Vinyl acetate (VAc), yomwe imadziwikanso kuti vinyl acetate kapena vinyl acetate, ndi madzi osawoneka bwino omwe amatha kutentha komanso kupanikizika, okhala ndi mamolekyu a C4H6O2 ndi molekyulu yolemera 86.9.VAc, monga imodzi mwazinthu zomwe zimagwiritsidwa ntchito kwambiri m'mafakitale padziko lonse lapansi, imatha kupanga zotumphukira monga polyvinyl acetate resin (PVAc), polyvinyl alcohol (PVA), ndi polyacrylonitrile (PAN) kudzera pakupanga polymerization kapena copolymerization ndi ma monomers ena.Zochokera ku izi zimagwiritsidwa ntchito kwambiri pomanga, nsalu, makina, mankhwala, ndi kukonza nthaka.Chifukwa chakukula kwachangu kwa mafakitale omaliza m'zaka zaposachedwa, kupanga vinyl acetate kwawonetsa kuchulukirachulukira chaka ndi chaka, ndikupanga chiwopsezo cha vinyl acetate kufika ku 1970kt mu 2018. Pakalipano, chifukwa cha mphamvu ya zipangizo ndi Njira, njira zopangira vinyl acetate makamaka zimaphatikizapo njira ya acetylene ndi njira ya ethylene.
1, Njira ya Acetylene
Mu 1912, F. Klatte, wa ku Canada, anapeza koyamba vinyl acetate pogwiritsa ntchito acetylene ndi acetic acid mopitirira muyeso wa mumlengalenga, pa kutentha kuyambira 60 mpaka 100 ℃, ndi kugwiritsa ntchito mchere wa mercury monga chothandizira.Mu 1921, Germany CEI Company idapanga ukadaulo wopangira mpweya wa vinyl acetate kuchokera ku acetylene ndi acetic acid.Kuyambira pamenepo, ofufuza ochokera kumayiko osiyanasiyana apitiliza kuwongolera njira ndi mikhalidwe ya kaphatikizidwe ka vinyl acetate kuchokera ku acetylene.Mu 1928, Hoechst Company yaku Germany idakhazikitsa gawo lopangira 12 kt/acetate vinyl acetate, pozindikira kupanga kwakukulu kwamakampani opanga vinyl acetate.Equation yopanga vinyl acetate ndi njira ya acetylene ndi motere:
Ndemanga yayikulu:

Zotsatira zake:

Njira ya Acetylene imagawidwa mu njira yamadzimadzi ndi njira ya gasi.
The reactant gawo boma la acetylene madzi gawo njira ndi madzi, ndi riyakitala ndi anachita thanki ndi oyambitsa chipangizo.Chifukwa cha zofooka za njira yamadzimadzi monga kusankhidwa kochepa ndi zinthu zambiri zowonongeka, njirayi yasinthidwa ndi njira ya gawo la acetylene pakalipano.
Malinga ndi magwero osiyanasiyana akukonzekera gasi wa acetylene, njira ya gasi ya acetylene imatha kugawidwa mu njira ya gasi ya acetylene Borden ndi njira ya carbide acetylene Wacker.
Njira ya Borden imagwiritsa ntchito acetic acid ngati adsorbent, yomwe imathandizira kwambiri kugwiritsa ntchito acetylene.Komabe, njira imeneyi ndi yovuta mwaukadaulo ndipo imafuna ndalama zambiri, motero njira iyi imakhala yopindulitsa m'malo omwe ali ndi gasi wochuluka.
Njira ya Wacker imagwiritsa ntchito acetylene ndi asidi acetic opangidwa kuchokera ku calcium carbide ngati zopangira, pogwiritsa ntchito chothandizira chokhala ndi kaboni wa activated monga chonyamulira ndi zinc acetate monga gawo logwira ntchito, kupanga VAc pansi pa mphamvu ya mlengalenga ndi kutentha kwa 170 ~ 230 ℃.Ukadaulo wanjira ndi wosavuta komanso uli ndi ndalama zochepa zopangira, koma pali zofooka monga kutayika kosavuta kwa zida zogwira ntchito, kusakhazikika bwino, kugwiritsa ntchito mphamvu zambiri, komanso kuipitsa kwakukulu.
2, Ethylene ndondomeko
Ethylene, oxygen, ndi glacial acetic acid ndi zida zitatu zomwe zimagwiritsidwa ntchito popanga ethylene synthesis ya vinyl acetate process.Waukulu yogwira chigawo chimodzi cha chothandizira ndi amangoona gulu lachisanu ndi chitatu wolemekezeka zitsulo chinthu, amene anachita pa ena anachita kutentha ndi kuthamanga.Pambuyo pakukonza kotsatira, chinthu chomwe mukufuna vinyl acetate chimapezedwa.Ma reaction equation ndi awa:
Ndemanga yayikulu:

Zotsatira zake:

Njira ya gawo la ethylene vapor phase idapangidwa koyamba ndi Bayer Corporation ndipo idayikidwa m'mafakitale kuti apange vinyl acetate mu 1968. Mizere yopangira idakhazikitsidwa ku Hearst ndi Bayer Corporation ku Germany ndi National Distillers Corporation ku United States, motsatana.Makamaka palladium kapena golide wodzaza ndi asidi kusamva zothandizira, monga mikanda silika gel osakaniza ndi utali wozungulira 4-5mm, ndi Kuwonjezera enaake potaziyamu acetate, amene angathe kusintha ntchito ndi selectivity wa chothandizira.Njira yopangira vinyl acetate pogwiritsa ntchito ethylene nthunzi gawo la USI njira ndi yofanana ndi njira ya Bayer, ndipo imagawidwa m'magawo awiri: kaphatikizidwe ndi distillation.Njira ya USI inapeza ntchito ya mafakitale mu 1969. Zomwe zimagwiritsidwa ntchito pa chothandizira ndizo makamaka palladium ndi platinamu, ndipo wothandizira ndi potaziyamu acetate, yomwe imathandizidwa pa chonyamulira cha alumina.Zomwe zimachitika zimakhala zofatsa ndipo chothandizira chimakhala ndi moyo wautali wautumiki, koma zokolola za nthawi ndizochepa.Poyerekeza ndi njira ya acetylene, njira ya gawo la nthunzi ya ethylene yakula kwambiri mu teknoloji, ndipo zowonjezera zomwe zimagwiritsidwa ntchito mu njira ya ethylene zakhala zikuyenda bwino muzochita ndi kusankha.Komabe, ma reaction kinetics ndi deactivation mechanism ikufunikabe kufufuzidwa.
Kupanga kwa vinyl acetate pogwiritsa ntchito njira ya ethylene kumagwiritsira ntchito tubular fixed bed reactor yodzazidwa ndi chothandizira.Mpweya wopatsa chakudya umalowa mu riyakitala kuchokera pamwamba, ndipo ukalumikizana ndi bedi lothandizira, zimachitika kuti apange chandamale cha vinyl acetate ndi kanyumba kakang'ono ka carbon dioxide.Chifukwa exothermic chikhalidwe cha zimene, mbamuikha madzi umalowetsedwa mu chipolopolo mbali ya riyakitala kuchotsa anachita kutentha ntchito vaporization madzi.
Poyerekeza ndi njira ya acetylene, njira ya ethylene imakhala ndi mawonekedwe a chipangizo chophatikizika, kutulutsa kwakukulu, kugwiritsa ntchito mphamvu zochepa, komanso kuipitsa pang'ono, ndipo mtengo wake wamankhwala ndi wotsika kuposa njira ya acetylene.Ubwino wa mankhwalawo ndiwopambana, ndipo kuwonongeka kwa dzimbiri sikovuta.Choncho, ethylene njira pang'onopang'ono m'malo acetylene pambuyo 1970s.Malinga ndi ziwerengero zosakwanira, pafupifupi 70% ya VAc yopangidwa ndi njira ya ethylene padziko lapansi yakhala njira yayikulu yopangira VAc.
Pakadali pano, ukadaulo wapamwamba kwambiri wopanga VAc padziko lapansi ndi BP's Leap Process ndi Celanese's Vantage process.Poyerekeza ndi chikhalidwe chokhazikika bedi gasi gawo ethylene ndondomeko, awiriwa ndondomeko matekinoloje kwambiri bwino riyakitala ndi chothandizira pachimake cha unit, kuwongolera chuma ndi chitetezo cha ntchito unit.
Celanese yapanga njira yatsopano yokhazikika ya bedi la Vantage kuti athetse mavuto omwe amagawanitsa bedi la bedi ndi ethylene yotsika kutembenuka kwa njira imodzi muzitsulo zokhazikika.The riyakitala ntchito mu ndondomekoyi akadali bedi lokhazikika, koma kusintha kwakukulu kwapangidwa ku dongosolo chothandizira, ndi ethylene kuchira zipangizo zawonjezedwa mu mpweya mchira, kugonjetsa zofooka za chikhalidwe chokhazikika njira bedi.Zokolola za vinyl acetate ndizokwera kwambiri kuposa zida zofanana.Njira yothandizirayi imagwiritsa ntchito platinamu monga chigawo chachikulu chogwira ntchito, gel silica gel monga chotengera chothandizira, sodium citrate monga kuchepetsa, ndi zitsulo zina zothandizira monga lanthanide zachilendo zapadziko lapansi monga praseodymium ndi neodymium.Poyerekeza ndi zolimbikitsa zachikhalidwe, kusankha, zochita, ndi zokolola za nthawi ya mlengalenga za chothandizira zimawongoleredwa.
BP Amoco yapanga gawo la gasi la bedi la ethylene, lomwe limadziwikanso kuti Leap Process process, ndipo lamanga bedi la 250 kt / fluidized bed ku Hull, England.Kugwiritsa ntchito njirayi kuti mupange vinyl acetate kungachepetse mtengo wopangira ndi 30%, ndipo nthawi yokolola ya chothandizira (1858-2744 g / (L · h-1)) ndi yapamwamba kwambiri kuposa ndondomeko ya bedi lokhazikika (700). -1200 g/(L · h-1)).
Njira ya LeapProcess imagwiritsa ntchito choyatsira bedi chamadzimadzi kwa nthawi yoyamba, chomwe chili ndi zabwino zotsatirazi poyerekeza ndi choyatsira bedi chokhazikika:
1) Mu riyakitala ya bedi yamadzimadzi, chothandiziracho chimakhala chosakanikirana mosalekeza, motero chimathandizira kufalikira kwa yunifolomu kwa wolimbikitsa ndikuwonetsetsa kuti ndende ya yunifolomu ya wolimbikitsira mu riyakitala.
2) The fluidized bedi riyakitala akhoza mosalekeza m'malo chothandizira deactivated ndi chothandizira mwatsopano pansi ntchito zikhalidwe.
3) The fluidized bedi anachita kutentha ndi nthawi zonse, kuchepetsa chothandizira deactivation chifukwa kutenthedwa m'deralo, potero kuwonjezera moyo utumiki wa chothandizira.
4) Njira yochotsera kutentha yomwe imagwiritsidwa ntchito pa bedi la fluidized riyakitala imathandizira kapangidwe ka riyakitala ndikuchepetsa kuchuluka kwake.Mwa kuyankhula kwina, kapangidwe ka riyakitala kamodzi chitha kugwiritsidwa ntchito poyika mankhwala akuluakulu, kupititsa patsogolo mphamvu ya chipangizocho.