Cia peb tham txog yuav ua li cas toluene yog nitrated. Ib tug loj npaum li cas ntawm semi-tiav khoom siv nyob rau hauv lub tsim ntawm explosives, tshuaj yog tau los ntawm xws li kev sib cuam tshuam.
Qhov tseem ceeb ntawm nitration
Benzene derivatives nyob rau hauv daim ntawv ntawm aromatic nitro tebchaw yog tsim nyob rau hauv lub niaj hnub tshuaj kev lag luam. Nitrobenzene yog ib qho khoom nruab nrab hauv aniline, perfumery, tshuaj ntau lawm. Nws yog ib qho hnyav heev rau ntau cov organic tebchaw, suav nrog cellulose nitrite, tsim cov gelatinous loj nrog nws. Hauv kev lag luam roj av, nws yog siv los ua lub tshuab nqus tsev ntxhua khaub ncaws. Nitration ntawm toluene muab benzidine, aniline, aminosalicylic acid, phenylenediamine.
Nitration yam ntxwv
Nitration yog tus cwj pwm los ntawm kev qhia ntawm NO2 pawg rau hauv cov molecule ntawm cov organic compound. Nyob ntawm seb cov khoom pib, cov txheej txheem no tau ua raws li lub hauv paus radical, nucleophilic, electrophilic mechanism. Nitronium cations, ions thiab NO2 radicals ua raws li cov khoom nquag. Cov tshuaj tiv thaiv nitration ntawm toluene hais txog kev hloov pauv. Rau lwm cov organic tshuajKev hloov pauv nitration tuaj yeem ua tau, nrog rau kev ntxiv ntawm ob daim ntawv cog lus.
Nitration ntawm toluene nyob rau hauv ib qho aromatic hydrocarbon molecule yog nqa tawm siv nitrating sib tov (sulfuric thiab nitric acids). Cov khoom catalytic tau nthuav tawm los ntawm sulfuric acid, uas ua raws li cov dej tshem tawm hauv cov txheej txheem no.
txheej txheem sib npaug
Nitration ntawm toluene cuam tshuam txog kev hloov ntawm ib lub atom hydrogen nrog ib pawg nitro. Daim duab txheej txheem zoo li cas?
Txhawm rau piav qhia txog nitration ntawm toluene, qhov sib npaug ntawm cov tshuaj tiv thaiv tuaj yeem sawv cev raws li hauv qab no:
ArH + HONO2 +=Ar-NO2 + H2 O
Nws tso cai rau peb txiav txim tsuas yog kev sib tham dav dav, tab sis tsis qhia tag nrho cov yam ntxwv ntawm cov txheej txheem no. Qhov tshwm sim tiag tiag yog cov tshuaj tiv thaiv ntawm cov tshuaj tsw qab hydrocarbons thiab cov khoom siv nitric acid.
Muab hais tias muaj cov dej molecules hauv cov khoom, qhov no ua rau txo qis ntawm nitric acid, yog li nitration ntawm toluene qeeb. Txhawm rau zam qhov teeb meem no, cov txheej txheem no yog ua los ntawm qhov kub thiab txias, siv nitric acid ntau dhau.
Ntxiv rau sulfuric acid, acetic anhydride, polyphosphoric acids, boron trifluoride yog siv los ua cov dej tshem tawm. Lawv ua kom muaj peev xwm txo qis kev noj cov nitric acid, nce kev ua haujlwm ntawm kev sib cuam tshuam.
Nuances of the process
Nitration ntawm toluene tau piav qhia nyob rau thaum xaus ntawm lub xyoo pua puv 19 los ntawm V. Markovnikov. Nws tau tswj kom tsim kom muaj kev sib txuas ntawm qhov muaj cov concentrated sulfuric acid nyob rau hauv cov tshuaj tiv thaiv sib tov thiab tus nqi ntawm cov txheej txheem. Nyob rau hauv niaj hnub zus tau tej cov nitrotoluene, anhydrous nitric acid yog siv, noj nyob rau hauv ib co dhau.
Ntxiv rau, sulfonation thiab nitration ntawm toluene yog txuam nrog kev siv cov dej tshem tawm ntawm boron fluoride. Nws qhov kev taw qhia rau hauv cov txheej txheem tshuaj tiv thaiv ua rau nws tuaj yeem txo tus nqi ntawm cov khoom tshwm sim, uas ua rau muaj nitration ntawm toluene. Qhov sib npaug ntawm cov txheej txheem tam sim no hauv daim ntawv dav dav yog nthuav tawm hauv qab no:
ArH + HNO3 + BF3=Ar-NO2 + BF3 H2 O
Tom qab ua tiav ntawm kev sib cuam tshuam, dej tau qhia, vim tias boron fluoride monohydrate tsim cov dihydrate. Nws yog distilled tawm hauv lub tshuab nqus tsev, ces calcium fluoride ntxiv, rov qab cov compound rau nws daim ntawv qub.
Nitration specifications
Muaj qee yam ntawm cov txheej txheem no ntsig txog kev xaiv cov tshuaj reagents, cov tshuaj tiv thaiv substrate. Xav txog qee qhov ntawm lawv cov kev xaiv hauv kev nthuav dav ntxiv:
- 60-65% nitric acid tov nrog 96% sulfuric acid;
- sib tov ntawm 98% nitric acid thiab concentrated sulfuric acid yog haum rau me ntsis reactive organics;
- poov tshuaj lossis ammonium nitrate nrog concentrated sulfuric acid yog ib qho kev xaiv zoo tshaj plaws rau kev tsim cov polymeric nitro compounds.
Nitration kinetics
Aromatic hydrocarbons cuam tshuam nrog kev sib xyaw ntawm sulfuric thiabnitric acids yog nitrated los ntawm ionic mechanism. V. Markovnikov tau tswj hwm tus yam ntxwv ntawm qhov kev sib cuam tshuam no. Cov txheej txheem pib ua ntau theem. Ua ntej, nitrosulfuric acid yog tsim, uas undergoes dissociation nyob rau hauv ib tug aqueous tov. Nitronium ions react nrog toluene, tsim nitrotoluene ua ib yam khoom. Thaum cov dej molecules ntxiv rau qhov sib tov, cov txheej txheem qeeb qeeb.
Nyob rau hauv cov kuab tshuaj nrog cov organic - nitromethane, acetonitrile, sulfolane - tsim cov cation tso cai rau koj kom nce tus nqi ntawm nitration.
Cov txiaj ntsig nitronium cation txuas nrog rau lub hauv paus ntawm aromatic toluene, thiab ib qho kev sib xyaw nruab nrab yog tsim. Tom ntej no, ib tug proton yog detached, ua rau tsim ntawm nitrotoluene.
Rau cov lus piav qhia ntxaws ntxaws ntawm cov txheej txheem txuas ntxiv, peb tuaj yeem xav txog qhov tsim ntawm "sigma" thiab "pi" complexes. Kev tsim ntawm "sigma" complex yog qhov txwv theem ntawm kev sib cuam tshuam. Cov tshuaj tiv thaiv tus nqi yuav ncaj qha rau tus nqi ntxiv ntawm nitronium cation rau carbon atom nyob rau hauv lub nucleus ntawm aromatic compound. Kev tshem tawm ntawm proton los ntawm toluene yog yuav luag tam sim.
Tsuas yog qee qhov xwm txheej tuaj yeem muaj teeb meem hloov pauv cuam tshuam nrog cov txiaj ntsig tseem ceeb ntawm kinetic isotope. Qhov no yog vim lub acceleration ntawm tus txheej txheem rov qab nyob rau hauv lub xub ntiag ntawm ntau yam obstacles.
Thaum xaiv cov concentrated sulfuric acid ua cov catalyst thiab dewatering tus neeg sawv cev, kev hloov pauv hauv qhov sib npaug ntawm cov txheej txheem ntawm kev tsim cov khoom siv tshuaj tiv thaiv yog pom.
Zoo kawg
Thaum toluene yog nitrated, nitrotoluene tsim, uas yog ib qho khoom muaj txiaj ntsig ntawm kev lag luam tshuaj. Nws yog cov khoom no uas yog cov khoom tawg, yog li nws yog qhov xav tau hauv blasting. Ntawm cov teeb meem ib puag ncig uas cuam tshuam nrog nws cov khoom lag luam, peb nco ntsoov siv ntau npaum li cas ntawm cov concentrated sulfuric acid.
Yuav daws qhov teeb meem no, cov kws kho mob tab tom nrhiav txoj hauv kev los txo cov sulfuric acid pov tseg uas tsim los ntawm cov txheej txheem nitration. Piv txwv li, cov txheej txheem yog nqa tawm ntawm qhov kub thiab txias, yooj yim regenerated media yog siv. Sulfuric acid muaj zog oxidizing zog, uas cuam tshuam tsis zoo rau corrosion ntawm hlau thiab ua rau muaj kev phom sij ntau ntxiv rau cov kab mob nyob. Yog tias tag nrho cov qauv kev nyab xeeb raug soj ntsuam, cov teeb meem no tuaj yeem daws tau thiab cov tshuaj nitro zoo tuaj yeem tau.
