Acrylonitrile yog dab tsi?
Acrylonitrile, tseem hu ua vinyl cyanide lossis propenenitrile, yog ib qho tseem ceeb ntawm cov organic compound uas ua lub luag haujlwm tseem ceeb hauv kev tsim khoom ntawm ntau yam khoom. Nws yog dav siv nyob rau hauv kev tsim cov yas, fibers, thiab hluavtaws roj hmab. Acrylonitrile yog ib qho tsis muaj nitrile compound, txhais tau tias nws muaj cov pa roj carbon-carbon triple daim ntawv cog lus thiab ib pawg cyano (-CN) txuas rau cov pa roj carbon atom.
Keeb kwm keeb kwm
Qhov kev tshawb pom ntawm acrylonitrile tuaj yeem taug qab mus rau lub xyoo pua puv 19. Tus German chemist Matthias Ungewitter thawj zaug nws tau tsim nyob rau hauv 1893 los ntawm cua sov allyl cyanide. Txawm li cas los xij, nws tsis yog txog thaum nruab nrab -20th xyoo pua uas muaj kev lag luam-scale tsim acrylonitrile pib.
Synthesis ntawm Acrylonitrile
Acrylonitrile feem ntau yog tsim los ntawm cov txheej txheem hu ua ammoxidation, uas cuam tshuam cov tshuaj tiv thaiv ntawm propylene, ammonia, thiab huab cua dhau lub catalyst. Cov tshuaj tiv thaiv no tshwm sim hauv ntau cov txheej txheem thiab yuav tsum tau ceev faj tswj qhov kub, siab, thiab lwm yam.
Thawj kauj ruam suav nrog dehydrogenation ntawm propylene los ua propylene oxide, uas yog tom qab ntawd ntxiv oxidized rau acrolein. Acrolein, nyob rau hauv lub xub ntiag ntawm ammonia, undergoes ib tug condensation cov tshuaj tiv thaiv rau yield acrylonitrile. Cov txheej txheem no yog ua nyob rau ntawm qhov kub ntawm 350 txog 500 degrees Celsius, nrog rau qhov kub ntawm 1 mus rau 5 cua.
Acrylonitrile kuj tseem tuaj yeem tsim los ntawm catalytic kua-theem ammoxidation ntawm propylene. Nyob rau hauv txoj kev no, propylene, ammonia, thiab cua yog reacted nyob rau hauv ib tug ua kua theem siv ib tug haum catalyst. Cov txheej txheem ua kua-theem muaj qee qhov zoo, xws li txhim kho kev xaiv thiab tswj tau yooj yim ntawm cov tshuaj tiv thaiv tsis zoo.
Cov khoom siv raw
Cov khoom siv tseem ceeb rau kev tsim cov acrylonitrile yog propylene, cov khoom siv los ntawm cov roj av refining thiab natural gas processing. Propylene yog cov roj uas tsis muaj xim, flammable gas uas tau muab los ntawm kev tawg ntawm hydrocarbon feedstocks. Nws yog dav siv thiab ua qhov chaw pib rau kev tsim khoom ntawm ntau yam khoom siv tshuaj tseem ceeb.
Ammonia yog ib qho tseem ceeb raw khoom siv nyob rau hauv lub synthesis ntawm acrylonitrile. Ammonia yog tsim los ntawm cov txheej txheem Haber-Bosch, uas koom nrog cov tshuaj tiv thaiv ntawm nitrogen thiab hydrogen ntawm qhov kub thiab txias. Ammonia yog ib qho tseem ceeb hauv kev lag luam ntau yam, suav nrog kev ua liaj ua teb, kev tsim tshuaj, thiab tshuaj.
Cua, tshwj xeeb tshaj yog oxygen, yog qhov tseem ceeb thib peb raw khoom xav tau rau kev tsim cov acrylonitrile. Nws ua haujlwm ua oxidant hauv cov txheej txheem ammoxidation, tso cai rau kev hloov pauv ntawm propylene rau acrylonitrile los ntawm cov kauj ruam nruab nrab.
Catalysts
Catalysts ua lub luag haujlwm tseem ceeb hauv kev tsim cov acrylonitrile. Lawv pab txhawb cov tshuaj tiv thaiv ntawm propylene, ammonia, thiab huab cua, ua kom cov tshuaj tiv thaiv tsis tau noj lawv tus kheej. Qhov feem ntau siv catalyst rau ammoxidation ntawm propylene rau acrylonitrile yog ua raws li cov hlau oxide sib xyaw.
Cov catalyst feem ntau muaj oxides ntawm bismuth, molybdenum, thiab phosphorus, nrog rau ntxiv txhawb xws li potassium los yog cesium. Kev xaiv ntawm catalyst muaj pes tsawg leeg cuam tshuam rau kev xaiv thiab kev ua haujlwm ntawm cov tshuaj tiv thaiv. Kev txhim kho thiab kev txhim kho catalyst tau txuas ntxiv los txhim kho cov txiaj ntsig thiab txo qhov cuam tshuam ib puag ncig ntawm acrylonitrile synthesis.
Kev siv ntawm Acrylonitrile
Acrylonitrile tau siv dav hauv ntau qhov kev lag luam vim nws cov khoom tshwj xeeb. Nws daim ntawv thov tseem ceeb tshaj plaws yog nyob rau hauv kev tsim cov acrylic fibers, feem ntau hu ua acrylic wool. Acrylic fibers yog lub teeb yuag, mos, thiab muaj cov thermal thiab tshuaj lom neeg zoo. Lawv tau siv dav hauv kev lag luam textile rau kev tsim cov khaub ncaws, ntaub pua plag, upholstery, thiab lwm yam khoom siv ntaub.
Lwm qhov tseem ceeb ntawm acrylonitrile yog nyob rau hauv kev tsim cov acrylonitrile-butadiene-styrene (ABS) plastics. ABS yog ntau yam thermoplastic uas muaj kev cuam tshuam zoo heev, kev ruaj ntseg zoo, thiab qhov kub thiab txias. Nws pom cov ntawv thov hauv kev lag luam xws li tsheb, hluav taws xob, khoom siv, thiab cov khoom siv.
Acrylonitrile kuj yog ib qho tseem ceeb hauv kev tsim cov roj hmab hluavtaws, tshwj xeeb yog cov roj hmab nitrile lossis NBR. Nitrile roj hmab nthuav tawm cov roj zoo dua thiab hnyav hnyav, ua rau nws tsim nyog rau ntau hom kev lag luam, suav nrog gaskets, hoses, seals, thiab hnab looj tes.
Tsis tas li ntawd, acrylonitrile yog siv rau hauv kev sib txuas ntawm ntau yam tshuaj tshwj xeeb, suav nrog adiponitrile, ib qho tseem ceeb hauv kev tsim cov nylon-6,6. Lwm cov tshuaj tshwj xeeb tau muab los ntawm acrylonitrile suav nrog acrylamide, acrylic acid, thiab methacrylonitrile, uas pom cov ntawv thov hauv ntau yam lag luam xws li tshuaj, tshuaj nplaum, thiab txheej txheej.
Kev saib xyuas kev nyab xeeb thiab ib puag ncig
Acrylonitrile yog cais raws li tshuaj lom neeg vim nws toxicity thiab flammability. Kev cuam tshuam rau cov kua acrylonitrile ntau ntau los yog kua tuaj yeem ua rau muaj kev phom sij rau kev noj qab haus huv, nrog rau cov tawv nqaij thiab qhov muag khaus, ua pa nyuaj, thiab hauv qhov xwm txheej hnyav, nws tuaj yeem ua rau mob carcinogenic.
Hais txog ib puag ncig, acrylonitrile yog qhov pheej hmoo heev thiab tuaj yeem ua rau cov av thiab dej muaj kuab paug yog tso tawm yam tsis muaj kev kho kom raug. Kev siv zog tau tsim los txhim kho cov txheej txheem eco-phooj ywg ntau dua rau kev tsim cov acrylonitrile thiab txo nws cov kev cuam tshuam ib puag ncig los ntawm kev tswj cov khib nyiab thiab kev tswj cov pa phem.
Xaus
Hauv kev xaus, acrylonitrile yog ib qho tseem ceeb ntawm cov organic compound feem ntau muab los ntawm propylene los ntawm ntau cov txheej txheem ammoxidation. Lub synthesis ntawm acrylonitrile koom nrog kev ceev faj cov tshuaj tiv thaiv ntawm propylene, ammonia, thiab huab cua dhau ntawm qhov tsim nyog catalyst. Acrylonitrile pom cov ntawv thov hauv kev tsim cov acrylic fibers, ABS yas, hluavtaws roj hmab, thiab cov tshuaj tshwj xeeb. Thaum acrylonitrile muaj ntau yam txiaj ntsig, kev nyab xeeb thiab ib puag ncig kev xav yuav tsum tau coj mus rau hauv tus account thaum lub sijhawm tsim khoom, tuav, thiab pov tseg kom muaj kev noj qab haus huv ntawm tib neeg thiab ib puag ncig.
