M UNgy nay vi s pht trin mnh m ca khoa hc k thut, cng nh s pht trin cao ca i sng x hi th nhu cu s dng cc loi vt liu k thut ngy mt cao, c bit khi cc ngun nguyn liu t nhin ang ngy mt cn kit. Cc loi vt cht tng hp hu c c nhiu u im v c,l, ho nn ngy cng c c s dng rng ri trong nhiu nghnh cng nghip khc nhau. Mt trong nhng qu trnh qu trnh quan trng trong cng nghip tng hp cc hp cht hu c l qu trnh Vinyl ho. Vinyl ho l mt qu trnh quan trng trong qu trnh tng hp cc cht trung gian nhm phc v cho qu trnh tng hp ra cc hp cht hu c cui cng. Nh qu trnh Vinyl ho, ngi ta c th tin hnh tng hp c Vinyl Axetat t Axetylen v axit Axetic trong pha kh vi xc tc axetat km. y l mt trong nhng phng php t c hiu sut cao.Vinyl Axetat l mt monome rt quan trng trong cng nghip cht do v si tng hp. Ngy nay, vi nhu cu ngy cng nhiu v cht do v si tng hp, cng nghip sn xut Vinyl Axetat ang ngy cng pht trin mnh v trong nhng nm gn y cng xut hin thm rt nhiu cng trnh nghin cu tng hp VA nhm lm cho qu trnh sn xut VA ngy mt hon thin hn. Trn th gii, vic sn xut v s dng VA cng rt khc nhau. vng Bc M, VA c sn xut da vo qu trnh axit axetic / etylen vi cng ngh tng c nh trong pha hi v lng VA to thnh c dng ch yu to ra polyvinyl axetat, nhng Ty u v Chu th li s dng qu trnh axit axetic / axetylen v lng VA to thnh c dng ch yu to ra polyvinyl alcol.Ngy nay nhu cu v s dng Viny Axetat ca cc ngnh cng nghip trong nc ni ring, trn th gii ni chung ngy mt tng. c bit t nc ta ang trong cng cuc cng nghip ho, hin i ho v c sn ngun ngun nguyn liu cho qu trnh tng hp. Ngoi ngun nguyn liu truyn thng th ngy nay ngnh cng nghip ch bin kh pht trin mnh to ra ngun nguyn nguyn liu gi gi v phong ph cho qu trnh tng hp. Do , Vit Nam vic thit k mt nh my sn xut Vinyl Axetat l mt vn cn thit v c ngha rt quan trng.

PHN 1Tng Quan l thuytA. Tnh cht ca nguyn liu:TNH CHT CA AXETYLENI.1 Tnh cht vt l, ho l. iu kin thng Axetylen l cht kh khng mu , khng c , c mi thm dng nh ete ( do c th c tc dng gy m ) . Mt s tnh cht vt l ch yu ca Axetylen : Nhit ngng t l 83,3 o C ( ti p sut 0,102 Mpa ). Nhit phn hu ti hn l +35,5 o C . Nhit nng chy l 5,585 Kj / mol . Nhit ho hi l 15,21 Kj / mol . p sut phn hu ti hn l 6,04 Mpa . Trng lng phn l 26,02 kg / kmol .Ti 00 C v p sut 101,3 Kpa : Trng lng ring l 1,173 kg / m 3 . Nhit dung ring : Cp = 42,7 j .mol-1.k-1. Cv = 34,7 j / mol-1.K-1. nht ng hc : = 9,43 Pa.s. dn nhit : 0,0187 A/ m. Tc chuyn m : 341 m/s. H s nn : 0,9909 . Entapy : 8,32 Kj / mol. Entropy : 197 j / mol.Axetylen c kh nng to hn hp n vi khng kh trong gii hn rng : t 20 % n 80 % th tch . Gii hn p sut nguy him l 0,2 Mpa . Axetylen cn c kh nng d dng to hn hp n vi vi Flo , Clo , di tc dng ca nh sng. Do trnh chy n th ngi ta thng pha thm cc kh tr , Hyr , amoniac vo thng cha axetylen khi vn chuyn. Axetylen khng b phn hy di iu kin nhit thng v p sut kh quyn .Khi chy , axetylen to ra mt lng nhit rt ln ( 1 m3 axetylen khi chy to ra lng nhit l 13,307 kcal ) , do c th ng dng vo vic hn ct kim loi. nhit mi trng v p sut kh quyn axtylen tinh khit khng b phn hu.Khi p sut vt qu p sut kh quyn th bt u xy ra s phn hu,axetylen lng c th xy ra phn hu bi nhit,do va chm hay di tc dng ca xc tc. V vy axetylen kh c th ho lng bo qun v vn chuyn c.Axetylen rn t b phn hu hn so vi dng lng ,tuy vy n li l vt liu khng n nh v kh nguy him. Mt tnh cht quan trng na cu axetylen l kh nng ho tan ca n ln hn nhiu so vi cc hyrocacbon khc. N ho tan kh tt trong dung mi c cc: 200C mt th tch nc ho tan mt th tch axetylen, ho tan gim khi nhit tng.Axetylen ho tan tt trong nhiu dung mi hu c v dung mi v c khc, 200C mt th tch axeton ho tan 24 th tch axetylen .Tnh cht ho tan tt ca axetylen trong cc qu trnh iu ch v tch n ra khi hn hp kh v lm sch mt cch d dng cng nh ng dng n vn chuyn, cha ng,bo qun. Axetylen c th lm giu t cc hn hp ca cc hydrocacbon C2 bng chng ct nhit thp. trnh s phn hu th nng dng hi khng c vt qu 42%.Khi p sut ln hn 0.5Mpa v 00C axetylen v nc to hyrat dng C2H2.(H2O) 5,8.Nu c mt axeton th hyrat c dng [C2H 2].[(CH3)2CO][H2O]17. Axetylen b hp th trn than hot tnh, silic oxit v zeolit.Cc cht hp ph ny c s dng tch axetylen t hn hp kh .Axetylen cng b hp ph trn b mt kim loi v thu tinh, dung dch keo ca paladi c th hp ph ti 460 mg C2H2 /1gPd.I.2. Tnh cht ho hcAxetylen l mt hydrocacbon khng no c cng thc phn t l C2H2, cng thc cu to l CH CH , lin kt ba trong l s xen ph ca hai lin kt c kh nng hot ng rt ln ( th hin r tnh khng no ) v mt sp . di lin kt C C l 1,20 , v ca CH l 1,06 . Vi cu to ny th C2H2 c phn ng c trng l cng hp : cng hp vi H2 , cc halogen H2O .a. Phn ng cng hp Vi H2

CH CH + H2 CH2 = CH2 CH3-CH3+ H2 tO=250300OC

Xc tc dng y l Pt hoc Pd

Vi cc Halogen : Cl2 , F2 , Br2

CH CH + Br2 H C = C Br + Br2 CHBr2 CHBr2 BRHKhi cng hp vi Cl2 trong pha kh , phn ng xy ra mnh lit v d gy ra n , do phi tin hnh trong pha lng vi xc tc l SbCl3 ( antimontriclorua) SbCl3 + Cl2 SbCl5CH CH + 2 SbCl5 CHCl2 = CHCl2 + SbCl3 Vi cc axit v c v axit hu c to thnh nhiu vinyl c gi tr

* ) CH CH + HCl CH2 = CHCl Phn ng trn xy ra trong pha hi to = 150 180OC vi xc tc l HgCl2 / than hot tnh*) Cng vi H2SO4 to thnh vinylsunfo.CH CH + H2SO4 CH2 = CH OSO3H*) Cng vi HCN to thnh acrylonitril(xc tc,t=80 ).

CH CH + HCN CH2 = CH CNXc tc l CuCl2 v NH4Cl*) Cng vi axit axetic to thnh vinylaxetatXc tc , tO

CH CH + CH3COOH CH2 = CH OCOCH3 Xc tc v nhit y tu thuc vo phn ng c tin hnh trong pha lng hoc pha hi. Phn ng ny s c ni k hn phn sau Vi H2OtO =75 100O C

CH CH + H2O xc tc CH3 CHO Xc tc y l Hg2 trong H2SO4 Khi c oxit km v oxit st nhit 360 4500C Axetylen tc dng vi nc to thnh Axeton: 2CHCH + 3H2Ohi CH3 CO CH3 + CO2 + 2H2b.Phn ng trng hp: Phn ng Dime ho trong mi trng HCl to thnh vinylaxetylen.

2 CH CH CH2 = CH C CHXc tc l Cu2Cl2 trong dung mi NH4Cl Phn ng Trime hoC600O C

3CH CH C6H6c. Tnh axit Do trong lin kt C H , m in ca Cacbon ln hn Hydro nn in t b ht v pha Cacbon , do nguyn t Hydro d dng tch ra v lm cho axetylen c tnh axit Tc dng vi Natri kim loi CH CH + 2Na NaC CNa + H2 To mui axetylenit vi kim loi CH CH + 2Me MeC CMe + H 2.I.3. iu ch Axetylen.iu ch t cacbua canxi. Cacbua canxi thu c t oxit canxi v cc trong l h quang in, phn ng xy ra mnh lit v i hi ngun nng lng in d tr ln.y l yu t quyt nh gi thnh ca axetylen sn xut c. Khi thu phn cacbua canxi bng nc ta thu c axetylen (phn ng to nhiu nhit). CaO + 3C CaC2 + CO.h quang in

CaC2 +2H2O C2H2 + Ca(OH)2. H = - 127,1Kj/mol. T mt kg cacbua canxi k thut c cha tp cht cc, oxit canxi v nhng cht khc c th thu c 230 280 lt kh axetylen .Theo l thuyt t 1 kg cacbua canxi sch thu c 380 lt C2H2. Ch bin axetylen t hydrocacbon: Ta c th thu axetylen t Metan v nhng parafin khc bng cch nhit phn nhit cao theo phn ng thun nghch sau: 2CH4 C2H2 + 3H2. H0298 =376 KJ / mol. C6H6 3C2H2 H0298 =311KJ/mol.y l phn ng thu nhit, cn bng ca chng ch dch chuyn v bn phi khi nhit khong : 1000 1300 0C trong thc t tng vn tc phn ng cn nhit ln hn 15000C i vi CH4 v 12000C i vi cc hydrocacbon lng. Trong sn phm kh thu c ngoi axetylen cn c ln nhnh parafin, olefin thp phn t ,benzen, metyl axetylen cng nh vinyl axetylen , diaxetylen . I. TNH CHT CA AXIT AXETICII.1. Tnh cht vt lAxit axetic l mt cht lng khng mu, c mi chua ca gim , c v chua , c tc dng ph hu da gy bng. Axit Axetic d ho tan trong nc, ru , axeton v cc dung mi khc theo bt c t l no. Axit Axetic tan tt trong xenluloza v cc nitroxenluloza. Khi un nng, axit Axetic ho tan mt lng nh phtpho v mt lng rt nh lu hunh. Axit Axetic cn c th ho tan c nhiu cht hu c , v c , n l hp cht rt n nh, hi ca n khng b phn hu nhit 400OC, nhit t nng l 3490 kcal/mol .Mt s tnh cht vt l ch yu ca Axit Axetic : T trng 1,049 g/cm 3 ( 20 O C ) Kt tinh nhit l 16,63 O C thnh tinh th khng mu c khi lng ring l 1,105 g/cm Nhit si l tso = 118 OC. Bng cc thng s vt l c trng ca axit axetic: i lng. Gi tr

Nhit dung ring ,Cp ( nhit 250C)1,110 J.g-1.K-1.

Nhit dung ring ,Cp (dng lng, 19,40C )2,043 J.g-1.K-1.

Nhit dung ring ,Cp ( dng tinh th, 1,50C) 1,470 J.g-1.K-1.

Nhit kt tinh195,5 J / g.

Nhit ho hi ( nhit si)394,5 J / g.

nht ( 250C)10,97 m.Pa

Hng s in mi ( nhit 200C)6,170

Ch s khc x nD201,3719

Entapy to thnh (H0298 lng)-484,50 Kj / mol

Entapy to thnh (H0298 hi)-432,25 Kj / mol

im chp chy cc kn430 C

im t bc chy465 0 C

Gi hn n trong khng kh4,0 - 16% th tch

Nhit ti hn , Tc 592,71 K

p sut ti hn , Pc5,786 MPa

Axit axetic c nhit si cao hn ru c cng khi lng phn t l v gia cc phn t axit c lin kt hydro bn vng .Axit axetic c ng dng rng ri trong cng nghip thc phm , dt v l sn phm trung gian rt quan trng trong tng hp hu c. Axit axetic c dng iu ch axeton , etyl axetat , i-amyl axetat , mt s dc phm ( nh l aspirin ), polime ( vinylaxetat , xenluloz axetat ), cht dit c Nhm axetat v crom axetat c dng lm cht cm mu trong cng nghip nhum . Dung dch axit axetic 3 6% c dng lm dm n ( thu c khi cho ln men gim cc dung dch ng , ru etylic )II.2. Tnh cht ho hc:Axit axetic c cng thc phn t l CH3COOH , l axit mt ln axit v cng thc cu to l :CH3COOH

Cc tnh cht ho hc ca n c quyt nh bi s c mt ca ca nhm cacboxyl COOH trong phn t. Trong nc , CH3COOH phn ly ( in ly )CH3COO

CH3COOH + H2O + H3O+.

So vi cc axit v c th CH3COOH l mt axit yu , Ka rt nh. Tc dng vi dung dch kim CH3COOH + NaOH CH3COONa + H2OMui to thnh s b phn hu mnh trong nc. Tc dng vi Pentaclorua Photpho ( PCl5 ) to thnh clorua axeticCH3COOH + PCl5 CHCH3 C = O + POCl3 + HCl Cl

Phn ng loi H2O to thnh Anhydrit axeticCH3COHOCH3COO HCH3COCH3COOP2O5- H2O+ H2O

Tc dng vi kim loi to mui axetat : 2CH3COOH + Mn (CH3COO)2Mn + H2.Mui ca axit axetic c gi tr s dng rt ln .Axetat km, axetat ng c s dng lm bt mu. Ngoi ra axetat st, axetat natri, axetat mangan c s dng lm xc tc cho cc qu trnh tng hp hu c. Phn ng tng hp Axeto-phenon : Cho hi ca hn hp axit axetic v axit benzoic i qua xc tc (THO2, MnO2) 400 5000C : CH3COOH + C6H5COOH C6H5COCH3 + CO2 + H2O.Axeton-phenon c mi d chu c s dng trong cng nghip hng liu sn xut x phng thm. Phn ng vi axetylen vi xc tc thu ngn nhit 70 850C to thnh etyl diaxetat: 2CH2CH3COOH + C2H2 CH3 CH - (OCOCH3)2.Di tc dng ca nhit v xc tc etyl diaxetat s phn hu to thnh axetaldehyt v anhydric axetic. CH3CH(OCOCH3)2 CH3CHO + (CH3CO)2O. Phn ng th halogen vo gc hydrocacbon90 100 ClCH2COOH + HCl

CH3COOH + Cl2 ClCH2COOH + HCl Tc dng vi ru to thnh este ( Phn ng este ha )H2SO4

CH3COOH + ROH CH3COOR + H2O Tc dng vi NH3 to thnh Amid

CH3COOH + NH3 CH3COONH4 Phn ng Decacboxyl ho to thnh axeton(xc tc MnO,t): 2CH3COOH CH3 CO CH3 + H2O + CO2 Phn ng vi C2H2 to thnh monome VinylaxetatCH3COOH + CH CH CH2 = CH OCOCH3II.3. Cc phng php iu ch Axit axetic.a. iu ch t C2H2 hoc CH4:

HC CH CH3CHO +CH3COOH H2C = CH2 CH3CH2OHb. xy ho n-butan trong pha lng :CH3 CH2 CH 2 - CH3 + 1/2 O2 2CH3COOH + H2O.c. Tng hp t metanol v oxit cacbon. CO + CH3OH CH3COOH.Qu trnh xy ho etylen v xy ho n-butan c hiu sut cao hn v t giai on hn nn khi p dng vo sn xut mang li hiu qu kinh t cao hn. III. TNH CHT CA VINYL AXETAT ( VA ).III.1. Tnh cht vt lVinylaxetat c cng thc ho hc l CH2 = CH OCOCH3 , gi tt l VA . VA l cht lng khng mu , rt linh ng , c mi ete v l cht lng c th chy c. Hi ca VA c th gy tn thng n mt bi s thu phn ca n to thnh axit axetic v axetaldehyt.Mt s tnh cht vt l quan trng ca VA : Nhit si l 72,7 OC Nhit ng rn l 84OC Trng lng phn t l 86,09 kg/kmol Trng lng ring 20 OC l 0,932 g/ml nht 20 OC l 0,42 cP Nhit chp chy cc h l khong 5 1OC Nhit ti hn l 252 OC p sut ti hn l 609 psia Nhit ho hi 72 OC l 90,6 cal/g Nhit chy l 5,75 Kcal/gVA t ho tan trong nc ( 20 OC ho tan c 2,5 g VA trong 100 g H2O , cn 50 OC th c th ho tan 2,1 g VA trong 100 g H2O ). VA c th ho tan trong ru v dietylete. nhit thng VA km n nh v d b trng hp cho ta sn phm l polyvinylaxetat , y l mt sn phm c gi tr trong nhiu lnh vc nh sn xut keo dn, sn , vecniIII.2. Tnh cht ho hc:Trong phn t VA c mt lin kt i nn VA c kh nng tham gia nhiu phn ng kt hp v trng hp Phn ng quan trng nht ca VA l phn ng trng hp theo c ch gc t do. VA nguyn cht nhit thng trng hp rt chm , nhng nu c tc dung ca nh sng hay cc peroxit th phn ng trng hp xy ra rt nhanh. VA trng hp cho ta Polyvinylaxetat ( PVA ) , l mt cht do rt c gi trCOOCH3COOCH3 CH2 CH n

n CH2 = CH

PVA dng sn xut sn c bm dnh cao , ch bin b mt da v vi T PVA ta c th iu ch ra ru polyvinylic bng cch cho VA tc dng vi kim hoc axit trong mi trng ru ( ROH )OCOCH3~ CH2 CH CH2 CH CH2 CH ~OCOCH3OCOCH3H+ ROH~ CH2 CH CH2 CH CH2 CH ~OHOHOH + CH3COOR

Ru polyvinylic l bn sn phm dng sn xut si vinylon , keo dn Khi thu phn PVA trong mi trng axit ta cn thu c ru polyvinylic

Ta c th tin hnh thu phn tng phn ( v d 50% nhm axetat ) v sn phm thu c dng lm mng v vt liu gi da . VA cn c kh nng ng trng hp vi nhiu monome khc cho ta nhng loi polime c gi tr. V d nh khi ng trng hp VA vi vinylclorua ta thu c loi cht do vinylit , loi cht do ny c dng lm mng mng , sn , vt liu tm VA tc dng vi CH3COOH to thnh etylidendiaxetatH

CH2 = CH OCOCH3 + CH3COOH CH3CH(OCOCH3 )2 Cc phn ng vi cc hp cht Hydroxy*) Trong mi trng axit mnh v xc tc l mui thu ngnHgOBF3OR

CH2 = CH OCOCH3 + 2ROH CH3 CH + CH3 CH O RBF2OOC CH3OR

Phn ng cng*) Vi CCl4 vi s c mt ca xc tc l Benzoyl peroxitBz2O2

nCH2 = CH OCOCH3 + CCl4 Cl3C[CH2CH(OCOCH3)]n Cl*) Vi CCl3Br CCl3Br + CH2 = CH OCOCH3 Cl3CCH2CHBr OCOCH3*)Vi MercaptanBF3

CH2 = CH OCOCH3 + C4H9SH C4H9SCH2CH2OCOCH3*)Vi NH3 , phn ng xy ra nhit phng2CH2 = CH OCOCH3 + NH3 CH CH3CH(OH)NH2 + CH3CONH2Nhng nu xy ra 130OC th sn phm to thnh theo phn ngCH3OHtO , PNCH3H5C2

CH2 = CH OCOCH3 + 5NH3 + + CH3CONH2 + 4 H2O.

Phn ng Oxy ho

VA b oxi ho vi hydroperoxit H2O2 di tc dng ca osmi tetraoxit to thnh Glycol aldehyt CH2 = CH OCOCH3 HOCH2CHO+CH3COOHIII.2.Tnh Hnh Sn Xut VA

Bng 1: sn lng VA c sn xut nm 1986 mt s ncNcS lng tn/nm

M1,15.10^6

Canada0,05.10^6

Chu M La Tinh0,09.10^6

Ty u0,56.10^6

ng u>0,16.10^6

Nht Bn0,58.10^6

Trung ng------

III.3.Tnh Hnh S Dng VA

Bng 2:tnh hnh s dng VA mt s nc:

B.Cc phng php sn xut Vinylaxetat:

I:PHNG PHP SN XUT VA T AXETYLEN V AXIT AXETIC:1.Khi nim chung:Qu trnh tng hp VA t C2H2 v CH3COOH da vo phn ng :CH HC + CH3COOH CH3COOCH= CH2Phn ng ny c th c tin hnh trong pha lng hoc pha kh.Vo nhng nm 70 , VA ch yu c sn xut ra da trn phn ng ny.Theo thng k nm 1968 t su cng ty ti M th M sn xut vi sn lng l 710 triu pound/nm da trn cng ngh tng hp VA t C2H2 v CH3COOH.Bng s liu v sn lng ca cc cng tyTn cng tySn lng(triu pound/nm)Ni sn xutQu trnh s dng

Air Reduction95Calvert ( Kentucky )Wacker

Borden150Geismar ( Louisiana )Borden Blaw Knox

DuPont75Niagara Falls ( N.Y )Wacker

Monsanto80Texas ( Texas )Monsanto Scientific Design

National Starch50Long Mott ( Texas )Wacker

Union Carbide

250South Charleston( W.Va )Texas ( Texas )Wacker

Wacker

Cn Ty u th sn xut VA vi tng sn lng l 530 triu pound/nm.3. Tin hnh trong pha lng 1. Phn ng chnh CH3COOH + HC CH CH3COO CH = CH2 + 28,3Kcal1. Phn ng phL phn ng cng ca axit axetic vi VA to thnh Etyliden diaxetat CH2=CHOCOCH3 + CH3COOH CH CH3CH(OCOCH3)2 ; H= 6,2Kcal1. C chCH CH + HgSO4 HC = CH HC = CHHgSO4

HC = CH + CH3COOH HgSO HgSO4 + CH2 = CH OCOCH3HgSO4

1. Xc tcXc tc dng trong pha lng l mui thu ngn ca cc axit khc nhau : axit sunforic , axit photphoric Xc tc c hot tnh tt nht l khi ta cho oxit thu ngn HgO tc dng vi axit axetic v Oleum nhit thng . tng hot tnh ca xc tc , tng kh nng chn la ca xc tc v h thp nhit ca qu trnh , ngi ta thm vo BF3. mt s nc ngi ta dng xc tc c thnh phn nh sau : ( tnh cho 1 Kg axit Axetic )HgO 4g

BF3 1,0 1,5 g

HF 0,5 g

Sau mt thi gian lm vic xc tc b mt hot tnh dn v phi em i ti sinh. 1. Nhit Nhit phn ng nh hng rt nhiu n hiu sut VA . Nhit cng cao th phn ng to ra sn phm ph cng nhiu nh : etyliden diaxetat , axetal dehyt , H2O Do khng nn duy tr nhit ln hn 80 OC . Nu nhit thp qu , vn tc phn ng nh , lng VA to thnh s b gi li trong dung dch phn ng v do d b trng hp .Vi loi xc tc HgSO4 th nhit du tr thng thng l 70 75 OC1. Vn tc axetylenVn tc axetylen thi vo dung dch phn ng phi tng i ln y nhanh VA ra khi dung dch phn ng . V vy phi cho d C2H2 v lng C2H2 cha phn ng phi c cho tun hon li. Mt nghin cu gn y cho thy rng , iu kin tt nht cho qu trnh tng hp VA t C2H2 trong pha lng l a C2H2 nhit 45OC vi tc 0,8 lt/ pht vo 240g axit axetic dng huyn ph vi 10g HgO ,5g Fe2O3 v 4g H2SO4.1. sch ca C2H2 v CH3COOHC2H2 v CH3COOH phi kh v sch. V nu c H2O th C2H2 s tc dng vi CH3COOH to thnh axetaldehyt . Trong C2H2 phi khng c cc hp cht cha lu hunh , pht pho , Arsenicv n l nhng cht gy ng c xc tc.1. Cc sn phm ca qu trnh:Sn phm ca qu trnh ngoi sn phm phm chnh l VA cn c cc sn phm ph nh : axtadehyt, axeton, metyl axetat, kh nhiu etyliden diaxetat, v nguyn liu cha phn ng ht. 3.s cng ngh ca hng petroleum raifiner:

4:nguyn l hot ng:

5.Tin hnh trong pha kh1. Khi nim chung khc phc nhng nhc im ca phng php tng hp VA trong pha lng ngi ta tin hnh tng hp VA trong pha kh. Qu trnh tng hp VA trong pha kh c pht trin t nm 1921 bi hng Consortium v c s dng vo trong cng nghip nm 1928 bi Wacker- Chemie ri sau c Farbwerke Hoechst ci tin thm. V trong sut chin tranh th gii th hai , dy chuyn thit b ca Hoechst sn xut 25 triu pound/nm. 1. Phn ng chnh CH3COOH + HC CH CH3COO CH = CH2 + 28,3 Kcal / mol.y l qu trnh xc tc d th . Xc tc cho qu trnh l axetat km (Zn(CH3COO)2) trn cht mang l than hot tnh. Phn ng c thc hin trong pha kh to = 180 220 OC v p sut thng ( p sut kh quyn )C ch ca phn ng bao gm : Cc giai on hp ph ho hc C2H2 to thnh phc . Vi ion km, sau l s tn cng ca phn t C2H2 ( c hot ho bng ion axetat ) v cui cng l tc dng vi CH3COOH.

+C2H2Zn2(CH3COO)2ZnOCOCH3+CH3COOH

Zn2(CH3COO)2 HC CH [CH = CHOCOCH [CH=CHOCOCH3] Zn2(CH3COO)2 + CH2 = CH OCOCH3Phn ng ph : VA to thnh c kh nng kt hp tip tc vi axit axetic ( CH3COOH ) to ra etylidendiaxetat, do vy s xut hin mt h phn ng song song ni tip. HC CH + CH3COOH CH2 = CHOCOCH3 Giai on u xy ra vi vn tc ln hn nhiu so vi giai on th hai, tuy nhin vn cn phi c mt lng d C2H2 so vi CH3COOH hn ch ti a s to thnh Etylidendiaxetat. S thu phn ca C2H2 to ra axetaldehyt HC CH + H2O CH3CHO Qu trnh xetn ho axit to ra xetn 2CH3 COOH CH3 CO CH3 + CO2 + H2O Qu trnh trng hp ca mt s cht trong h phn ng, kt qu l to thnh cc hp cht nha.1. Cc yu t nh hng Xc tc Xc tc dng cho phng php ny l axetat km mang trn cht mang l than hot tnh , silicagen , oxit nhm mt s nc ngi ta dng xc tc l axetat Cadimi v axetat canxi nhng hiu sut khng cao. nh my thng hp VA ca c chun b xc tc nh sau : ngm cc ht than hot tnh c kch thc t 3 5 mm bng dung dch axetat km tnh nh th no c 100 phn trng lng than ngm 15 phn trng lng kim loi km. Than sau khi ngm c em i sy 160 170OC v sau em s dng.Loi xc tc ny c th n nh trong thi gian lm vic l hai thng , sau n b mt hot tnh dn. hot tnh ca xc tc cng gim cng phi tng nhit ca qu trnh. Nhng khi nhit tng qu 230 OC th xc tc gn nh b mt hot tnh hon ton.Lng xc tc em dng cng nh hng nhiu n kh nng chuyn ho ca axit axetic. Tng lng xc tc t 10g n 30g trn 1 lt axetylen trong 1 gam th hiu sut chuyn ho tng ln. Nhng nu lng xc tc nh hn 10g v ln hn 30g th hiu sut chuyn ha li gim i.Nu lng xc tc ln hn 30g trn 1 lt C2H2 / 1 gam th xc tc bao ph trn cht mang thnh nhiu lp v s bao ph mang tnh cht c hc, t mang tnh cht ho hc , do khi nhit tng xc tc d b tch khi cht mang v b cun theo kh phn ng ra ngoi.Nu lng xc tc t hn 10g trn 1 lt C2H2 / 1 gam th n s khng bao ph b mt xc tc v do hot tnh km.Cc nguyn nhn lm gim hot tnh ca xc tc l : Axetylen b trng hp, VA trng hp to nn cc polime bao ph b mt xc tc . Axetat km b bay hi trong qu trnh phn ng. Axetylen b trng hp , phn ng ta nhiu nhit gy un nng cc b lm xc tc b phn hu. Axetylen khng sch c cha cc cht c i vi xc tc.Vn hon thin xc tc , chn xc tc c hot tnh cao, chn cht mang c phn tn ln v thch hp l vn hin cn ang c nhiu nh sn xut nghin cu.6.S cng ngh ca hng Wacker:

7:Nguyn l hot ng.

II. QU TRNH TNG HP VINYL AXETAT (VA) T C2H4 V CH3COOH ( PHNG PHP AXETOXY HO )1. Khi nim chungNgy nay , do gi thnh ca C2H2 t hn so vi C2H4 nn trn th gii ang c xu hng tm ra nhng phng php sn xut VA cho hiu sut cao tng ng vi phng php sn xut VA t C2H2 v CH3COOH nhng li s dng nguyn liu u c gi thnh r hn. V mt trong nhng phng php mi c s dng gn y l phng php tng hp VA t C2H4 v CH3COOH. Theo tnh ton ca cc nh sn xut th vic thay th C2H2 bng C2H4 trong cng ngh tng hp VA s tit kim c hn 20% gi thnh sn xut. Phng php ny da vo phn ng oxy ho kt hp Etylen (C2H4) vi axit axetic (CH3COOH), s dng xc tc l mui Paladi ( Pd2 ) : CH3COOH + H2C = CH2 + 1/ 2O2 CH3COOCH = CH2 + H2O ()Phn ng ny c th tin hnh trong pha lng hoc pha kh. D tin hnh trong pha no th vn phi cho thm mt lng mui ng (ng vai tr l cht mang) vo xc tc thc y s oxi ho Pd0 to thnh Pd2. Khi thm mui ng II vo th n s oxi ho Pd v tr v Cu. Cu rt d b oxi ho bi O2 thnh Cu2. Ni cch khc mui ng ng vai tr cht mang oxi cho Pd PdO + Cu 2 Pd2 + Cu Cu + 1/2O2 +2 H Cu 2 +H2OC hai phn ng trn u xy ra tng i mnh lit trong mi trng axit, trong PdCl2 nm dng H2PdCl4.C ch ca phn ng () bao gm cc giai on to thnh phc trung gian v s chuyn ho ni phn t ca phc ny : [PdCl4] 2 [PdCl [PdCl3(C2H4)] +C2H4+Cl

+ OAc+ Cl+C2H4+C l cis[PdCl2(OAc)(C2H4)] cis[PdCl2(OAc)(C2H4)]

+ OAc+ Cl

[PdCl3(OAc)] 2 cis[PdCl2(OAc)(C2H4)] 2. Qu trnh tng hp tin hnh trong pha lng:Qu trnh tng hp VA t Etylen trong pha lng c pht trin bi cc Hng Hoechst ( c ) , ICI ( Anh ) , Nippon Gosei ( Nht Bn ) v c ICI s dng vo sn xut thng mi vi quy m ln ti Anh v M trong vi nm gn y vi sn lng l 100 triu pound / nm.1. Cc phn ng chnh xy ra trong qu trnhCH2 = CH2 + CH3COOH + PdCl2 CH2=CHOCOCH3 + Pd + 2HCl CH2 = CH2 + H2O + PdCl2 CH3CHO + Pd + 2HCl Pd + CuCl2 PdCl2 + 2CuCl 2CuCl + 2HCl + 1/2 O2 2CuCl2 + H2O1. Cc thng s k thut ca qu trnh Qu trnh c tin hnh to = 100 300 OC Qu trnh c tin hnh p sut l 30 atm Xc tc cho qu trnh : Dung dch xc tc gm mui Paladi ho tan vi nng 30 50 mg Pd2 / l v mui ng ho tan vi nng l 3 6 g Cu2 / l ) T l C2H4 / O2 = 94,5 / 5,5 . T l ny nm ngoi gii hn n. Ngoi sn phm chnh l VA qu trnh sn xut cn c cc sn phm ph nh : etylyden axetat, n-buten (do s i me ho ca etylen) v axetandehyt,CO2.Nu gi mt t l no c nh gia axit axetic v nc (to ra trong qu trnh phn ng) th c th kt hp tng hp vinyl axetat v axetadehyt. Do qu trnh tin hnh trong pha lng nn thit b phn ng l dng thp sc kh v phi c ch to bng thp titan hoc cc vt liu chng n mn v chu c axit khc. Thit b phn ng khng c b phn trao i nhit ,nhit sinh ra trong phn ng c s dng lun un nng hn hp mi hoc lm bc hi hn hp trong thit b phn ng chnh. 3.s cng ngh:

3.nguyn l hot ng:

4.cng ngh tng hp VA t C2H4 v CH3COOH trong pha kh (USI CHEMCALS):

4.1:cc thng s k thut ca qu trnh:

5.s cng ngh:

6:nguyn l hot ng:

6:S CNG NGH SN XUT VA T ETYLEN TRONG PHA LNG:

7:NGUYN L HOT NG:

III.MT S PHNG PHP KHC III.1. Phng php tng hp VA t CH3CHO v CH3COCl10OC50OC60OC

CH3CHO + CH3COCl CCH3 CHOCOCH3 VApyridin82%HCl Cl

III.2. Phng php tng hp VA t CH2= CHCl v CH3COONa PdCl2

CH2= CHCl + CH3COO Na CH2= CHOCOCH3 + NaCl 5075OC

III.3. Phng php tng hp VA t isopropylaxetat v CH3CHO CH3COO C = CH2 + CH3CHO CH2=CHOCOCH3 + 120OCCH3

+ CH3- C - CH3 O

Phn ng xy ra trong thi gian l 4 sIII. 4.Phng php tng hp VA t ClCH2 CH2Cl v CH3COOH ClCH2 CH2Cl + CH3COOH CH2 CH2 OCOCH3 + 2HCl to

CH3COOCH2 CH2 OCOCH3 CH2 = CH OCOCH3 + CH3COOH.III.5. Phng php tng hp VA t metylaxetat , CO v H22CH3COOCH3 + 2CO + H2 (CH (CH3COO)2CHCH3 + CH3COOHPhn ng xy ra trong pha lng to = 150 OC , p sut p= 7 MPa , s dng xc tc l mui Rodi vi Metyliotua v amin.Sau (CH3COO)2CHCH3 phn hu thnh VA (CH3COO)2CHCH3 CH CH2= CHOCOCH3 + CH3COOHCH3COOH to ra c th cho tham gia vo qu trnh ti sinh ho este thnh CH3COOCH3 khi s dng CH3OH. CH3COOH + CH3OH CH3COOCH3 + H2ODo thc cht y l qu trnh s dng CH3OH v kh tng hp ( CO, H2 ) tng hp VA.Cc sn phm ph c hnh thnh trong tt c cc giai on phn ng, nn vic tch chng ra khi sn phm tinh khit l rt tn km. Do vic s dng phng php ny vo sn xut VA ph thuc rt ln vo gi tr nguyn liu ban u.C:SO SNH CC CNG NGH: