I-Vinyl acetate (VAc), eyaziwa ngokuba yi-vinyl acetate okanye i-vinyl acetate, i-liquid engenambala ecacileyo kwiqondo lokushisa eliqhelekileyo kunye noxinzelelo, kunye ne-molecular formula ye-C4H6O2 kunye ne-molecular weight ye-86.9.I-VAc, njengenye yezona zinto zisetyenziswa kakhulu kwimizi-mveliso yendalo ekrwada kwihlabathi, inokuvelisa izinto eziphuma kwi-polyvinyl acetate resin (PVAc), i-polyvinyl alcohol (PVA), kunye ne-polyacrylonitrile (PAN) ngokuzenza i-polymerization okanye i-copolymerization nezinye ii-monomers.Ezi zixhobo zisetyenziswa ngokubanzi kulwakhiwo, kwilaphu, koomatshini, kumayeza, nasekuphuculeni umhlaba.Ngenxa yophuhliso olukhawulezayo lweshishini le-terminal kwiminyaka yakutshanje, ukuveliswa kwe-vinyl acetate kubonise ukuthambekela kokunyuka konyaka, kunye nemveliso epheleleyo ye-vinyl acetate ifikelela kwi-1970kt ngo-2018. Okwangoku, ngenxa yempembelelo yezinto eziluhlaza kunye iinkqubo, iindlela zokuvelisa i-vinyl acetate ikakhulu ziquka indlela ye-acetylene kunye nendlela ye-ethylene.
1. Inkqubo yeAcetylene
Ngo-1912, uF. Klatte, waseKhanada, waqala ukufumanisa i-vinyl acetate esebenzisa i-acetylene engaphezulu kunye ne-acetic acid phantsi koxinzelelo lwe-atmospheric, kumaqondo obushushu aqala kwi-60 ukuya kwi-100 ℃, kunye nokusebenzisa i-mercury salts njengezinto zokuvuselela.Ngowe-1921, iNkampani ye-CEI yaseJamani yavelisa itekhnoloji yokwenziwa kwesigaba somphunga se-vinyl acetate ukusuka kwi-acetylene kunye ne-acetic acid.Ukusukela ngoko, abaphandi abavela kumazwe ahlukeneyo baye baqhubeka bephucula inkqubo kunye neemeko zokwenziwa kwe-vinyl acetate evela kwi-acetylene.Ngomnyaka we-1928, iNkampani ye-Hoechst yaseJamani yaseka iyunithi yemveliso ye-vinyl acetate eyi-12 / vinyl, iqonda imveliso enkulu ye-vinyl acetate.I-equation yokuvelisa i-vinyl acetate ngendlela ye-acetylene ilandelayo:
Eyona mpendulo:

Imiphumela:

Indlela ye-acetylene yahlulwe kwindlela yesigaba solwelo kunye nendlela yesigaba segesi.
Imo yesigaba esisabelayo sendlela yesigaba solwelo lwe-acetylene lulwelo, kwaye i-reactor yitanki yokusabela enesixhobo esishukumisayo.Ngenxa yokungaphumeleli kwendlela yesigaba se-liquid ezifana nokukhetha okuphantsi kunye neemveliso ezininzi, le ndlela ithathelwe indawo yindlela yesigaba segesi ye-acetylene okwangoku.
Ngokwemithombo eyahlukeneyo yokulungiswa kwegesi ye-acetylene, indlela yesigaba segesi ye-acetylene inokwahlulwa ibe yigesi yendalo ye-acetylene indlela ye-Borden kunye ne-carbide acetylene Wacker indlela.
Inkqubo yaseBorden isebenzisa i-acetic acid njenge-adsorbent, ephucula kakhulu izinga lokusetyenziswa kwe-acetylene.Nangona kunjalo, le ndlela yenkqubo inzima ngokobugcisa kwaye ifuna iindleko eziphezulu, ngoko ke le ndlela ithatha inzuzo kwiindawo ezityebileyo kwimithombo yegesi yendalo.
Inkqubo ye-Wacker isebenzisa i-acetylene kunye ne-acetic acid eveliswa kwi-calcium carbide njengezinto eziluhlaza, isebenzisa i-catalyst enekhabhoni esebenzayo njenge-carrier kunye ne-acetate ye-zinc njengenxalenye esebenzayo, ukudibanisa i-VAc phantsi koxinzelelo lwe-atmospheric kunye nobushushu bokusabela kwe-170 ~ 230 ℃.Itekhnoloji yenkqubo ilula ngokwentelekiso kwaye ineendleko eziphantsi zemveliso, kodwa kukho iziphene ezinjengokulahleka ngokulula kwamacandelo e-catalyst asebenzayo, uzinzo olulambathayo, ukusetyenziswa kwamandla aphezulu, kunye nongcoliseko olukhulu.
2. Inkqubo ye-ethylene
I-ethylene, ioksijini, kunye ne-glacial acetic acid zizinto ezintathu ezisetyenziswa kwi-ethylene synthesis ye-vinyl acetate process.Elona candelo lisebenzayo le-catalyst ngokuqhelekileyo liqela lesibhozo lentsimbi ehloniphekileyo, ephendulwa kwiqondo elithile lobushushu kunye noxinzelelo.Emva kokucubungula okulandelayo, imveliso ejoliswe kuyo i-vinyl acetate ifunyenwe ekugqibeleni.I-reaction equation imi ngolu hlobo lulandelayo:
Eyona mpendulo:

Imiphumela:

Inkqubo yesigaba somphunga we-ethylene yaphuhliswa okokuqala yi-Bayer Corporation kwaye yafakwa kwimveliso yemveliso ye-vinyl acetate ngo-1968.Ikakhulu i-palladium okanye igolide elayishwe kwiinkxaso ezichasene ne-asidi, njenge-silica gel ubuhlalu kunye ne-radius ye-4-5mm, kunye nokongezwa kwenani elithile le-acetate ye-potassium, enokuphucula umsebenzi kunye nokukhetha kwe-catalyst.Inkqubo yokwenziwa kwe-vinyl acetate usebenzisa i-ethylene vapor isigaba indlela ye-USI ifana nendlela ye-Bayer, kwaye ihlukaniswe yaba ngamacandelo amabini: i-synthesis kunye ne-distillation.Inkqubo ye-USI iphumelele kwi-industrial application kwi-1969. Amacandelo asebenzayo e-catalyst ikakhulu i-palladium kunye ne-platinum, kwaye i-agent encedisayo yi-acetate ye-potassium, exhaswa kwi-carrier ye-alumina.Iimeko zokusabela zincinci kwaye i-catalyst inobomi obude benkonzo, kodwa isivuno sexesha lesithuba siphantsi.Xa kuthelekiswa nendlela ye-acetylene, indlela yesigaba somphunga we-ethylene iphuculwe kakhulu kwithekhnoloji, kwaye i-catalysts esetyenziswe kwindlela ye-ethylene iye yaphucula ngokuqhubekayo kumsebenzi kunye nokukhetha.Nangona kunjalo, i-reaction kinetics kunye ne-deactivation mechanism zisafuna ukuphononongwa.
Ukuveliswa kwe-vinyl acetate usebenzisa indlela ye-ethylene isebenzisa i-reactor ye-bed fixed tubular egcwele i-catalyst.Irhasi yokutya ingena kwi-reactor ukusuka phezulu, kwaye xa iqhagamshelana nebhedi ye-catalyst, ii-catalytic reactions zenzeka ukuvelisa imveliso ekujoliswe kuyo i-vinyl acetate kunye nenani elincinci lemveliso ye-carbon dioxide.Ngenxa yendalo exothermic yokusabela, amanzi acinezelekileyo angeniswa kwicala leqokobhe le-reactor ukususa ubushushu bokusabela ngokusebenzisa umphunga wamanzi.
Xa kuthelekiswa nendlela ye-acetylene, indlela ye-ethylene ineempawu zesakhiwo se-compact device, imveliso enkulu, ukusetyenziswa kwamandla aphantsi, kunye nokungcola okuncinci, kunye neendleko zemveliso ziphantsi kunendlela ye-acetylene.Umgangatho wemveliso uphezulu, kwaye imeko ye-corrosion ayinzima kakhulu.Ngoko ke, indlela ye-ethylene ngokuthe ngcembe yatshintsha indlela ye-acetylene emva kweminyaka yee-1970.Ngokwezibalo ezingaphelelanga, malunga ne-70% ye-VAc eveliswe ngendlela ye-ethylene kwihlabathi iye yaba yeyona ndlela yokuvelisa i-VAc.
Okwangoku, obona buchwepheshe buphambili bemveliso yeVAc ehlabathini yi-BP's Leap Process kunye neCelanese's Vantage Process.Xa kuthelekiswa nenkqubo yesigaba se-ethylene yegesi esisigxina, ezi teknoloji zimbini ziyiphucule kakhulu i-reactor kunye ne-catalyst kumbindi weyunithi, ukuphucula uqoqosho kunye nokhuseleko lomsebenzi weyunithi.
I-Celanese iphuhlise inkqubo entsha ye-Vantage yebhedi esisigxina ukujongana neengxaki zokusasazwa kwebhedi ye-catalyst engalinganiyo kunye ne-ethylene ephantsi yokuguqulwa kwendlela enye kwi-reactors bed fixed.I-reactor esetyenziswe kule nkqubo isengumbhede osisigxina, kodwa uphuculo oluphawulekayo lwenziwe kwinkqubo ye-catalyst, kwaye izixhobo zokubuyisela i-ethylene zongezwa kwi-gas yomsila, ukoyisa ukusilela kweenkqubo zokulala ezisisigxina zendabuko.Imveliso ye-vinyl acetate iphezulu kakhulu kunezixhobo ezifanayo.Inkqubo ye-catalyst isebenzisa i-platinum njengeyona nto isebenzayo, i-silica gel njenge-catalyst carrier, i-sodium citrate njenge-agent yokunciphisa, kunye nezinye izinyithi ezincedisayo ezifana ne-lanthanide izinto ezinqabileyo zomhlaba ezifana ne-praseodymium kunye ne-neodymium.Xa kuthelekiswa ne-catalysts yendabuko, ukhetho, umsebenzi, kunye nesivuno sexesha lendawo ye-catalyst iyaphuculwa.
I-BP Amoco iphuhlise inkqubo yesigaba segesi ye-ethylene yebhedi, eyaziwa ngokuba yinkqubo ye-Leap Process, kwaye yakha iyunithi yebhedi engama-250 kt / i-fluidized bed e-Hull, eNgilani.Ukusebenzisa le nkqubo ukuvelisa i-vinyl acetate inokunciphisa iindleko zokuvelisa nge-30%, kwaye isivuno sexesha lesithuba se-catalyst (1858-2744 g / (L · h-1)) siphezulu kakhulu kunenkqubo yebhedi ehleliweyo (700). -1200 g/(L · h-1)).
Inkqubo ye-LeapProcess isebenzisa i-reactor yebhedi emanzi okokuqala, enezi nzuzo zilandelayo xa kuthelekiswa ne-reactor yebhedi esisigxina:
I-1) Kwi-reactor ye-fluidized bed, i-catalyst iqhubekile kwaye ixutywe ngokufanayo, ngaloo ndlela igalelo kwi-uniform diffusion yomgqugquzeli kunye nokuqinisekisa ukugxininiswa okufanayo komgqugquzeli kwi-reactor.
I-2) I-reactor ye-fluidized bed reactor ingatshintsha ngokuqhubekayo i-catalyst engasebenziyo kunye ne-catalyst entsha phantsi kweemeko zokusebenza.
I-3) Iqondo lokushisa lokuphendula ibhedi edibeneyo lihlala lihlala lihlala, linciphisa ukukhutshwa kwe-catalyst ngenxa yokushisa kwendawo, ngaloo ndlela ukwandisa ubomi benkonzo ye-catalyst.
I-4) Indlela yokususa ubushushu esetyenziswe kwi-reactor ye-fluidized bed yenza lula isakhiwo se-reactor kwaye sinciphise umthamo wayo.Ngamanye amazwi, uyilo olunye lwereactor lunokusetyenziselwa ufakelo lweekhemikhali ezinkulu, luphucula kakhulu ukusebenza kwesikali sesixhobo.