocarbons. .Chemically, however, the properties of these compounds are so vastly different from their hydr~+gen-containing m+alogs that e~+~ircly new and i different techniques, methods of synthesis, and reactions are necessary. Hydrocarbons and their derivat.ives, i.e., organic chemical compounds, are extreraely useful for mankind, these uses being chiefly in t.wo impel rant areas. They are very reactive substances which are particularly susceptible toward oxidation. For ~his reason they are extensively used for fuel and for food. Oxidation is without question ++he mest important organic chemical reaction. The other area in which organic compounds are useful is as materials cf construction such as wood, paint, lubricants, fabrics, pIastics, and rubber. Here this ease of combustion is high|y disadvantagcous. Slow oxidat~ion cau~cu deterioration +~s in paint, dyes, and rubber; and rapid oxidation causes tremendous destruction of life and property in fires. 40t STATE 07525277 3008.0003 The, fluorocarbons and t.heir (leriw~(;ives ~l)pe:Lr destined to fill role of "~nM,eriMs of const.ruct, ion" eomplcL{~ly free from the rav~ of either slow or rapid oxidation, so i~ this :~rea. t, tmy shouhi be superior to m’ganic chemical subst.~mces. 5’l(~s{, org~.tnic compot~nd~ subject to gradual dcteriorat,hm by slow oxithd.iot~, but the fluorocarbo~ are free from this defect. For ghc s~mc re:.~s~m b~cterial life and cannot use fluorocarbon material for food, and sul)st;~nces m~de fro~ pro~ected by fluo:’ocarbons ~re free fr(m~ dcet~y ~mI insect da~ag~ Fluorocarbons arc completely non~rg~nic, when i I.. comes to being eith( used er produced by organisms, h~ :Mdition t,o t)eing comple[ely ~o~: e<>mbusti!)le, the fluorocarbons arc vesisl,a~+t t() 1.he action of ehe~+ic~ agents, including ~he strong acids ~nd l}~ses a.~M strong oxidizing reduci~g t~g(~nts. TA B13~i I Band Enerffi~’s F ( ;1 lh" ! I! C Bond radii F 63.5 86,4 147.5 1107.0 0.64 CI 8(). 4 57.8 52.7 51,0 102.7 66.5 0, ]~r 52.7 ,16. [ 42.9 87~3 54.0 1,1,4 I 51.0 42,9 36.2 71,4 45.5 :It 147.5 102.7 87.3 71 4 103.4 87~3 0.30 C 107.0 66.5 54.0 45.5 87.3 58~6 0.77 Prior to the lirst identification of liquid [ltmroc’,~rl)ons in 1937 (21)~ was not co~sidcrc.~ feasible to crct~t.e molec~[es of carbon and alone containing more than three earl)on ~t~oms per molecule. had been preI)t~red and found to he ~figh melting ~nd no~ very stable No higher members of this ~Mes bad bec~ identified. The com~o~ fMlacy of analogy led to the expectancy of last.ability for higher moleeula weight compounds of carbon and halogen. Now t]~t, numerous pounds in t.he f!ucroetwbon dom~fin haw~ be(m prepared and studied, are force~biy brought to the reMizatlon that, a.nMogy between chlo~ and fluorine in ehemi(~al compounds is ext~vmeiy hazardous and tha between organic compounds and fluorocarbon compou~xds even mo~ Once it w~s dcm~mstratcd (22) ti~at tluorocarbons cow, raining mot than three carbon aLom~ per molecule wcrc cxt, reme]y stable and tire substances, it was ~ery e~sy to rationalize these properties~ surprisin~ as they were ut that time. Considering th(~ fundamentaI properties bond energies ~nd bond radii (12) shown in Table I, i~ is easy to see tha fluorine atoms are held more firmly to t.he carbon skeleton than are STATE 07525278 3008.0004 FI, ITOROCARlgONS AND T[tEIR PRODUCTION 403 atoms of any other clement. There is an additional factor wllid~ the bond r~dii [ndie;:~{.c t,ut do not. a(lequ~Lcly exi~,’ess. I-Iydrogen atoms surrot~ding the carbon skeleton i~x hydrocarbons in the tetrahedral arrangement do not completely cove~’ an~I p~’otect the carbon atom or the bonds between atoms. A (~om!)letc shclI of chlo~’ine atoms surrounding a carbon skeleton exists u~(ler strains :~nd repulsive forces as the chlorine atoms ~-c too h~cgc for ~hc symrnet.ric~l, sizable structure. A eomptete .covering of fluori~e at()ms over t}~c e:u’l:)on skcic~on apparently form a su~c~ently compact envelope so as to protect both the carbon atoms and the bo~ds (or intcrnal force licld~) from cxpos~m or a~tack from outs~dc moleculeS, without at t.he same time creating undue interaal repulsions. Most c~.~¢mica! reactions of cart)onaecous st;ruc~ures involve attack ~ither at an exposed carl.)on :~tt)m, :~s in the ba(~k side entrance in the WMden inversio~ (n. at exposed l)t~(ls or ft~rcc fields. The compac~ fluorine atom envelop~z in t.he fiu()roca~’l)ons forms such a protective coating fi~a~ the rate of r~acLien is greatly reduced even wader conditions where reactions are allotted o~" favored by thcr~nodynamics. Thus it can be truly stated that ~uo~’ocarhons have he~rts of diamond ~nd skins ef rhinoceros hide. As the fluorocarbons and their derivatives are both much more static thermodym~mically and more resistant structurally to chemical attack ~han a~aIo~ous o~’~anic compoumls, it can be expected that not 0nly can most of ghe structt~res of organic chemistry be duplicated in the fluoro- carbon domain b~t aIso many comi)o~mds not feasible in organic chemis- try can be obt~dncd as stable substances. ~Fhis will permit the creation of a gr~e~ number of coml)ounds in the fluorocarbt)n domain than in organic chemistry. The number of compounds ~,hai. will be prepared tt~at are par~ fln~n’oca~.l)on and part organic becomes enormous~ so much so that, o~r present systems of classifying and arranging will probabl~ not be satisfactory. There are differences between fhmrocarbon compounds and organic compoo~ds theft do not permi~ c()~nplct~cly analogous strnctures in thetwc domains- Compounds containing t~hc grouping R--OH where R is fluorocarbon will not be very stable be(:anse of t.he ready fo~’mati0n of HF. However, this is counterbalanced by the fact that R~()F is st~ble in the fluorocarbon domain bn~ is not in organic chemistry. CFaOF and C~taO~i are stable I)~t not~ CFa(HI or CItaOF. A similar situation may e~:ist for ~ost amines ~.dthough one fluorocarbon compound of f~his type is kno~’o (CFa)~Nt.I. (]ompou~ds of the types RNF~ aad R~NF (deriva- tives of ~trogen trifh~t:rlde) ~rc quit)e stable substances in the fluoro- carbon domain but ~known ir~ o~’ganic chemistry. Dime~hforyI peroxid¢~ CF~OOCFa, has none of the expi~ive instabiliW of dimethyl peroxide- ,Similarly higher’ oxidized types of other kinds witl be found STATE 07525279 3008.0005 STATE 07525280 3008.0006 STATE 07525281 3008.0007 ing the syllable to "for." This also grc~’~,[y improves the sounding the names. This system ht.~s been propose<t (19), ~md Mthough oh~. tions ~o it were req~est,ed, none has been received. This system correspondingly been tu:h)ptcd for this book---mcthfor~ne methforyl (CF~--)-..,-ethforane (C~F~)---.cthforcrm (C~F~)-~methfo~ peroxide (CF~)~O~, Early History Chemists have been interest.cd ira the great reactivity of fluorir~e fror.~ the time Moissan isolated the clement a~d h~vc known it~ power o igniting carbonaceous substances ~ room tcmper~ture or below. san himself found that carbon ~md organic substances caught fire fluorine. He made efforts to isolate the products of the reaction, but characterization of ~bcse w~s w~gue; there was ~m error tff over 1~0~ the boiling point of methforane. As these reactions are extreme~ violent, i~ is no~ surprising ~]mt pure methforanc was not prepared uati 1926 (8). StLbsequent]y tim reaction between t~uori~e a~xd carbon w~ studied more inte~sively. Products from the high-temperature tion between tluoriue and wood c]mvc,ta] i~t :~ hard glass tube were par- tialiy identified (17). These were found to be CF~, SiFt, COz; ~x indefinite condensate boiling -50~ to -2()°C with varying molecuiar weighti and a heavy pleasant smelling tluid boiling over 0~ contaminat~ with HF and H~SiF~.