研 究 論 文 JHlIllMltlHlHlLIHlltlt

Ni trationmechanismofauwlbenzeneswithN O2

by K 批uoFURUKAWA暮,FujirokuYOSHIZAWA●.Yosh iakiAm U' MitsumARAI●andMaSamitSuTAMU RA ●

tnordertoclarifythemechanlsrnforthearomaticnitrationwithNot,Wehve

00rriedoutthenltratlonofalkylben Zene SWithNOBandhavelnvis也gatedtherela - tionshiptxtweenthepar由Iratefactorsandtheelectrondensitiesatthesubs titu- tionpositions,therelationshipbetweenthereladveratesinthecompetitivenltra- tionsofalkylbenzenesandthelonIヱatlonpotentlalsofthesubstrat es,andthesub･ strateselecdvityinthecompetitivenitrationofmesitylene/naphthlene byGalli's method.Asar esul t.thereac也onshouldbeanelecb'Ophillcsubstitudoninvolvinga radicalca也onformedfromtheone･electrontransferprocess,whichshouldbethe rate･determiningstep.

1.Introducb'on reacdonmechanisminvolvingNO2'asanim-

SincedieselexhaustgasiskJIOWntOContain portant a tta c Jdn gSpeci e shasbeensu8 8 eSted. nitrogenoxides(NOx)andpolyaromatichydro･ NIt ro･PAHsareconsideredtobeformedfrom Carbons(PAHs) , thepJ･Oductionornitro ･ thereactioninvolvingSeveralnitrogen o xides

pol押rOmadchydro c arbons(ni tr o-P AHs)h the (NO 24) ,N 20 55･6) ,HNO 37) ,etc･)inthea tmo - exIlauStga s and/or in theatmospheremayOCI sphere･ Al thoughNO 2 isconsideredasoneoE cu r )-3) ･ Thenit r o-PAHscanpossiblybeharTn･ themostimportzLntattacking sp ec iest owdPAN

hlto li vhgorganismduetotheirmut a 8 enicami in thea tmosphere,Onlyafewstu dies havebeen C町 Cinogenlcproperd es4I. T herefore,horder doneconcemingthemechanismforaroma也c tore tardtheformadonofni o-P AH s,itlsnec- tr nitratlontJSingNOz･ essa rytodari fy themechanismfordlearOImdc Rad.ner B) hasreportedthatthenitrationof nitra 6onof PA H wit hNO x･ PAHswithNOBinanonpolarsoLventquan tita･ Ontheo therhand , aroma也c ni tradonwithni l livelyyieldsmononitroIPAlisandther e action tricacidiswell･knowntobeofind 山 地 Iimpor- show edhlghposldonalse lecd vity.PryoretaL 9I tanceasaunitprocessforthesy nth esesof e9L- andSasakiet a l.)Q･117haveattemptedtoclarify plosiv es ,intermediatesofdy es ,medicinesand th emechanismforthearomadcn ltradonwith agricultuJ･alchemicals.Manystudiesonthis NOZintheliquidphas e･sugBeStlngthataone･ reactionhavebeencarriedoutnotonlyinthe electrontransferprocessshouldplay ani mpor- 氏eldsofindus tr ia lchemi str ybutalsointhefield tantroleinthearomaticnitratlon.However. ofphysicalorganicc_hemi stry.Asaresul t, the thedetailedmechanismisstillnotclear. ReceivedonMay 19,199 8 Therefore.wehvestudiedthenitrationof ●DepartmentofChemicalSystemEngineer･ ing,SchoolofEngineering.TheUniversity a叫lbenzieneSwithN O2 inanonpolarsolvent ofToky0 tocladFythemechrLlSmfortheaTOm細 Cmi tra一 713-1 ,Hongp ,臥m kyか ku. T okyo I131 8656, 也oh d thNO之andto Fu rtherob tai nsomeideas Japan T EL +8 1-3-3812-21I1(ext.72 93) Forretarding th eformadonoEnit ro･P A Hsinthe RI X 十81-3 -5 684-3299 atJnOSPhere.

-)60- 火薬学会港 2.E xpen.m e ntal substratesandtheheatsofformationFortheir 2.1Maten'als o-complexeswithNO2andNO2'bythePM3 , . o･,.m ･andp-xylen es ,mesi- method,semトempiricalmolecularorbital tylene,ethylbenZ:ene.CumeneandnaphthaLene methodMOPACver･6 L3 ),andcomparedthem wereusedasthearomaticsubstratesand withtherelativerates. dichloromethaneasthesolven t. 4.Resultsanddiscussion

Thearomadcsubstrates,theirn itroderivadves 4.1N itr ationofalkyrb e nzene anddichloromethanewerepurchasedFrom 4.1.1 Pr oducts WakoPureChemicalIndustries,ud.,Tokyo DuringthenitrationofsubstrateswithNO2, ChemicalIndus tryCo.. ud. ,KantoK a8 aku Co二. therin8･nitratedproductsweremainlypro･ Inc.andFlukaasthehighest coTnmerCialgrade duced.AIdehydesandketonesproducedfrom chemicalsavailableandwereused wi Lhoutf ur一 theoxidationoftheside-Chainsofthesubstrates therpur iJi cadon.2-Ni tmmesitylenewassynth e- werealsodetected.i.i,ben祖IdehydeFromtolu- sizedbyBla tt' smethod lZ J･N zO IWaspurchased ene,tolualdehydefromxylene.andacetophe･ fromTakachiho K agak uK ogyo C0. ,I.td.. nonefromethylbenzeneandcumene.Aswe

2.2Expen'm en talMethod areintereste di JIOnlythering･nitratlon w 仙 NO Z.

AcertainamountoFsubstrateandN 20 1and nofurtherIdentlrICationoftheoxidationprod･ I5mlofdichlorornethanewereintroducedinto uctswasdone.Eachisomerdistributionofthe atbee･necked100mlhskequipped wit hacon･ nng･nitratedproductswassimilartothatforthe denser.memixttJreWasStirredforabout5 nitration wi dlHN O, / H2S Ollll･ ho ur s.T TIereaCdontemperaturewasm a in tained Weobtain ed thepseudo 一氏rst-orderratecon- at15℃. s tantsfortheFormationofring･nitratedprod-

Thealkylbenzene (I.0×10 12 -2.3×1 0ー2 mo l) uctsinthecompetitivenitrationoFsubstrates and1.6× 10~ Imolof.N 20 -(3.2×10- 2 molofN 20. aocordh81oEq.I inordertocalculatetheirrela･ formesitylene)Wereusedforthenit ra tionof liverateconstants (K) andthepartialratefac- eachsu bs trate.Forthe com pe舶 veni tra tionor tors(f/f o). alkylbenZene S,7･2×10 ･3 - Llxl0 -2 molor

3 alk ylbenzene(eDECeptformesitylene),9.4XI0- ･n 盲宝 =kt (I) moloftolueneandl･6 ×1011molorN 20 4Were a:initialconcentrationofsubstrate used.Forthecompetitivenitrationofmesity- x:concentJ.ationofring-nitratedproducts 1ene/p･,I.0×10 -2 molofmesitylene, k:rateconstant L1×10- 2 molofp･xyleneand3･2x10-2molofN 204 t:time wereused.Forthecompetitive nit rationofmesi･ tylene/,1.4×10-2molofeachsu b- Therelativerateconstants,thepartialratefhc･ Strateandl･6x10-2molorN201WereuSed･ torsandthelsomerd istributionsareshownin Substratesandtheirreactionproductswere Table I. directly ex tractedfromthereac也onmixtureat TYIenlb.adonrat e softhealkylben之eneS With differentdmesandanalyzedusingagasC hro- NOZaremuchsmallerthanthosewith H N03/ mato8raph(Shima血uCo l Iid.,G C づA)witha ⅠちSO .HI,e.g qthepseud o-hTSt l0rderrateconstant れameioni姐tiondetector (FID)andbygasChro- forthatofben之eneis2.9×10L 6 5'l.sincethe matograPhy一maSSspectromeby(Shimad乱 IGC- concentradonofNOBisapproximatelyesdmated 14A,GCMS-Q P 1lOOEX)usingastainlesssteel tobe0.02 IS) to o.06MJ6),thesecond･orderrate column(3mrn¢×3mSuiconeOV-lot5%Unipo rt constantforbenzenewouldbe4.8-15×10 ~与 H P60/8 0. GLScienc eshc.). MIIs-I.

3. Calcu Jationm ethod 4.1.2 Effect sofalk y ls ubsdtu en tsonaromatI.c WeCalcu latedtheel ectr onden sid esatthes ub- nitra tionr ates sdtudon･psi也on s, thetonJZadonpten d alsofthe Therelativerateconstantsforthe ni trationof

Kayak uG akkaishi.Vol.59.N o.4. 1998 -Je J- TabtelReladverateconstants.pa rthlratebctorsandisomerdistrlbudons in the nltradonoFalkylbenZens wit hN O2 mol私 trate ReladverateProductPardaJratefacto homerdistrlbudon/ Subs constantK r′㌔ r

1 I-n 触 work ro 3.9×10 52 oluen 2.5×10 O-nit m-nitreitTO 1.8 1 -3

I.7x IO2 p-nitre3-nitro I.8×6.8×10 10 2 45 4-nitro 3.3Xl OZ 356

1.3×10 2 5 9.2×10 2 2.nitro 5 4-nltro5- 2.6xI O3 95

o ･Xyle∩emrxylenep･Ⅹylen ee 2.6XI iI Z 2-n ni tro 0 0

3.6× 10 3 2-nitTOiけo 7.2×l 3.9×10 2 -

3.2×10 m-ni0 -nilrotre 5.5×10O 57} - p-ni 2.3 2

-nitTO 2.1x10 29 2.4×10 m-nitro0 tre 3 7.9×10 41 benzenet p- ni tro 9.6×10 .0 674 ethylbenzeneCumene'Ni mesitylene tra benzene,toluene.xylen lon wit h H NO ,/ 叫SO.1.A) crease inth efoIIowin8Or esandmesitylenede-

Xylene>p･Xylene> o ･Xylen der:mesitylene>m･ gene.Itispostulatedthat e>toluene>ben･ onthearoma也CringshotJ theelectrondensity anincRaSe in thenumberof ldbecomehigher with

S也tutedonthearomadcri ng.r methylgroupssu b 一 cr e as edel ec trophiucnitradon. eTsul血 ginan in一 言 constaJltSfわrthenitration herelativerate ethylben2:eneandcumenea ofben2iene,tOluene . decreasingorder:ethylben2 reinthefouowlng ene>benZ:ene.Ttlsalso :ene≧Cumene,tOlu･ largeralkylgroupshoul postulatedthatthe densityonthearOmadc dinc托aSetheelectron notingelectrophlllc rin8,re Su l血ginpro･ degreeOftheincreasewas nltration･However,the notas fortheintroductionoFrnuldpleme hlghastht ents.Inordertoquan tlta也 vely thyIsubs ti tu- ente ffec tsofalkylgroup esdmatethesubs dtu･ tocomparetheprdalratefact s,wehaveattempted ors d th theel tro ec- tionpotentialsbecausetherelativeratesofthe one-electrontransfershouldbedependenton theenergyleveloftheHOMO(ofthesubsbT ateS) OmesityTene -LUMO(o rNO z) 8ap･Asaresult,therela也ve rateswerefoundtobedependentontheioniza一 ?rTIl･xyzene 也onpotentiaLs(Fig.2).Astheioni2adonpoten - BIene P･ tialissmaller,namely.oneelectronI'se耶ilyr e- 5 5 0 o･xyZene leasedfromthesubstrate . thenitrationrate be･ ethyJberlZene comeslarger･Kowertetal.L97studiedthehom o- b o cumene toluene geneouselectronb･ansferreactionbetweenaro - maticmoleculesandtheirradical仁ationsand indicatedthattheenergyrequiredtoremove oneelectronfromtheparentmoleculeshould 9.19.29.39.49.59.69.79.8 playakeyroJehdetermhingtheelectron tr ans･ ferrate.Kochietal.2D)studiedthearomadcni･ Ionizationpotential/eV trationwithN･nitJ'OPyridiniumcationsand Fig. 2 Relationshipbetweenlogarithmorrate showe d that.thenitrationrateshould bec orre l constantsinthe compeddv e n紬 adonsand latedwiththeHOMO･LUMO gapinthe ioniZadonpote n 血lsorsubs trates 【ArH,XPyNO 2'] complex,suggesting･thatthe mechanismshouldincludeastepwiseprocess thtp o siio n, indicatingt h atthepartialr a tefac ･ t inwhichthesubstJ'ateisselectivelycontrolled torshouldbealmostdependentontJleelectron bythechargetransferprocess.Therefore.the densityatthesiteoE n itro-substitution.Previ- resultshouldsuggestthereac也oninvolvinga ously,SasakietaLshowedfromastudyofthe one-electronreleasefromthesubstrate. subsdt u enteJrectsonthearomadcnitJ･a也on with Fu rthermore･itisreportedthat NO 2Should NO Z thatthearomadc ni tradon wit hNO Zi nCCII react wi ththereducingagentsViatheelecけon should beelectrophilicbasedonanegative transfer ZI) .anditisalsosuggeste dthat theSOMO Hamme tL 'spvalue (-I.7) lI ),andhere.wecan energeylevel 22)of NO 2ト9･75eV)shouldbelow againsuggestthat仙ereactionshouldbeap- enoughtoauowaone･electron transfer & omthe proximatelyel ec trop は1ic ･ AJthou8hitisgen eJ-- substrateto NO 2･Therefore,Wesuggestthe allysuggestedthattheclassicalo-complex possibilityofaone･electrontrmsfermechanism mechanismshouldfavor th eattackatthemost forthearomaticnitratlonwi 山 NO 2･ electronrichpositionsoHhesystem t7) lKeumi 4.2SubstrateselectivitybytheGaHilsmethod etal ･) 8lsug8eStedthatthehi島helectrondensity Inapreviousstudyonthearomaticnitradon atthesu bsd tuentpos紬onshould beresponsible wit hNO 2' .manyargumentshavebeenmade fortheelectrontransfermechanismduringthe aboutthemechanismoFthearomadcnitratlon

nitrationofdibenZ:OfuranwithC(NO 2)./ viaaone･eL ec trontransferpro o e 防 23 )･NaBakura

trInuoroaceticacid/lightexcLuslvelyoccurrln8 eta 1.2 17theoreticauydevelopedontheideaof atthe3･posidonindi ca tingthatthe打Oma也cnil theone･electrontransfermechanism.Further- tradon wit hNO 2may tXelucidatedbytheelec- mo re,perrin ZSIreporte d theone-el ec tron trans- trontransfermechanis m. fermechanismforthereactionbetweenthe 4.1.3SubstrateseLectr'vl'tyl'ncompetitiveni trか naphdlaleneradicalcadonand NO 2 inadlOught･ ぜon provokingardcle･Howev erlitisnoteasytodis･ lnordertoobtainaddi也Onalinformadonon tinguishbetweentheone-electrontransfer themechanismforthearomaticnitra也on with mechanlSmandthecl舶S Lc alo･ oomplexmecha- N ot .WeCOmParedtherelativerateconstants ruSm. during COmPetitivenitrationw仙 theirionlZa･ Here .i nordertoclarifythemechanismfor

Kaya ku 由kkai sh LV d･59･N o･4 ･1998 -J63 - Table2Calculatedioni21ationpotentialsofsubstTateSandstabili之a- donenergl eS OF o･Comple xes

Substrate ⅠP/eV AE如㌔′kJmolー 0 -complexwith NO 2 0 -complex 1 wit hN mesitylene 9.28 -70. O2' naphthalene 8.83 - 5 64.4 a:AEs.Ab ;三H value(q･complex) 56.6 -Hb value(substra te) 69.4 -Hb value

b:CalcuhtedforoICOmplexatl-position(whichls (NO 20r NO 皇+) p predominandy

RO･ ･NO2昔roduce 【d2t )) R@ ･･Nb･)- ( R@ :: .2莞 R& NO2 Scheme 1 Mechanismforthenitra也onofalkylbenZ O-cornplex)

thearomaticrlitrationwit hNO 之. ieneS Wi thNO 2 riedoutcompetitivenitrationusLngGalli' Wehavecar- naphthalenewith N ot1ssomewha q-complexof

th an thatoEmesitylene wit hNO 2, tmorestable methodG aI Iietal.sugge 26). st thatsubstrate s intherelativeratebetweenthe coth edifFqence thecompetitivereacdonofmesit selec dv ityin trationwi thNO 2andthatwi thN mpetitiveni- thalene(substratesinexcess)sho ylene/naph- ableandshouldbeimportant . TO 2'isremark- asaprobetodistinguishbetween uldbeuseful resultsuggeststhatthearomatc herefore , the tron transfermechanismandthecla theone-elec- NO 2Shouldbeelucidatedbyan nitra也on with plexmechanismduringelectrop ssic alo･com- processinvolvingaradicalca也o electrophilic substitution.Sincemesityleneha huicaromatic one-electrontransf er,whichshould nformedbya basicitythannaphthaLene.mesi sahigher o- determiningstep (Scheme 1). betherate･ haveahigherreactivit y thanma tyleneshould theclassic alo-complexsubsdtuti phthalenefor 5. lnordertoclarifythemechanisConclusion

Sincenaphthalenecanbemoreea onmechanism. Tnaticnitration wit hNO 2,Wehav mfor the a m ･ toaradicalca也on th anme sitylene silyoxidize d nitrationofalkylben2:ene Swit hNO estudiedthe shouldhavehigherreactivityth ,naphthalene larsolvent.Asares ult,thereac也on …inanon po- fortheone･electrontransfersubsd anmesitylene trophilicsubstitutionandtherate wasanelec- nism. Th eionizationpotentialsan tutionmecha･ waschiemydependentontheele ofnitration za也onenergiesofthe a-compl dthestab ili･ atthesubstitutionposition.Du ctrondensity andwit hNO 2'foreachsubstrate exeareshovswith NO 2 pet itive'ni tra也onofalkylbenZene S,ringthecom･ selectivitywasshowntobedep thesubstrate Table Inthecompetitivenitrationof 2. m in ioniZadonpoten也also E th emienton the naphthalene ,2 -mitromesitylene mesitylene / m e00n p 触ve nitra tionofmtsit esubs trates. nitronaphthalenesweremainly and I- and 2- thalenehasalsobedoneusingGa ylene/naph･ therelativeformadonrateof K Aproduced.andIE Duringthecompe鵬veni tra donof lli'smethod. (1･4土 0･ 1)× loll.1tissigni B cantly S/K NAPH Was naphthalene ,NO 2predominantly mesitylene / therelativeformationrateof different血･om naphthaleneresul tingintheproduc也 reactedwith 20士1 26) dLdngthenitradon wi thNO K MES /K NAPH 岩 2lnitronaphthaLene ･Th eselecti onof I- and indicatesthattheoneelectron-tr 2十･ Thisfact differentfro n thatofthenitrati vitywasmuch nismshouldplayanimportantr ansfermecha. ol e. AIthough thestabilizationenergyforthe Basedon theseresul ts,Ⅰtcanbes onwithugg este dNOthat 2+I thenitradonofaLkylbenヱene S Wit hNO2Should 13)MOPACVer.6.0.∫.J.P.Stew ar t,QCPE#455; beelucidated by themechanisminvolvingaradi･ RevisedasVer･6･01byTsuneoHirano , Gal仁ationformedfromtheone-electrontrans- OchanomizuU n iversi ty,forHnnCmachine, ferprocess.whichshould bether ate-determin･ JCPENewsletter,2,26(1991 ) lngSteP･ )4 )(a) K Schorleld ,"A romaticNitration" ,C am･ R曲rences bridgeUniversityPress ,London(1980); I)T.aHenderson.J.D.Sun .RE.Rover,C. R. (b)G･A･ 0 1ah ,a MalhotraandS.C.Narang , Clark ,A.P. U .T.M.HaⅣey,D.H.Hunt,∫. "NirationMethodsandMechanisms".VCH . E.Fulford.A.M.Lovette,andW.R. NewYork(1989) Davidson,Environ.Sci.Techno 1., 17 ,443 15)T.Wakabayashi,T.Yoshida,andK.Nanba, (19 83) Kogyoぬyaku,35,70(1974) 2)I.M.Bayona ,K E･Markides.andM ･L Lee . 16)K.Y.Lee,C.Amatore,andI.KKochi.J. Environ.Sci.Techno 1., 22,1440(1988) Phys.Chem.,95,1285(1991 ) 3)H.Kachi.Anz:enKoga ku,27,373(1988) 17)I.Fen 8, X.Zheng,andM.C.Zerner,J.Org. 4)H.Tokiwa,TaikiOsenGakkaishi,27(2),73 Chem.,51,4531(1986) (1992) )8)T.Keumi.K.Hamanaka,H.Hasegawa,N. 5)B.ZieJins ka,I.Arey .andR.Atkinson.J. Am. Min amide,YJnoue,andH. 氾tajima,Chem. Chem.Soc.,108,4126(1986) Lett.,pp.12 85 (19 88) 6)∫.N.Pit ts,B.Zielinska,∫.A.Sweetman,氏. 19)B.A.Ko叩e rt, LMarco ux.andA.∫.･Bard,I. Atkinson,andA.M.Winer,Envion.Sci. Am. Chem.So c.,94,5538(1972) Techno1..19.Ill s(19 85) 20)E. K Kin ,K Y.Lee,andI.KKochi,I.Am. 7)A.M.Kames,J.Guo,Z.Guo,andS.R. Chem.Soc.,114,1756(1992) McDow,Atmos.Environ.,24A,1161(1990) ●21)H.Kobayashi,N.Takezawa,andT.Niki , 8)P.Radner,ActaChem.Scand.,837,65(1983) Envion.Sci.TechnoL,1l,190(1977) 9)W.A.Pryor.G.I.Gleicher,J.P.Cosgrove. 22)V.H.Dibeler,∫ ,A .Walker,andS. K Liston, andD.F.Church,∫.Org.Chem.,49,5189 J.Res.Nat.t∋ur.Stand.,71A,371(1967) (19 84) 23) LEberson,andF.Radner,Ace.Chem.Res., 10)Y.Akutsu;M.Sasaki,T.Saito,M.Tamura. 20,53(1987) andT.Yoshida ,K ogyo Kayak u.51,61(1990) 24)S.Nagakt m , andI.Tana ka,B山LChem.Soc. ll)M.Sasaki,Y.Akdtsu,M.Arai,andM. Jpn.,32,734(1959) Tamura ,K ogyo Ibya ku,53,121(1992) 25 )C. LPerrin,J. Am ChemS oc.,99, 5516 (1 977) 12)A.H.Bla tt,O r苫a nicSy nth esisCoIIediveVol- 26)C.G all j.andS.D.Giammarino,J.Chem.Soc. ume2,JohnWiley&Sons ,Inc.,p449(1943) Perkin ≠ans.2,1261(1994)

Kayaku G akkaishi･VoL59･N o･4 ･1998 -165 - N0 2によるアルキルベンゼンのニ トロ化反応に関する研究

舌川音久夫●,古沢二千六●.阿久津好明● 新井 充●,.田村昌三●

N0 2による芳香族ニ トロ化反応に関する基鮭的知見を得るため ･N0 2によるアルキルベン ゼンのニ トロ化反応を行い,反応脚 について検 討した｡その活魚 基質の置換位置の電子 密度 と部分速度因子との比故から,反応は求電子的侯向を示し,また基質間相対反応速度と ィォン化ポテンシャルとの相関や,Ga uiの方法によるメシチレン/ナフタレン競争反応の検 討か ら.反応は-亀子移動過程を含むラジか t,カチオンが関与する機構で進行する可雛 が 示された｡ (･東京大学大学院工学系研究科化学システム工学専攻 〒 113→8656 菓京都文京区 本称7-3-1)

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