Sechinyakare, catalyst inoshanda nekudyidzana kwakananga nemareactants.Mune itsva noncontact catalytic system (NCCS), yepakati inogadzirwa neimwe catalytic reaction inoshanda semurevereri kuitira kuti mhinduro yakazvimirira ienderere mberi.Muenzaniso ndeyekusarudza oxidation ye ethylbenzene, iyo yaisagona kuitika pamberi peimwe solubilized Au nanoclusters kana cyclooctene, asi yakaenderera nyore apo vese varipo panguva imwe chete.Iyo Au-initiated inosarudza epoxidation ye cyclooctene yakagadzirwa cyclooctenyl peroxy uye oxy radicals iyo yakashanda sevamiriri kuti vatange iyo ethylbenzene oxidation.Iyi yakasanganiswa sisitimu yakawedzera zvinobudirira maitiro eAu.Maitiro ekuita akatsigirwa ne reaction kinetics uye spin trap kuyedza.NCCS inogonesa maitiro akafanana kuti aenderere mberi pasina zvipingaidzo zvehukama hwe stoichiometric, ichipa madhigirii matsva erusununguko mumaindasitiri ehydrocarbon co-oxidation maitiro.

Nechinyakare, chinokonzeresa chinopindirana zvakananga neanogadzirisa (reaction A) kuita bond rearrangements inotarwa nemaitiro.Semuyenzaniso, mucobalt-catalyzed oxidation yealkylaromatics (1) kana iyo Au-catalyzed epoxidation ye cyclooctene (2), iyo catalyst inofambisa kubviswa kweatomu rehydrogen kubva muhydrocarbon kuti itange kuita.Mune yemahara radical chain reaction, a catalyst anotora chikamu mune catalytic homolytic cleavage yechisungo chisina kusimba mune yekutanga iyo inowedzerwa nemaune kana iripo seyakaipa tsvina mumusanganiswa wekuita (1, 3, 4).Mamwe nhanho mune inokonzeresa tandem reaction inogona kusada yakananga substrate-catalyst kuonana kana shanduko ye substrate ichigoneswa nechigadzirwa chakagadzirwa zvine hukasha mumatanho apfuura (5-8).Nekudaro, maitiro aya anomanikidzwa nehukama hwe stoichiometric pakati pematanho.Semuenzaniso, muMukaiyama (ep) oxidation yealkene, catalyst inoshandura chibairo chekudzikisa mukuita A, yakadai se isobutyraldehyde, pamwe chete ne stoichiometric kugadzirwa kwe epoxide (reaction B) (9, 10).Kunyange zvazvo zvichibvira mumusimboti, isu hatisi kuziva muenzaniso wekuti basa rechinhu chinokonzeresa kubudisa S pakati pekuita A, apo S inoshanda semurevereri kuti atange kana kukonzera imwe mhinduro B pane kutora chikamu se stoichiometric reagent. , nepo iyo catalyst isingabatsiri pakuita B (Fig. 1).Muchirongwa chakadaro, pesvedzero yecatalyst inotambanudzirwa kupfuura catalyzing reaction A kusvika pakuita reaction B asi pasina kudhumana zvakanangana nemareactants ayo.Isu tinodaidza chirongwa chakadaro kuti noncontact catalytic system (NCCS).MuNCCS, zviyero zvekuitwa kwemaitiro A uye B hazvina kusungwa nehukama hwe stoichiometric pakati pavo.Izvi zvakasiyana nemaitiro etandem.Muindasitiri, hukama hwakadaro hwe stoichiometric hunowanzoisa zvipingamupinyi zvehupfumi pane kugadzirwa kwemakemikari.Muenzaniso unozivikanwa ndeye stoichiometric kugadzirwa kwe phenol uye acetone ne oxidation ye benzene kuburikidza ne cumene hydroperoxide yepakati mu cumene process (11).

A catalyst (Katsi) inokonzeresa kuita A (AR ➔ S ➔AP) iyo yepakati S inoshanda mukutanga kana kukonzeresa kuita B (BR ➔ BP), kunyangwe kuita B kusingakonzereki nekatani.

Takawana NCCS yakadai patinenge tichiongorora zvinokonzeresa zvivakwa zve solubilized Aun masumbu (apo n aiwanzoita matanhatu kusvika masere maatomu) echikamu oxidation ye ethylbenzene (EB).Isu takaratidza kuti idzi solubilized Aun dzakakonzeresa kutangwa kwekusarudza epoxidation ye cyclooctene (cC8═) neO2 ine ~ 80% selectivity (2).Aya masumbu akaumbwa mu situ panguva yeAu/SiO2-catalyzed cC8═ epoxidation, uye vakachengetedza kugona kwavo kugadzira iyo radical initiator cyclooctene hydroperoxy radical (cC8═OO ·) mukati mekuita.Iwo solubilized Aun masumbu anogona kuunganidzwa mumusanganiswa wekuita mushure mekubviswa kweAu/SiO2, uye avhareji saizi yakatemerwa uchishandisa aberration-yakagadziriswa electron microscopy uye fluorescence spectroscopy (2).Pamusoro peAun masumbu, aya masanganiswa aivewo necyclooctene hydroperoxide (cC8═OOH) uye oxidation zvigadzirwa cyclooctene epoxide, cyclooctenol, uye cyclooctenone.cC8═OOH yaive yakagadzika hydrogenated fomu ye cC8═OO· uye iripo pakudzika kwe0.2 kusvika 0.5 M mushure me40 kusvika 100% cC8═ shanduko.Musanganiswa uyu unonzi Au + cC8═OOH-x, uko x ndiyo muzana cC8═ shanduko.Kunyange zvazvo pamwero wakaderera zvikuru uye nenguva yakareba (> 5 maawa) induction period, cC8═ epoxidation inogonawo kuitika ne auto-oxidation pasina Aun masumbu.Misanganiswa inowanikwa neauto-oxidation isina Au inonzi cC8═OOH-x.MuNCCS, iyo Solubilized Aun yaizove inokonzeresa, epoxidation ye cC8═ inenge iri reaction A, uye cC8═OO· ingave S.

Iyo auto-oxidation yeEB haina kuitika nyore.Pa145 ° C, 9% chete maitiro akaitika kune yakatsvinda EB pasi pe2.76 MPa O2 (12).Pasi pemamiriro edu akapfava zvikuru e100 ° C uye kubvongodza O2 pa 0.1 MPa, pakanga pasina maitiro aionekwa eEB yakatsvinda kweanenge maawa makumi maviri.Kuwedzerwa kwemahara radical initiator kwaidiwa kuti kuita uku kuenderere mberi.Kutanga ne 2,2′-azobisisobutyronitrile (AIBN), yakanyanya reactive thermal radical initiator, yakakonzera auto-oxidation yeEB ine avhareji chetani urefu hwe ~ 3 (fig. S2A).Cheni ipfupi (~ 1) yakaonekwa ichishandisa isingaite tert-butyl hydroperoxide (fig. S2B), uye pakanga paine zvishoma zvinoonekwa maitiro uchishandisa ishoma inoshanda cumene hydroperoxide.Nekudaro, auto-oxidation yeEB haina pesvedzero pamhinduro dzakataurwa pazasi.

A aerobic oxidation yakadzikama yeEB kusvika kuEB hydroperoxide, acetophenone, uye phenylethanol yakawanikwa nekuwedzera Au + cC8═OOH-50 ine musanganiswa weAun, cC8═OOH, uye cC8═ isina kugadziriswa (Fig. 2, curve 1).Sezvinoratidzwa nekuedza kunotevera, zvikamu zvitatu izvi zvakatamba mabasa makuru muEB oxidation, uye yaienderana necatalyst, S, uye AR muNCCS system inoratidzwa muFig.

(i) 7 ml yeEB + 3 ml yeAu + cC8═OOH-50;(ii) 7 ml yeEB + 3 ml yeAu + cC8═OOH-50 + 1.2 mmol Ph3;(iii) 7 ml yeEB + 3 ml yeAu + cC8═OOH-99 + 0.6 mmol Ph3;(iv) 7 ml yeEB + 3 ml ye cC8═OOH-50;(v) 7 ml yeEB + 3 ml ye cC8═OOH-50 + 1.5 mmol Ph3.Huwandu hwePPh3 hwakawedzerwa hwakagadzirirwa kuenzana nehuwandu hwetitrated hydroperoxide (tembiricha yekupindura, 100 ° C).

Pasi pemamiriro edu ezvinhu, hapana inoonekwa aerobic EB oxidation yakaitika mumusanganiswa we cC8═ uye EB (kureva, pasina Katsi kana S).Triphenylphosphine (PPh3) inoshanda zvakanyanya mukubvisa hydroperoxides.A Au + cC8═OOH-99 mhinduro, yakapera cC8═OOH nePPh3 yekuwedzera, ine Aun uye shoma shoma isina kubatwa cC8═, yakundikana kutanga EB reaction kunyangwe mushure memaawa maviri (Fig. 2, curve 3), zvichiratidza kuti Aun zvoga zvaisashanda.Ichi chigumisiro chakaratidzawo kuti zvimwe zvigadzirwa zve cC8═ oxidation, zvakadai se cyclooctene epoxide, cyclooctene doro, kana ketone, hazvina kukwanisa kutanga EB oxidation.Kusiyana nekuedza kuri pamusoro apa, kubviswa kwecC8═OOH nePPh3 kubva kuAu + cC8═OOH-50, kusiya Aun uye kusagadziriswa cC8═, hakuna kukanganisa EB kutendeuka (enzanisa curves 1 uye 2, Fig. 2).

Aya matatu matatu e data akakurudzira synergism pakati peAun uye isina kubatwa cC8═ mukutanga kweEB oxidation.Isu takafungidzira kuti Aun yakakonzera oxidation ye cC8═ kuita cC8═OOH, yaive yekutanga yeEB reaction.Izvi zvinogona kuongororwa nekuenzanisa kugona kwekutanga EB oxidation nemusanganiswa we cC8═OOH uye cC8═ asi pasina Aun pamberi uye mushure mekubviswa kwecC8═OOH nePPh3.Kuti titevedzere zvakanyanya mamiriro ekutanga seti yekuyedza, takashandisa mhinduro cC8═OOH-50 yemusanganiswa wecC8═OOH uye cC8═ kuitira kuti chero mhedzisiro yecC8═ epoxidation zvigadzirwa zvigadziriswe.Zvigumisiro zvakaratidza kuti pamberi pe cC8═OOH-50, EB yakaita zvakanaka (Fig. 2, curve 4).Nekudaro, kana cC8═OOH yakabviswa nePPh3, pakanga pasina chekuita kweawa yekutanga uye yakadzvanyirirwa chiitiko chinotevera (curve 5).Iyi data yakawedzera kutsigira modhi yekuti basa rekuita raAun raive rekuramba richigadzira cC8═OOH kuburikidza necC8═ oxidation, uye cC8═OOH yakatanga iyo EB reaction.Basa rekuita raAun rakasimbiswa zvakare nekucherechedza kuti mazinga ekutanga eEB oxidation pasina cC8═OOH yakawedzera nekuwedzera Aun concentration (fig. S3).

Basa rakasiyana-siyana raAun muNCCS iyi rakaratidzwa nekuongorora Co seimwe nzira inokonzeresa, iyo yakasarudzwa nekuti cobalt acetate uye cobalt cycloalkanecarboxylate (13) maindasitiri anokurudzira kushandura EB kuita acetophenone ine molecular O2, inoshanda pasi pemamiriro akaomarara uye inoda kuvapo kweasidhi uye bromide ions.Co complexes inoshandiswawo pakusarudza aerobic EB oxidation muhupo hwe organocatalyst N-hydroxyphthalimide (NHPI) kana chibayiro reductant (14, 15).Nekudaro, pasi pemamiriro edu ekuita, kuvepo kweCo/ZSM-5 hakuna kukonzeresa chero kuoneka oxidation yeEB, cC8═, kana musanganiswa wavo kweinenge maawa matanhatu.Kureva kuti, Co chete haina kukwanisa kutanga kana oxidation reaction.Nekudaro, pamberi pevaviri Aun uye cC8═, yakafambisa maitiro eiyo oxidation.Zvichienderana nemamiriro ezvinhu, cC8═ kana EB yakakurumidza kuita katatu kusvika kashanu apo Co/ZSM-5 yakanga iripo, uye kusimudzira kwakawedzera nehuwandu hweCo/ZSM-5 (tafura S2, zviedzo 6 kusvika 8).Iyo EB oxidation chigadzirwa kugovera zvakare yakachinja neimwe nzira pamberi peCo/ZSM-5.Kuwedzera huwandu hweCo/ZSM-5 kwakawedzera goho reacetophenone uye, zvishoma, phenylethanol goho pamutengo weEB hydroperoxide (tafura S3, miedzo 6 kusvika 8), zvinoenderana nekuti Co catalyzed decomposition yeEB hydroperoxide kusvika. acetophenone uye phenylethanol uye oxidation yekupedzisira kune acetophenone.Nekuda kwekukurumidza, takabatanidza Co/ZSM-5 mumusanganiswa wedu wekuita kupfupisa nguva yekuita.

Chinhu chinosiyanisa pakati peNCCS uye tandem reaction systems ndechokuti mune yekare, hapana hukama hwe stoichiometric pakati pekuita A uye B (Fig. 1).Kusimbisa kuti maitiro edu akaitika kuburikidza neNCCS, takaedza mhedzisiro yekushandura reshiyo yecC8═ kuenda kuEB nekutarisa maitiro avo ega ega.Mufananidzo 3 unoratidza mhedzisiro yekushandura yekutanga cC8═ kusungwa uchichengeta yekutanga EB yekumisikidza uye mamwe maitiro ekuita anogara aripo.Iyo data inoratidza kuti pakanga pasina hukama hwakagadziriswa hwe stoichiometric pakati pehuwandu hwevaviri vakapindura vakaita, vachisimbisa kuti maitiro ekuita akasiyana kubva kune echinyakare tandem reaction scheme.Iyo inofananidzwa seti yezviedzo umo yekutanga EB kutariswa kwakasiyana apo kugadzirisa kumwe kuisa kwakasvika pamhedziso imwechete.Kubva pane idzi data, maitiro ekutanga maitiro akaverengwa (Tafura 1 uye tafura S2, miedzo 4 uye 5) uye inoratidzwa kuti inosiyana zvakasiyana kune cC8═ uye EB.Pakanga pasina kutengeserana kwemitengo pakati pemaitiro maviri aya zvekuti kana imwe mhinduro yaienda nekukurumidza, imwe yacho yaifanira kunonoka zvakaenzana.Ose maitiro ekuita mareti anogona kuwedzera panguva imwe chete, sezvinoratidzwa nekuedza 4 uye 5 mutafura S2.Kutengeserana kwaizotarisirwa kana EB ne cC8═ vakakwikwidzana kune imwechete catalytic reaction saiti kana yepakati.Mhedziso iyi inopindiranawo nenyaya yekuti maitiro epanguva imwe chete eEB necC8═ akange asina kana diki zvakanyanya pakugovera kwavo chigadzirwa, sezvakaratidzwa muTable 1 uye tafura S3.

Yekutanga cC8═ concentrations yaive 0.34 M (A), 1.05 M (B), uye 1.75 M (C).Decane yakashandiswa kugadzira mutsauko wehuwandu hwecC8═ yakashandiswa.Mamwe mamiriro: 32 mg yeCo/ZSM5, 100°C.

Iyi data inopindirana nechirongwa chemagetsi chinoratidzwa muFig. 4, umo matanho anokosha kuNCCS anosimbiswa uye vatambi vakuru vanosimbiswa (imwe chirongwa chakazara chinoratidzwa mufig. S8).Muchigadziriso ichi, maAun masumbu anotanga cC8═ epoxidation cycle nekugadzira cyclooctenyl radicals (I) uye cyclooctene peroxy radicals (II).Aya maviri radicals anobva atora chikamu mu cC8═ epoxidation cycle, sezvakasimbiswa kare (2, 16).Kana EB iripo, II inova molecule yepakati uye inovhara pakati pe cC8═ epoxidation cycle uye EB oxidation cycle.Muchikamu cheEB, II inopindirana neEB kuti iite phenylethyl radical, iyo pakarepo inoumba phenylethyl peroxy radical (III) nekuita neO2, sezvo carbon-centered radical reactions neO2 inozivikanwa kuva yakanyanya nyore (1).Inotevera hydrogen abstraction neIII inoumba phenylethyl hydroperoxide uye pakupedzisira acetophenone uye phenylethanol.III inogonawo kuita nekukurumidza ne cC8═, inova nzira yekuzadza II iyo inopedzwa neEB oxidation cycle.Nekudaro, iyo EB oxidation reaction haina kuperekedzwa ne stoichiometric kudzvanywa kwe cC8═ epoxidation reaction, uye hapana "kutengeserana" mukuita mazinga eEB uye cC8═ sezvaizotarisirwa kana ivo vakakwikwidza kune imwechete reagent. kana catalytic inoshanda saiti.Nekuti II inotora chikamu mudanho rekutanga mune ese EB uye cC8═ oxidation cycles asi kwete zvakananga mumatanho ekugadzirwa kwechigadzirwa, kubatanidzwa kwayo kwemabatiro maviri hakukanganise kugoverwa kwechigadzirwa.

Cyclooctene peroxy radical (II) ndiye murevereri mukuru anotanga iyo EB oxidation.II inogona kuvandudzwa nekuita kweEB peroxy radical (III) ine cC8═.Kumusoro kuruboshwe, Aun masumbu anotanga cC8═ epoxidation cycle (kutenderera kuruboshwe).Kutenderera kurudyi kunoratidza matanho eEB oxidation.Chete matanho makuru akakosha eNCCS anoratidzwa.

Kuti tione kuumbwa kwezvinopindirana zvepakati-kati sezvakarongwa muFig. 4, takawedzera spin trap 5,5-dimethyl-1-pyrroline N-oxide (DMPO) kumusanganiswa wekuita kuti uite kwenguva yakareba nitroxide radical spin adducts ne emahara radicals aripo kuti aonekwe neX-band erekitironi paramagnetic resonance (EPR) spectroscopy.Sekutonga, hapana radicals yakabatwa neDMPO mune mhinduro yeacetone uye decane pasina C8═ kana EB (fig. S4-3).Pakaiswa DMPO kumusanganiswa wekuita musanganiswa une cC8═OOH uye cC8═ (fig. S4-1), mhedzisiro yeEPR spectrum yakanyatso edzerwa sehuwandu hwemhando huru dzakasiyana dzeparamagnetic (A pamufananidzo, ~86% yehuwandu. simulation intensity) uye zvipenyu zviviri zvidiki (B uye C, ~ 5 uye ~ 9% yehuwandu hwekunyepedzera kusimba, zvichiteerana), zvichipa humbowo hwakananga hwekuumbwa kwakanyanya panguva yekuita.Pahwaro hwekuenzaniswa kweiyo hyperfine coupling values ​​kune avo vanozivikanwa DMPO adducts (tafura S1), mhando C yakapihwa kune DMPO/ROO• adduct, zvinonzwisisika iyo cyclooctene 3-peroxy radical (II) inoratidzwa semurevereri pakati pezviviri izvi. maitiro (Fig. 4).Zvisikwa A neB zvakaiswa kune maviri akati siyanei DMPO/RO• adducts, apo R aireva kune hydrocarbon moiety.Inogona kuva imwe yemhando yeRO• inotsanangurwa muFig. 4 kana alkoxy radicals inogadzirwa kubva kuDMPO/ROO• adduct decay [DMPO/ROO• adducts inozivikanwa seisina kugadzikana uye inoora kune inoenderana alkoxy radical adduct (17, 18)] kana musanganiswa wezvose.EB payakasanganisirwawo mumusanganiswa wekuita, mhedzisiro yeEPR spectrum yakateedzerwa nemhando zhinji A′, iyo yaive yakafanana nemhando A (DMPO/RO•), uye maviri emarudzi madiki B neC ane mipiro midiki yakafanana. (muonde S4-2 uye tafura S1).Nekuti kuiswa kweEB kwaitarisirwa kufambisa kuumbwa kwe phenylethyl peroxy radicals (III), mhando A′ ingangove musanganiswa weRO• inogadzirwa mukuita pamwe nechero phenylethyl peroxy adduct, iyo yakazoora kune phenylethyl oxy DMPO adduct.

Kushandisa EB-d10 seyakagadziriswa uye yekutarisa deuterium labeling mucC8═ zvigadzirwa zvinogona kuona kana paine kuita kweEB ne cC8═ based carbon radicals.Migumisiro yekuedza kwakadaro yakaratidza kuti pakanga pasina deuterium incorporation mu cyclooctene epoxide (maonde S5 uye S6).Phenylethanol yakachengeta yese deuterium muEB reactant, uye mamwe ma deuteron ari mumethyl group yeacetophenone akange achinjana, izvo zvinogona kuitika mune mass spectrometer.Saka, pakanga pasina humbowo hwekuita pakati peEB-d10 uye cyclooctenyl radical, iyo yaizounza deuteron mucC8═ zvigadzirwa.

Iko kushandiswa kwechirongwa cheNCCS chakawedzerwa kuti chiongorore Au + cC8═OOH-100-yakabatsira aerobic oxidation ye4-methylanisole.Nekuda kweakasimba ekutanga C─H zvisungo mumorekuru iyi, iyo oxy-functionalization reaction yakaitwa pane tembiricha yepamusoro.Maitiro ekutanga ekushandurwa kwe4-methylanisole ku4-anisaldehyde akafananidzwa nekuita kwakatangwa naAun uye pamwe kana pasina cC8═ kuwedzera (cC8═OOH yakabviswa nePPh3).Zvakafanana neEB oxidation, apo musanganiswa wekuita waive usina cC8═ uye pasina cC8═OOH, iyo yekutanga oxidation rate yainonoka (fig. S7).Kana cC8═ yakawedzerwa kumusanganiswa wekuita, iyo yekutanga oxidation mwero wakawedzera zvinooneka.Nokudaro, maAun masumbu akakwanisa kugadzira cC8═OOH kubva kune yakawedzerwa cC8═ kuti atange oxidation ye4-methylanisole sezvaitarisirwa muNCCS.

Mukupedzisa, isu takaratidza pfungwa yeNCCS.Kushandisa panguva imwecheteyo oxidation ye cyclooctene uye EB pamwe ne cyclooctene uye 4-methylanisole, NCCS yakaratidzwa kugonesa co-oxidation yemahydrocarbon pasina hukama hwe stoichiometric hwemaitiro echinyakare co-oxidation.Izvi zvinopa dhigirii yaimbove isingawanikwe yerusununguko mukuita kwemaindasitiri zvekuti maitiro ehupfumi haachasungwa nekudiwa kwemisika yakanaka yezvigadzirwa zvinogadzirwa muhuwandu hwe stoichiometric.

Zvitubu uye kucheneswa kwemakemikari akashandiswa aive akadai: HAuCl4•3H2O (≥99.9% trace metals base, Sigma-Aldrich), fumed silica (CAB-O-SIL90, Cabot Corporation), ethylenediamine (≥99% ReagentPlus, Sigma-Aldrich) , ethanol (200 giredhi, Decon Labs), cobalt(II) nitrate hexahydrate (≥98%, Sigma-Aldrich), Nano H-ZSM-5 (P-26, ACS Material), decane (≥99% ReagentPlus, Sigma- Aldrich), dodecane (≥99% ReagentPlus, Sigma-Aldrich), cis-cyclooctene (95%, Alfa Aesar), EB (99.8% anhydrous, Sigma-Aldrich), EB-d10 (99 atomic % D, Sigma-Aldrich) , 4-methylanisole (99%, Sigma-Aldrich), acetophenone (99% ReagentPlus, Sigma-Aldrich), 1-phenylethanol (98%, Sigma-Aldrich), hydrogen peroxide (30% aqueous solution, Fisher Chemical), potassium hydroxide (reagent giredhi, 90%, Sigma-Aldrich), sodium sulfate (Food Chemicals Codex/United States Pharmacopeia–grade, Fisher Chemical), tetrahydrofuran (>99%, Sigma-Aldrich), tert-butyl hydroperoxide (~5.5 M in decane , Sigma-Aldrich), PPh3 (> 98.5%, Sigma-Aldrich), d-chloroform (99.8 atomic % D, Sigma-Aldrich), HCl (38% w/w, Fisher Chemical), HNO3 (68 kusvika 70% w / w, Fisher Chemical), EM Quant peroxide test strips, uye sirinji sefa (polyvinylidene difluoride membrane, 0.25 mm / 0.2 μm, Acrodisc).

Au/SiO2.Iyo silica-inotsigirwa negoridhe nanoparticle catalyst yakagadzirwa neAu (en) 2Cl3 precursor zvinoenderana nenzira yakagadziriswa naZhu et al.(19) uye yakagadziridzwa naQian et al.(2).Kuti zvive zvakanyatsojeka, mushonga weAu(III) chloride trihydrate wakagadzirwa nekunyungudutsa 0.5 g yeHAuCl4 • 3H2O mumusanganiswa une 10 ml ethanol uye 2 ml yemvura.Mushure mekugadzira mhinduro ine homogeneous, 0.23 ml ye ethylenediamine (en = ethylenediamine) yakawedzerwa kune mhinduro dropwise kuti iite Au (III) ethylenediamine chloride [Au (en) 2Cl3] ne ligand exchange.Iyo as-formed Au(en)2Cl3 yakaunganidzwa nekusefa uye yakashambidzwa ne300 ml ethanol.Kuisa Au parutsigiro rwesilica, 4.2 mM Au(en)2Cl3 aqueous solution yakagadzirwa nekunyungudutsa 46.3 mg yeAu(en)2Cl3 mu26 ml yemvura yakadirwa deionized (DDI).Iyo se-yakagadzirwa mhinduro yakachengetwa pa40 ° C mubhati remafuta.Zvadaro, 1 g yefumed silica yakawedzerwa kune preheated solution ichikurudzira.Kamwe zvese zvinotsigira silica zvakanyudzwa mumushonga, musanganiswa wacho wakabviswa kubva mubhati remafuta uye wakatonhodzwa kusvika pakupisa.Nekugadzirisa pH yemusanganiswa kusvika pa9 nekuwedzera kudonhedza kwe0.75 M en aqueous solution, kushambadza kurinani kweiyo cationic goridhe macomplexes kunzvimbo yakachajirwa zvisina kunaka yakawanikwa.Mushure mokukurudzira kwemaawa maviri pakupisa kwekamuri, musanganiswa wacho wakasvibiswa uye wakashambidzwa ne500 ml yeDDI mvura.Kubvisa zvisaririra zvisingadiwi (Cl, en, kumwe kusvibiswa), keke resefa rakaparadzirwa zvakare mu200 ml yeDDI mvura pa40°C.Pakupedzisira, iyo-yakaumbwa Au / SiO2 yakaunganidzwa nekusefa uye yakashambidzwa neimwe 500 ml yemvura yeDDI uye yakaomeswa mumhepo usiku hwose.Kuverengerwa kwesilica-inotsigirwa negoridhe nanoparticles catalyst yakaitwa muU-chubhu pasi peO2/O3 kuyerera (~ 300 ml/min) ine ramping rate ye0.12°C/min kusvika 150°C.Iyo catalyst yakachengetwa murima pa5°C.Kurodha goridhe, sekuyerwa kwaiitwa inductively yakabatanidzwa plasma optical emission spectrometry, yaive 1.2 huremu% (wt%), uye avhareji saizi yegoridhe yakayerwa nescanning transmission electron microscopy (STEM) yaive yakatenderedza 2 nm.

Co/ZSM-5.Nano H-ZSM-5 yakaverengerwa muU-tube pasi peO2/O3 kuyerera (~300 ml/min) ine ramping rate ye2°C/min kusvika 200°C uye yakabatwa pa200°C kweawa imwe kubvisa. zvakasara matemplate.Co/ZSM-5 yakagadzirwa nekunyorova kwekutanga.Semuenzaniso, 5 wt % loading Co/ZSM-5 yakagadzirirwa nekuwedzera 0.72 M cobalt (II) nitrate solution [250 mg ye cobalt (II) nitrate hexahydrate mu 1.2 ml yeDDI mvura] kusvika 1 g ye nano H- ZSM-5 uchinyatsotenderedza beaker.Iyo slurry yakaomeswa pasi pemwenje, uye yunifomu yepinki poda yakaumbwa.Iyo se-yakaumbwa poda yakabva yatakurwa mune yakatwasuka calcination chubhu uye yakacheneswa pasi peargon kuyerera (100 ml / min) kweawa 1 kuderedza hunyoro.Iyo se-yakagadzirirwa catalyst yakabva yaverengerwa pasi peokisijeni inoyerera (60 ml / min) ine ramping rate ye10 ° C / min kusvika 450 ° (yakabatwa pa250 ° C, 350 ° C, uye 450 ° C kweawa imwe neimwe) .Iyo yakawanikwa Co/ZSM-5 ine cobalt yakarodha ye5 wt%.Mamwe maviri akaremerwa, 3 uye 7 wt%, akagadzirirwawo.Zvese zvitatu zvinokonzeresa zvakaratidzwa neH2 tembiricha-yakarongwa kudzikiswa, x-ray diffraction, x-ray photoelectron spectroscopy, uye ultraviolet-inooneka spectroscopy.

Au-containing filtrate.Iyo Au-containing filtrate (Au + cC8═OOH-x) yaive in situ yakagadzirwa kubva kuAu/SiO2-catalyzed cC8═ epoxidation reaction zvinoenderana nemaitiro akagadzirwa naQian et al.(2) Isati yaita, cC8═ yakacheneswa kubvisa mugadziri-akawedzera stabilizer.Kazhinji, 50 ml ye3 M potassium hydroxide (KOH) mhinduro yakawedzerwa ku 50 ml ye cC8═ muflask.Mushure mekusanganiswa kwakakwana uye kubvongodza kwakasimba, iyo organic layer yakaunganidzwa nekuparadzaniswa.Iyi nzira yakadzokororwa neimwe 50 ml ye3 M KOH uye mamwe maviri 50 ml yeDDI mvura.Iyo cC8═ yakabva yaomeswa nesodium sulfate usiku hwose.Kuti abvise zvachose stabilizer, cC8═ yakaomeswa yakasvibiswa mubhati yemafuta inenge yakapoteredza 180 ° C, uye chikamu chakabuda pa145 ° C chakaunganidzwa.Yakanatswa cC8═ (10 ml) uye decane (1 ml) yakasanganiswa mu reactor ine 80 mg yeAu/SiO2 yambotaurwa.Iko cC8═ epoxidation reaction yakaitwa pasi pekuyerera kweokisijeni (30 ml / min) pa 100 ° C, uye kutendeuka kwakatariswa neGC.Kamwe kutendeuka kwaidiwa kwakasvika, musanganiswa wekuita wakaunganidzwa uye iyo yakasimba catalyst yakabviswa nekupisa kunopisa uchishandisa sirinji sefa.Iyo yakajairwa solubilized Au concentration iyo yakatemerwa inductively yakabatanidzwa plasma mass spectrometry yaive ingangoita 80 ng/ml, uye saizi yeAu cluster yakatemwa nefluorescence spectroscopy uye aberration-yakagadziriswa transmission electron microscopy kubva kuAu atomu kusvika ~ 0.7 nm.cC8═OOH-x yakagadzirwa zvakafanana pasina kushandisa Au/SiO2 catalyst.Zvese zviri zviviri Au + cC8═OOH-x uye cC8═OOH-x mhinduro dzine cC8═ oxidation zvigadzirwa, zvaisanganisira cyclooctene oxide, cyclooctene 3-hydroperoxide, 2-cycloocten-1-ol, 2-cycloocten-1-imwe, uye tsvaga huwandu. ye1,2-cyclooctanediol.

General maitiro.EB oxidation reactions yakaitwa murima mune matatu-mitsipa cylindrical reactor yakashongedzerwa yakanaka frit girazi disperser chubhu (Chemglass Life Sciences) uye condenser inochengetwa pa −10°C.Mukuita kwakajairwa, 7 ml yeEB, 1 ml ye decane, uye 3 ml yefiltrate (Au + cC8═OOH-x kana cC8═OOH-x) akaiswa mureactor pamwe chete neTeflon-yakavharwa magineti stirrer.Kana yakashandiswa, 32 mg ye5% Co/ZSM-5, kunze kwekunge yataurwa neimwe nzira, yakawedzerwa.Mushure mekunge maitiro ekugadzirisa akaunganidzwa, musanganiswa wekuita wakagadziriswa pasi peN2 kuyerera kwe20 min mune preheated mafuta bhati.Pane imwe nguva kutonhora kwecondenser uye bhati yemafuta yakagadziriswa, kuyerera kweO2 nguva dzose kwakapiwa pa 30 ml / min.Musanganiswa wekuita (0.1 ml) wakatorwa panguva dzakasiyana dzekuongororwa (sirinji sefa yakashandiswa kana yakasimba catalysts yakabatanidzwa), yakanyungudutswa mu0.7 ml yed-chloroform, uye yakaongororwa ne1H nuclear magnetic resonance (NMR).

Kuzivikanwa kwechigadzirwa uye quantification.Aliquots yemusanganiswa wekuita yakaderedzwa ne tetrahydrofuran uye yakaongororwa negasi chromatography-mass spectrometry (GC-MS; Agilent GC-7890A, MS-5975).Zvekuita kweEB, acetophenone uye 1-phenylethanol zvakaonekwa kuti ndizvo zvakanyanya zvigadzirwa.1H-NMR uye 13C-NMR (400 MHz Agilent DD2-MR400 system) yakashandiswa kuenderera mberi kusimbisa zvigadzirwa.1-Phenylethyl hydroperoxide, iyo isina kuonekwa neGC-MS nekuda kwekusagadzikana kwayo kwekushisa, yakaonekwa neNMR kuti ive chimwe chigadzirwa chikuru.Zvigadzirwa zvitatu zvese zvakaverengerwa ne1H-NMR vachishandisa decane seyemukati mwero (fig. S1).Kurasika kwe evaporative kwakatemwa kwakasiyana uye kwakashandiswa kugadzirisa huwandu hwechigadzirwa.Mushure mekugadzirisa kurasikirwa kweiyo evaporative, hapana kusaenzana kwekabhoni kwakaonekwa kune EB reaction.Nezve cyclooctene reaction, cyclooctene oxide, cyclooctane-1,2-diol, 2-cycloocten-1-ol, uye 2-cycloocten-1-imwe yakaverengerwa neGC.Cyclooctene 3-hydroperoxide yakanga isina kugadzikana uye yakaora muGC column uye naizvozvo haina kuonekwa.Paive negumi muzana kurasikirwa kwekabhoni pakushandurwa kuzere kunyangwe mushure mekubhadhara kurasikirwa kweiyo evaporative, iyo inogona kutsanangurwa nekugadzirwa kwezvishoma zvisingazivikanwe zvigadzirwa zvine oxidized.

Shanduko uye selectivity kukarukureta.GC kana NMR nharaunda reshiyo yemorekuru yekufarira kune yemukati mwero decane yakashandiswa kuverenga kutendeuka uye kusarudza.Kunyange zvazvo condenser yekutonhodza yakashandiswa, yainge ichiri kudiwa kutsiva kurasikirwa kwemvura nekuda kwekushisa kwakanyanya uye nguva yakareba yekuita.Evaporative kugadzirisa macurves akawanikwa kune ese EB uye cC8═ pasi pe nitrogen inoyerera uye akajairwa kureshiyo yeEB/decane kana cC8═/decane.Nekuti EB uye cC8═ zvine mapoinzi akafanana ekubikira, zvakajairwa kugadzirisa zvinhu zvakawanikwa zvese 0.0044 (yakajairwa reshiyo yakadzikira paawa).

Quantification ye hydroperoxide.Huwandu hwe hydroperoxide hwakaverengerwa nenzira mbiri dzekuti:

1) Triphenylphosphine (PPh3) titration.Ph3 (0.1 M muEB) yakashandiswa titrate isingazivikanwe hydroperoxide samples, uye poindi yekupedzisira yakaonekwa neEM Quant peroxide test strip.31P-NMR yakashandiswa kusimbisa kubviswa kwakakwana kwemhando dzehydroperoxide.

2) Iodometric titration.Sample (0.2 ml) yakasanganiswa pamwe ne 1 ml yeCHCl3 / acetic acid (v / v = 1: 2) uye 6 ml ye1 M KI mhinduro.Musanganiswa wakamutswa murima kwemaawa maviri ndokuzoiswa 0.005 M Na2S2O3 pamberi pemadonhwe mashoma emushonga we starch.Mhedziso yakasvika apo musanganiswa wakava usina ruvara.

Nzira dzose dziri mbiri dzaienderana nechomukati;zvisinei, migumisiro yavo yakasiyana ne5 kusvika ku10%.Nekuti iyo Au + cC8═OOH-x uye cC8═OOH-x yakashandiswa mupurojekiti iyi yakagadzirwa kuburikidza necC8═OOH-yakatangwa oxidation, iyo hydroperoxide concentration yaisiyana kubva batch kuenda batch asi yaigara iri mukati meiyo 0.2 kusvika 0.5 M yezvichangobva kugadzirwa. cC8═OOH-40 kusvika cC8═OOH-100 samples.Iyo hydroperoxide yakadzikira zvishoma nezvishoma nenguva yekuchengetedza.

EPR spin trap miedzo.DMPO (23 μl) yakawedzerwa kune 1 ml yesampuli kuti isvike DMPO concentration ye0.2 M, uye 20 mg yeCo/ZSM-5 yakawedzerwa kumusanganiswa wemuenzaniso muchubhu yekuedza.Musanganiswa wacho wakaitwa sonicated 1 min kuti umise catalyst, uye izvi zvakateverwa nekupisa pa 60 ° C kwe ~ 10 min.Aliquot yemusanganiswa yakaendeswa kune yakatenderedza borosilicate tubing capillary tube (1.50 mukati dhayamita × 1.80 kunze dhayamita, Wale Apparatus), iyo yakavharirwa kune imwe mugumo-iyi chubhu yakabva yaiswa muWilmad quartz X-band EPR tube ( Sigma-Aldrich).Muenzaniso wakaoma nechando nekunyudzwa kweEPR chubhu mumvura N2.Pakarepo vasati vayera EPR spectra, sampuli yakanyungudutswa.Kuenderera mberi-wave (CW) X-bhendi EPR kuyerwa kwakaitwa pakamuri tembiricha pane yakagadziridzwa Varian E-4 spectrometer uchishandisa chigunwe Dewar.

Isotopic labeling kuyedza.Deuterated EB (d10-EB) yakashandiswa mukuyedza musanganiswa we6 ml ye cC8═OOH-45, 5 ml yed10-EB, 1 ml ye decane, uye 60 mg yeCo-ZSM-5 (7%). , pa120 ° C, ne 6 ml ye cC8═OOH-45, 5 ml yeEB-d10, uye 1 ml yedodecane.Kutsiva kudzikira kweyero yekuita nekuda kwekinetic isotope athari, iyo co-oxidation yakaitwa patembiricha yepamusoro ye120 ° C.Aliquots yesampuli yakatorwa pamberi uye mushure memaawa makumi maviri nemana ekuita uye yakaongororwa ne2H-NMR uye GC-MS.

Iyo 2H-NMR spectrum (fig. S5, spectrum 2) yakaratidza mitsva mitsva yakawanda mushure mekuita, isiripo isati yaita, pa δ1.50, δ1.58, δ4.94, δ7.42 kusvika δ7.72, uye δ8.04 .Nekuda kwekuderedzwa kweJ-coupling nguva dzose uye kunzwa kwe2H-NMR, maitiro ekuparadzanisa haana kugadziriswa.Nzvimbo dzakakwirira dziri paδ8.04 uye δ7.42 kusvika δ7.72 dzakaiswa kune deuteron yerin'i inonhuhwirira yeacetophenone;mapeaks pa δ1.50 uye δ4.94 akaiswa kune methyl uye benzylic deuteron ye1-phenylethanol, zvichiteerana;uye iyo yepamusoro pa δ1.58 yakapihwa deuteron muD2O yakaumbwa kubva ku hydroperoxide decomposition.Hapana deuteron yakawanikwa yakabatana nezvigadzirwa zve cyclooctene epoxidation, uye kuumbwa kwemvura yakaderedzwa kwakaratidza kuti iyo inotungamira radical cheni inotakura mune co-oxidation reaction yaive peroxy uye alkoxy yakavakirwa.

GC-MS spectra yezvigadzirwa inoratidzwa mufig.S6.Acetophenone-d8 (m/e 128, yakazara deuterated, fig. S6A, m/e 127 uye 126) yakaonekwa.Kubva pamaitiro ekupaza, ese HD kuchinjana kwakaitika panzvimbo yemethyl.Mukuwedzera, 1-phenylethanol-d9 (m/e 131) (fig. S6B) ndiyo chete yakawanikwa deuterated zvigadzirwa.Hapana deuterium yakawanikwa mu cyclooctene oxide (fig. S6C), iyo yakanyanya kuwanda chigadzirwa kubva ku cyclooctene epoxidation.1-Phenylethanol-d9 inogona kuumbwa kubva pakuita kwe phenylethoxy radical ne cyclooctene.

Zvekuwedzera zvechinyorwa chino zvinowanikwa pa http://advances.sciencemag.org/cgi/content/full/6/5/eaax6637/DC1

Mufananidzo S5.2H-NMR isati yasvika (spectrum 1, tsvuku) uye shure (spectrum 2, girini) 24-awa co-oxidation reaction.

Mufananidzo S7.Kuenzanisa kwekutanga kushandurwa kwe4-methyl anisole yakatangwa uchishandisa Au + cC8═OOH-100, ine cC8═OOH yakabviswa.

Ichi chinyorwa chakavhurika chinogoverwa pasi pemitemo yeCreative Commons Attribution-NonCommercial rezinesi, iyo inobvumidza kushandiswa, kugovera, uye kubereka mune chero svikiro, chero mhedzisiro kushandiswa kusiri kwekutengesa bhizimusi uye kana basa rekutanga rakakodzera. quoted.

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NaAnyang Peng, Mayfair C. Kung, Robert RO Brydon, Matthew O. Ross, Linping Qian, Linda J. Broadbelt, Harold H. Kung

Mune isingabatanidzi catalytic system, vamiriri vanotorwa kubva kuAu-catalyzed cyclooctene epoxidation mhedzisiro ethylbenzene oxidation.

NaAnyang Peng, Mayfair C. Kung, Robert RO Brydon, Matthew O. Ross, Linping Qian, Linda J. Broadbelt, Harold H. Kung

Mune isingabatanidzi catalytic system, vamiriri vanotorwa kubva kuAu-catalyzed cyclooctene epoxidation mhedzisiro ethylbenzene oxidation.

© 2020 American Association yekufambira mberi kweSainzi.Kodzero dzese dzakachengetwa.AAAS ishamwari yeHINARI, AGORA, OARE, CHORUS, CLOCKSS, CrossRef uye COUNTER.Science Advances ISSN 2375-2548.