M u

ti: Cng ngh sn xut Axetylen v Axit Axetic

MC LC

TRANG

M U2A.Tnh Cht Nguyn Liu..3

I.Tnh Cht ca Axetylen.3

I.1.Tnh Cht Vt L3

I.2.Tnh Cht Ha Hc.4

II.Tnh Cht Ca Axit Axetic7

II.1.Tnh Cht Vt L...7

II.2.Tnh Cht Ha Hc9

II.3.ng dng..10

III.Tnh Cht Ca VA...10

III.1.Tnh Cht Vt L.10

III.2.Tnh Cht Ha Hc..11

III.3. Tnh hnh sn xut v ng dng.12

B.Cc Phng php sn xut Axit Axetic..14 I.Sn xut axit axetic ca hng BASF.14 II.Sn xut axit axetic ca hng Mosanto16C.Cc Phng Php Sn Xut VA...19 I.Sn Xut VA T Axetylen V Axit Axetic20 II.Sn Xut VA T Etylen V Axit Axetic...26 III.Mt S Phng Php Khc..31 IV.So Snh Cc Cng Ngh..32D. Kh nng xy dng nh my Vit Nam.36

KT LUN....38 M u Ngy nay vi s pht trin mnh m ca khoa hc k c s dng rng ri trong nhiu nghnh cng nghip khc nhau.

Vinyl 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 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 r 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.

A.TNH CHT CA NGUYN LIUI.TNH CHT CA AXETYLENI.1.Tnh cht vt 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 :

Bng I.1.Cc tnh cht vt l ca Axetylen [I,V]i lngGi tr

Nhit ngng t-83,3 c

Nhit phn hy ti hn+35,5 c

Nhit nng chy5,585 kj/mol

Nhit ha hi15,21kj/mol

p sut phn hy ti hn6,04 Mpa

Trng lng phn t26,02 kg/kmoll

Trng lng ring1,173kg/m3

nht ng hc9,43Pa.s

dn nhit0,0187A/m

Tc chuyn m341m/s

H s nn0,9909

entapy8,32kj/mol

entropy197j/mol

Nhit dung ringCp=42,7j.mol.k

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 it 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%.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 /1 gPd.

I.2.Tnh cht ha hc

Axetylen 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 Ao , v ca C-H l 1,06 A . Vi cu to ny th C2H2 c phn ng c trng l cng hp : cng hp vi H2 , cc halogen H2O .

I.2.1.phn ng cng vi H2:

CH CH + H2 HCH2 = CH +H CH-CH

Xc tc dng y l Pt hoc Pd:

CH CH +2H

EMBED Equation.3 HC-CH

Vi cc halogen:Cl,Br

CH CH+Br

EMBED Equation.3 BrHC=CHBrKhi cng vi Cl 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 SbCl(antimontriclorua)

SbCl+Cl

EMBED Equation.3 SbCl

CH CH +2 SbCl

EMBED Equation.3 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 t=150c-180c vi xc tc l HgCl/than hot tnh Cng vi HSO to thnh vinylsunfo:

CH CH + HSO

EMBED Equation.3 CH=CH-OSOH

Cng vi HCN to thnh acrylonitril(xc tc, t=80c)

CH CH +HCN CH=CH-CN

Xc tc l CuCl

cng vi axit axetic to thnh vinylaxetat:

CH CH +CHCOOH CH=CH-OCOCH

+)Xc tc v nhit y ty thuc vo phn ng c tin hnh trong pha lng hoc pha hi.Phn ng ny s c ni k hn phn sau.

vi HO:

CH CH + HO

EMBED Equation.3 CH-CHO

Xc tc y l Hgtrong HSO.

Khi c oxit km v oxit st nhit 360-450c th axetylen tc dng vi nc to thnh axeton

2 CH CH+3 HO CH-CO- CH+CO+2H

I.2.2.phn ng trng hp phn ng dime ha trong mi trng HCl to thnh vinylaxetylen

2 CH CH CH=CH-C- C CHXc tc l CuCl trong dung mi NHCl

phn ng trime ha:

3 CH CHCH

I.2.3.Tnh axitDo 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 kim loi Natri:

CH CH+2NaNaC CNa+H

to mui axetylenit vi kim loi:

CH CH+2MeMeC CMe+H

I.3.iu ch axetylen

iu ch t cacbua canxi

Cacbua 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 thy phn cacbua canxi bng nc ta thu c axetylen(phn ng ta nhiu nhit)

CaO+3CCaC+CO

CaC+2HOCH+Ca(OH), -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 1kg cacbua canxi thu c 380 lt kh CH

Ch bin axetylen t hydrocacbon:

Ta c th thu c axetylen t Metan v nhng parafin khc bng cch nhit phn nhit cao theo phn ng thun nghch sau:

2CH

EMBED Equation.3 CH+3H

CH

EMBED Equation.3 3 CH , 311Kj/mol

y l phn ng thu nhit,cn bng ca chng ch dch chuyn v bn phi khi nhit khong:1000-1300c trong thc t tng vn tc phn ng cn nhit ln hn 1500c i vi CH v 1200c i vi cc hydrocacbon lng.

Trong sn phm kh thu c ngoi axetylen cn ln nhng parafin,olefin thp phn t,benzen,metyl axetylen cng nh vinyl axetylen,diaxxetylen.

II.TNH CHT CA AXIT AXETICII.1.Tnh cht vt l

Axit axetic l mt cht lng khng mu,c mi chua ca gim,c v chua,c tc dng ph hy da gy bng.Axit axetic d ha 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 ha tan mt lng nh photpho v mt lng rt nh lu hunh.Axit axetic cn c th ha tan c nhiu cht hu c,v c.Hi ca n khng b phn hy nhit 400c,nhit t nng l 3490 kcal/mol.Mt s tnh cht vt l ch yu ca axit axetic:

Bng II..1.Cc thng s vt l c trng ca axit axetic [I,V]i lngGi tr

Nhit dung ring,C( nhit 25c)1,11 j.g.K

Nhit dung ring,C(dng lng, 19,4c)2,043 j.g.K

Nhit dung ring,C(dng tinh th, 1,5c)1,47 j.g.K

Nhit kt tinh195,5 j/g

Nhit ha hi ( nhit si)394,5 j/g

nht( 25c)10,97m.Pa

Hng s in mi ( nhit 20c)6,170

Ch s khc x n

1,3719

Entapy to thnh (

EMBED Equation.3 lng)-484,5 Kj/mol

Entapy to thnh (

EMBED Equation.3 hi)-432,25 Kj/mol

im chp chy cc kn43c

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

Nhit ti hn,T

592,71K

p sut ti hn,P

5,786 MPa

im t bc chy465c

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,xenlulozo axetat..),cht dit cnhm axetat v crom axetat c dng lm cht cm mu trong cng nghip nhum.Dung dch axit axetic 3-6% c dng lm du n(thu c khi cho ln men gim cc dung dch ng,ru etylic..)

II.2.Tnh cht ha hc

Axit axetic c cng thc phn t l CH3COOH.Cc tnh cht ha hc ca n c quyt nh bi s c mt ca nhm cacboxyl-COOH trong phn t.

Trong nc,CH3COOH phn ly(in ly)

So vi cc axit v c khc th CH3COOH l mt axit yu,Ka rt nh.

Tc dng vi dung dch kimCH3COOH+NaOHCH3COONa+H20

Mui to thnh s b phn hy mnh trong nc.

Tc dng vi Pentaclorua Photpho(PCl5) t thnh clorua axetic

CH3COOH+PCl5CH3Cl-C=O+POCl3+HCL 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 natric dng lm xc tc cho cc qu trnh tng hp hu c.

Phn ng tng hp axeto-phenol:cho hi ca hn hp axit axetic v axit benzoic i qua xc tc (THO2,MnO2) 400-500oc

CH3COOH+C6H5COOHC6H5COOCH3+CO2+H2O.Axeton-phenol c mi d chu c s dng trong cng nghip hng liu sn xut x phng thm.

Phn ng vi axetylen vi xc tc thy ngn nhit 70-80oc to thnh etyl iaxxetat:

2CH3COOH+C2H2CH3-CH-(OCOCH3)2

Di tc dng ca nhit v xc tc etyl ddiaxxetat s b phn hy to thnh axetaldehyt v anhydrit axetic

CH3CH(OCOCH3)2 CH3CHO+(CH3CO)2

Phn ng th halogen vo gc hydrocacbon

CH3COOH+Cl2ClCH2COOH+HCl

Tc dng vi ru to thnh este( phn ng este ha)

CH3COOH+ROHCH3COOR+H2O

Tc dng vi NH3 to thnh Amid

CH3COOH+NH3NH3CH3COONH4 Phn ng decacboxyl ha to thnh axeton( xc tc MnO,t)

CH3COOH+CH CH CH2=CH-OCOCH3II.3.ng dng

Axit axetic c ng dng rt rng ri trong thc t.Nay t xa xa con ngi bieets s dng axit axetic cho nghnh cng nghip thc phm l gim,sn xut bnh ko phc vc cho tiu dng.Trn 60% lng axit axetic sn xut c s dng trong cc polyme tng hp t vinyl axetat ( vinyl este) hoc ( xenlulo este).Hu ht cc poly (vinyl axetat) c s dng trong cng nghip sm v giy bc v nha plastic.Xelulo axetat c dng lm nguyn liu cho sn xut t si axetat.Axit axetic v cc axetat este c s dng nh l cc dung mi rt ph bin. Sau y l mt s thng tin v ng dng cc dn xut ca axit axetic:

Mui:

Aluminum axetat: c hai dng mui baz v mt mui trung ha Al(OH)2CO2CH3, Al(OH)2 (CO2CH3)2 v Al(CO2CH3)3 l mt mu trng c th tan trong nc v phn hy thnh anhydrit axetic v mui baz.Cc mui ny c s dng lm thuc nhum vi.

Mui amoni axetat: CH3CO2NH4 l cht khng mu,ht m c th tan ti 148g trong 100g nc.S dng sn xut axetamid mt cht dung mi hon ho v lm cht li tiu v lm tot m hi trong y hc.

Mui kim loi kim: gm cc mui ca cc kim loi Li,K,Na,Rb,Cs. tan ca cc mui ny trong nc tng ln cng vi s tng ca khi lng phn t cc kim loi ny.S dng mui ca kali trong cng nghip sn. Este:

Metyl axetat: l cht khng mu c mi thm s dng lm dung mi cho xenluloza nitrat,este v cc hp cht khc

Etyl axetat: c s dng lm dung mi cho xenluloza, mc v polyme v cn c s dng nh mt dung mi chit.

N-butyl axetat: l cht khng mu c mi thm,s dng lm dung mi trong cng nghip sn v gm s.

Axetyl clorua: l cht khng mu,mt cht kch thch mnh,rt hot ng v b thy phn khi c khng kh.c s dng trong cng nghip thuc nhum v dc phm.

Amit:

Axetamit CH3CONH2 : c dng tinh th su cnh,khng mi thm,tan trong nhiu dung mi nh nc v ru c khi lng phn t thp.c s dng lm dung mi v sn xut metylamin v cht lm mm

N-metylaxetamit: c cng thc CH3CON(CH3)2 l cht khng mu, dung mi c nhit si cao v c kh nng ha tan trong din rng l dung mi mnh.Trong nhiu trng hp dung mi ny cn c th xc tc cho nhiu phn ng (halogel ha,alkyl ha,ng vng).c dng lm dung mi ha tan tt polyme nh polyacrylat v polyeste.

Axit phenylaxetic: C6H5CH2CO2H d tan trong nc nng v kh tan trong nc lnh.c s dng trong cng nghip nc hoa v tng hp penicil.

III.TNH CHT CA VINYL AXETAT (VA)III.1.Tnh cht vt l

Vinylaxetat c cng thc ha hc l CH2=CH-OCOCH3,gi tt l l VA.VA l mt 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 thy phn ca n to thnh axit axetic v axetaldehyt.

Bng III.1.tnh cht vt l ca VA [I,V]i lngGi tr

Nhit si72,7c

Nhit ng rn-84c

Trng lng phn t86,09kg/kmol

Trng lng ring 20c0,932g/mol

nht 20c0,42cP

Nhit chp chy cc h-5-1c

Nhit ti hn252c

Nhit ha hi 72c90,6cal/g

Nhit chy5,75

p sut ti hn609psia

VA t ha tan trong nc.VA c th ha 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..III.2.Tnh cht ha hc

Trong phn t VA c mt lin kt i nn VA c kh nng tham gia nhiu phn ng kt hp v trung hp

Phn ng quan trng nht ca VA l phn ng trng hp theo gc t do.VA nguyn cht nhit nhit thng trng hp rt chm,nhng nu c tc dng ca nh sng hay cc peroxit th phn ng trng hp xy ra rt nhanh.VA trng hp cho ta cht Polyvinylaxetat(PVA),l mt cht do rt c gi tr.

VA cn c kh nng ng trng hp vi nhiu monome khc cho ta nhng loi polime c gi tr.V d:nh 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 etyleniaxetat

CH2=CH-OCOCH3+CH3COOH CH3CH(OCOCH3)2

Phn ng cngVi CCl4 vi s c mt ca xc tc l Benzoyl peroxit

nCH2=CH- OCOCH3+ CCl4CCl3[CH2CH(OCOCH3)]Cl

Vi CCl3Br

CCl3Br+ nCH2=CH- OCOCH3Cl3CCH2CHBr-OCOCH3Vi Mercaptan

CH2=CH- OCOCH3+C4H9SHC4H9SCH2CH2-OCOCH3Vi NH3,phn ng xy ra nhit phng 2CH2=CH- OCOCH3+NH3CH3CH(OH)NH2+CH3CONH2

Phn ng oxy haVA b oxy ha vi hydropeoxit H2O2 di tc dng ca osmi tetraoxit to thnh Glycol aldehyt

CH2=CH- OCOCH3HOCH2CHO+CH3COOH

III.3.TNH SN XUT V NG DNGIII.3.1.Tnh hnh sn xut VAVA c pht hin vo nm 1912 bi nh bc hc Klatte (c),vi vic tng hp c VA t axetylen v axit axetic trong pha lng.n nm 1925 qu trnh sn xut VA v PVA c pht trin mnh m,sn lng VA trn th gii tng nhanh vo nm 1965 trn th gii c 10 tn/nm VA c sn xut ra,cn vo nm 1984 t 2,7.10 tn/nm.Vo nm 1990 c 800000 tn VA c sn xut M, Nht l 550000 tn v Ty u l 660000 tn.Phng php sn xut VA t axetylen dn c thay th v axetylen rt t tin.Ngy nay trong cng nghip axetylen c thay th bng etylen.Khong 80% VA trn th gii c sn xut t etylen,cn li 20% VA c sn xut t axetylen trong pha khBng III.1.sn lng VA c sn xut nm 1986 mt s nc[VII]NcSn lng tn/nm

M1,15.10

Canada0,05.10

Chu M La Tinh0,09.10

Ty u0,56.10

ng u>0,16.10

Nht Bn0,58.10

Trung ng...

III.3.2.Tnh hnh s dng VA

VA l mt monome cho qu trnh trng hp,ng trng hp.VA c s dng cho cc qu trnh sau:

trong qu trnh trng hp polyvinyl axetat,lng VA tiu tn cho qu trnh ny chim t 55-60% tng lng VA sn xut ra.

sn xut polyvinyl,lng ny chim 13-15%

Qu trnh ng trng hp gia VA v etylen chim 8%

Trng hp to polyvinyl butyrat,lng ny chim 15%

Dng trong ph gia du nhn,trong ng trng hp,vi acrylonitryl tao si acrylic

Dng trong cc qu trnh khc VA c ha tan trong ru etylic v dietyl ete. nhit thng VA km n nh v d b trung hp cho sn phm polyvinyl axetat.y l sn phm c gi tr kinh t cao trong nhiu lnh vc

Polyvinyl axetat c tnh bm dnh cao,c ng dng trong sn xut keo dn v vecni,cc dn xut ca n nh polynimyl alcol,polyvinyl butyrat.Khi thy phaann polyvinyl axetat s thu c polyme rt thng dng l olyvinyl alcol,polyme ny c s dng lm cht nh hoa v lm cht tng nht cho dung dch nc.Thy phn mt phn polyvinyl axetat s thu c polyme d ta mng,cht ny c th dng lm gi da.Ngoi ra cc polyme ca vinyl axetat,vinyl clorua cng c s dng rng ri trong k thut.B.CC PHNG PHP SN XUT AXIT AXETIC sn xut axit axetic ngi ta c th i t cc ngun nguyn liu khc nhau,vi cc phng php khc nhau nh: phng php tng hp,phng php ha hc g, phng php vi sinh.

Tuy nhin p ng nhu cu s dng axit axetic ngy cng cao th hin nay hng sn xut ch yu l cc phng php tng hp:

Oxy ha trc tip cc hydrocacbon no

Oxy ha anxetaldehyt

Tng hp t oxit cacbon v metalnol

Ngoi ra axit cn thu c khi oxi ha cacbua hydro trong axit axetic l sn phm ph.Trong cc phng php trn th phng php quan trong v c gi tr thc t nht l phng php cacbonyl ha methalnol thnh axit axetic.I.SN XUT AXIT AXETIC CA HNG BASFT nm 1913,hng BASF m t qu trnh sn xut axit axetic t methanol v monoxitcacbon nhit cao v p sut cao:

CH3OH + CO CH3COOH H = - 138,6 KJ

Do iu kin nhit v p sut khc nghit cng vi s c mt ca cc cht n mn mnh ngn cn vic thng mi ha ca qu trnh ny.Nm 1941 Reppe chng minh hiu qu xc tc ca cc cacbonyl kim loi nhm VIII cho phn ng cacbonyl ha gm c qu trnh hydroformyl ha.iu ny dn n vic ra i v pht trin cng ngh nhit cao (2500C) v p sut cao (70Mpa) vi s c mt ca xc tc coban iodua.Qu trnh ny c BASF a vo sn xut thng mi Ludwigshafen(c).Cng sut ban u t 3600 tn/nm.n nm 1964 tng ln 10000 tn/nm v t 35000 tn/nm vo nm 1970.Nm 1981 t 45000 tn/nm v n nm 1981 t 64000 tn/nm.S cng ngh:

Cacbon monoxit,metanol(cha khong 60% dimetyl ete),xc tc tun hon, xc tc b sung v metyl iodua tun hon (t thp ra) c a vo thit b phn ng p sut cao (b).Mt phn nhit ca phn ng dng un nng s b nguyn liu,phn nhit cn li c tiu tn trong ng thot kh.Sn phm phn ng c lm lnh v a n thit b phn ly p sut cao.Kh thi c a vo thp ra (o), phn lng c gin ti p sut 0,5 1 MPa (5-10bar) trong thit b phn ly p sut trung bnh (e).Kh thot ra cng a vo thp ra; phn lng c a sang bung gin n (f).Kh t bung ny a sang thit b ra kh (p).Kh t thit b v thp ra c loi b thnh kh thi.C thit b ra kh v thp ra u s dng metanol ti sinh metyl iodua v cc hp cht iod d bay hi khc.Dung dch metanol ny c a v thit b phn ng.Thnh phn kh thi theo phn trm th tch l : 65-75 %CO; 15 - 20 % CO2; 3 -5 % CH4 v CH3OH.

Axit th thu c t bung gin n ch 45% trng lng axit axetic, 35% H2O v 20% este,ch yu l metyl axetat.Axit c lm snh trong 5 thp chng ct . Thp th nht (h) loi kh khi sn phm th;kh thot ra c a ti thit b ra kh.Cht xc tc c tch ra nh l dung dich axit axetic c c bng cch ui cc cu t d bay hi thp tch xc tc (i).Phn axit thu c a i sy kh bi qu trnh chng ng ph trong thp lm kh (k). Sn phm nh ca thp lm kh cha axit axetic,axit formic,nc,sn phm ph, chng to hn hp ng ph vi nc.Sn phm nh ny l mt h hai pha n c tch bung (g). Mt phn ca pha hu c cha ch yu este c a tr li (k), n ng vai tr l mt tc nhn ng ph.Phn cn li c a ti thp ph (n), y,phn nng c ly ra y thp,phn nh nh thp c tun hon li thit b phn ng.Pha lng v dung dch xc tc c quay tr li thit b phn ng.Phn ch yu trong thp lm kh c a ti thp lm sch cui, axit axetic c ly ra nh thp,sn phm y c a ti thp chng cn (m). Sn phm nh ca thp ny c a ti thp tch nc,sn phm y cha 50% axit propionic c a i thu hi.II.SN XUT AXIT AXETIC CA HNG MONSANTO

Theo l thuyt th cng ngh Monsanto cng gn ging vi cng ngh BASF, s khc nhau c bn l p sut tuyt i ch khong 3,5.106 Pa vi nhit khong 2000C.H thng bao gm cc phn sau: 3 phn chnh

Khu vc chun b xc tc: Ti khu vc ny h xc tc c chun b t rodiiodua mi v xc tc tun hon c thu hi li nh cc giai on x l sau phn ng.Dung dch thu hi ny trc ht c loi b cc ion kim loi c ln do qu trnh x l bng nha trao i ion.Sau n c phn hy mt phn nh un nng, ri lm lnh, kt ta thu hi cc cu t cha rodi.Cc hp cht ny s c b sung iot mi, ri ha tan trong axit axetic ri

Khu vc cacbonyl ha: Metanol c cacbonyl ha trong pha lng, trong mt thit b phn ng c khuy.Nhit ca mi trng phn ng c gi khng i nh bay hi mt phn cc tc nhn phn ng v sn phm,do tch c nhit phn ng sinh ra.Pha kh ny cha ch yu CO,Nit,CO2, metanol v metyl iodua,c lm lnh v ra bng methanol thu hi phn ln cc nguyn liu b tch theo. Dng sn phm lng ra khi thit b phn ng c x p nhanh.Cc kh c cha axit axetic,m,metyl iodua,axit fomic c a ti khu vc tinh ch.Phn lng,ch yu l phc xc tc, metyl axetat v axit axetic c lm lnh v a tr v vng phn ng.

Khu vc phn tch v tinh ch : thp chng u tin c thit k to ra phn don giu axit axetic nh tch b cc cu t nh v cc cu t nng (metyl iodua,metyl axetat). Phn on ny sau c dehydrat ha nh chng ng ph.Pha nc c thu hi nh thp c tip tc chyn sang chng phn on loi b nc d.Dng sn phm nng c x l trong thp tinh ch tp ra axit axetic bng, cn axit axetic cn ra y thp cng c thu hi trong thp chng phn on b sung tch cc cu t sn phm nng nh axit propionic.Cc thp ny u lm bng thp hp kim cao v c cha t 35 n 45 a.

S cng ngh:

Cacbon monoxit v metanol phn ng vi nhau trong thit b phn ng to axit axetic.Kh trong cc ng phn ng v lm sch c tp hp li v ra thp ra thu hi phn nh gm iodua hu c, sau tun hon li thit b phn ng.Axit axetic th c a ti thp chng phn nh.Sn phm nh nh c a v h thng lc kh,sn phm nng c a v h thng phn ng u.Axit axetic c ly ra dng bn v a n thp lm kh.Ti y nc c tch ra nh chng n gin.Sn phm nh ca thp lm kh l hn hp ca axit axetic v nc c a v thit b phn ng.Axit axetic kh t thp lm kh cho qua thp tch, axit propionic c tch ra di dng sn phm y.Sn phm nh l axit axetic c a ti thp lm sch ln cui.Axit axetic c ly ra di dng hi gia thp,sn phm nh v y c tun hon li thit b phn ng.

C.CC PHNG PHP SN XUT VINYLAXETAT Ta c cc phng php sau

1. T axit axetic v axetyle( trong pha lng v pha kh)

2. T diaxetyl ete v axetaldehyt

3. T etylen v axetic v O2T metyl axetat hoc imetyl ete vi CO v H2 trong pha lng c mt ca xc tc ng th nh mui Rh hoc kim loi qu nh Pt cho ta etylen diaxetat sau thy phn cho ta vinylaxetat v CH3COOH

Nm 1912 vinylaxetat c tng hp u tin c do nh bc hc Klate tin hnh theo phn ng sau:

CH CH+CH3COOH CH2=CH- OCOCH3+28,3 kcal

Pht minh ca Klate l da trn c s ca phn ng hydro ha C2H2 bng H2SO4 long c xc tc l mui Hg.Phn ng qua giai on trung gian to thnh ru vinylic km bn d b ng phn ha thnh Axetaldehyt

CH CH+HOH CH2=CH-OHCH3CHO

Trong phn ng tng hp VA,Klate thay (-OH) linh ng bng nhm(-OCOCH3) nn VA to thnh tng i bn vng khng xy ra phn ng ng phn ha

Hin nay trn th gii c rt nhiu phng php sn xut VA nhng c 3 phng php chnh c nhiu nc s dng l:

1. Phng php c in nht l i t axetylen(C2H2) v axit axetic (CH3COOH) c tin hnh trong pha lng hoc pha hiCH3COOH+ CH CH CH2=CH- OCOCH3,=118Kj/mol

2. Phng php mi nht l oxy ha cng hp axit axetic(CH3COOH) vo etylen(C2H4) trong cng nghip c thc hin trong c pha lng v hi

CH3COOH+1/2O2CH3OCO=CH2+H2O

1.Phng php i t axetaldehyt(CH3CHO) v anhydrit axetic(CH3CO)2O ban u anhydrit axetic cng vo axetaldehyt to thnh etyldendiaxetat sau EDA thy phn cho VA v axit axetic.Do qu trnh ny cn gi l qu trnh 2 giai on:CH3COOH+(CH3CO)2OCH3CH(OCOCH3)2CH3CH(OCOCH3)2 CH2=CH- OCOCH3+CH3COOH

Trong cc phng php trn th phng php sn xut VA i t Etylen,axit axetic v oxy c s dng rng ri vng Bc M cn Ty u v c bit l Chu th phng php sn xut VA i t axetylen v axit axetic li c s dng nhiu hn.Ngy nay cc phng php sn xut VA trong pha lng t c s dng v dn c thay th bng phng php sn xut trong pha kh,bi v cc phng php sn xut tin hnh trong pha lng thng c nng sut thp,gy hao mn xc tc,xc tc i khi rt c gy n mn thit b phn ng

I.PHNG PHP SN XUT VA T AXETYLEN V AXIT AXETICI.1.khi nim chung

Qu trnh tng hp VA t C2H2 v CH3COOH da vo phn ng:

CH CH+ CH3COOHCH3COOCH=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 6 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 I.1.1.s liu v sn lng cc cng ty[VII]Tn cng tySn lng

Tr pound/nmNi sn xutQu trnh s dng

Air reduction95Calvert(kentucky)Wacker

Borden150GeismarKnok-Blaw

Dupont75Niagara fallsWacker

Monsanto80TexasMonsanto

Nationalstarch50Long MottWacker

Union carbide250South CharlestonWacker

I.2.Tin hnh trong pha kh

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.Qa trnh tng hp VA trong pha kh c pht trin t nm 1921 bi hng Consurtium 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 2,dy chuyn thit b ca Hoechst sn xut 25 triu pound/nm.

Phn ng chnh

CH3COOH+ CH CH CH3COOCH=CH2+28,3 Kcal/moly l qu trnh xc tc d th.Xc tc cho qu trnh l axetat km

Phn 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.

CH CH+CH3COOH CH3COOCH=CH2Giai 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 thy phn to thnh axetaldehyt

CH CH+H2OCH3CHO

Qa trnh xeton ha axit to ra xeton

2CH3-COOHCH3-CO-CH3+CO2+H2O

Qa trnh trng hp ca mt s cht trong h phn ng,kt qu l to thnh cc hp cht nha

Cc yu t nh hngXc 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 tng 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.Loi xc tc ny c th n nh trong thi gian lm vic l 2 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 230oc th xc tc gn nhit b mt hot tnh hon ton.

Lng xc tc em dng cng nh hng nhiu n kh nng chuyn ha ca axit axetic.Tng cng xc tc t 10g n 30g trn 1lits axetylen trong 1 gam th hiu sut tng ln.Nhng nu lng xc tc nh hn 10g v ln hn 30g th hiu sut chuyn ha li gim.

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 mng tnh cht ha 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 it 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

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 hy.

Axetylen khng sch c cha cc cht c vi xc tc

Vn hon thin xc tc,chn xc tc c hot tnh cao,chn cht mang c phn tch ln v thch hp l vn hin cn ang c nhiu nh sn xut nghin cu. Nhit

Nhit thch hp vi loi xc tc nh trn l 180-220 oC. nhit thp hn th hiu sut km v nhit qu cao d b lm mt hot tnh xc tc

Vn tc th tch

Vn tc th tch cng nhanh (ngha l thi gian tip xc gia hn hp kh v xc tc cng ln) th mc chuyn ha cng tng.Nhng nu vn tc th tch qu nh th hiu sut VA li gim v trong kh sn phm c nhiu sn phm ph.

Vi vn tc th tch thng thng th mc chuyn ha t 60-70% T l s mol C2H2 / CH3COOHT l s mol C2H2 / CH3COOH tt nht cho chuyn ha cao nht l 8-10:1.Nhng trong thc t sn xut ngi ta cho d C2H2 t 4-5 ln,tc l t l s mol C2H2 / CH3COOH l 4:1,5:1,v tng lng C2H2 d nhiu hn na th hiu sut chuyn ho t tng m li phi tun hon mt lng C2H2 ln.

Axetylen v axit axetic phi kh trnh phn ng hydrat ho. ng thi cn phi lm sch C2H2 ht nhng cht gy ng c xc tc , nht l C2H2 c sn xut t cacbua canxi v thng cha nhiu H2S v H3P.

Sn xut VA theo phng php pha hi nu khng ch c cc iu kin k thut nghim ngt th ta c th t c hiu sut cao ( 97-98% so vi lng axit axetic hao tn )

S cng ngh sn xut VA trong pha kh

Hnh I.2.S cng ngh ca hng Wacker (pha kh)[VI] Nguyn l hot ngLng axetylen tinh khit v axetylen tun hon c trn ln vi nhau,cng vi axit axetic tinh khit v axit axetic tun hon trn ln vi nhau c a vo thit b bc hi (1).Thit b bc hi c khng ch nhit 70-80oc,p sut 0,3.106 Pa.Ra khi thit b ny y thp mt phn c un nng v a tr li y thp bi thit b un nng (5),mt phn sn phm a ra ngoi nh bm (13).Hn hp kh ra khi nh thp (1) c gia nhit bi thit b trao i nhit ngc chiu (3),sau c un nng bi thit b (5),hn hp kh ra khi (5) c nhit 170-190oc v c a vo thit b phn ng (2).Qa trnh ny din ra vi lp xc tc rn hoc lng,xc tc gm than hot tnh c tm 20-30% axetat kim.Thit b phn ng c dng ngn,chiu cao mi ngn 3,5-4m.Do phn ng tao ra VA l phn ng ta nhiu nhit nn lm cho nhit trong thit b tng ln.Do vy ngi ta ly nhit ra ngoi bng cch b tr thit b lm lnh hi lu ngoi thit b phn ng gi nhit khong 200oc.Qu trnh xy ra lin tc trong thit b ti sinh xc tc.Hn hp sn phm sau khi ra khi thit b phn ng gm c VA,DVA,C2H2 d,CH3COOH d,ncc nhit khong 200oc v c a ti thit b lm lnh (4) lm lnh sn phm bng nhit ca nguyn liu vo thp phn ng.Sau hn hp i qua thit b ct phn nh (7). thit b(7) nh thp ch yu l phn nh axetylen cha phn ng v mt s t sn phm khc c a sang thit b (8) tinh ch tr li cng vi axetylen ban u vo thit b phn ng (1).Khng kh c lm sch ngn s to nguyn t tr trong qu trnh tng hp,phn nng y gm VA v cc sn phm khc trn vi sn phm ly ra ti y thit b (7) qua bm (13) vo thit b tch sn phm nh (9).Thp (8) gm 35 a c kh axetylen,axetaldehyt,axeton....thp (9) gm 50-60 a.

trnh hin tng to polime ha vinyl axetat trong qu trnh chng ct phi thm cht c ch.To thit b tch phn nh (9),sn phm nh l phn nh c tch ra,sn phm y mt phn qua thit b un nng (5) a tr li (9),mt phn qua bm (13) vo thit b tch VA (10).nh thp (10) thu c VA thng phm,cn c cc sn phm nng khc c a vo thit b tch axit axetic (12).II. QU TRNH TNG HP (VA) T C2H4 V CH3COOH (phng php axetoxy ha)II.1.Khi nim chung

Ngy nay,do gi thnh ca C2H2 t hn so vi C2H4 nn 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+ CH=CH2+1/2 O2 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 oxy ha PdO to thnh Pd2+.Khi thm mui ng II vo th n s oxi ha Pd v tr v Cu2+.Cu+ rt d b oxi ha bi O2 thnh Cu2+.Ni cch khc mui ng ng vai tr cht mang oxi ha cho Pd

Pd+ Cu2+Pd2++Cu+Cu++1/2O2+2H+Cu2++H2O

C 2 phn ng trn u xy ra tng i mnh lit trong mi trng axit,trong PdCl2 nm dng H2PdCl2

II.1.1.Qa trnh 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) 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.

Cc phn ng chnh xy ra trong qu trnh

CH2=CH2+CH3COOH+PdCl2CH2=CH-OCOCH3+Pd+2HCl

CH2=CH2+H2O+PdCl2CH3CHO+Pd+2HCl

Pd+CuCl2PdCl2+2CuCl

2CuCl+2 HCl+1/2 O22CuCl2+H2O Cc thng s k thut ca qu trnh

Qu trnh c tin hnh t=100-300oc

Qu trnh c tin hnh p sut l 30 atm

Xc tc cho qu trnh:Dung dch xc tc gm mui Paladi ha tan vi nng 30-50 mg Pd2+

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 ha ca etylen) v axetandehyt,CO2.Nu gi mt t l no c dnh gia axit axetic v nc (to ra trong qu trnh phn ng) th c th kt hp tng hp vinyl axetat v axetaldehyt.

Do qu trnh tin hnh trong pha lng nn thit b phn ng l dng thp sc kh v phi c ch to bng 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 un nng hn hp mi hoc lm bc hi hn hp trong thit b phn ng chnh

Hnh II.1.S cng ngh sn xut VA t etylen trong pha lng [VII]Nguyn l hot ngHn hp kh gm 50% th tch kh etylen v 70% th tch oxy cng vi axit axetic (lng mi trn vi lng hi lu) c a vo thit b phn ng (1),thit b phn ng lm vic nhit 100-130 oc,p sut 30 atm.Sn phm to thnh gm c VA,CH3CHO,H2O,CH3COOH v hn hp oxy-etylen cha phn ng ht c a ra khi thit b phn ng (1) vo thit b ngng t (2),sau c a vo thit b phn ly (3).Phn hn hp kh hi lu s c dn qua thp hp th (4) v thp nh hp th (5) loi b kh CO2.Cn phn hn hp lng s c a vo thp (7) tch CH3COOH v lng CH3COOH ny c hi lu tr li thit b phn ng (1).Hn hp lng sau khi ra khi thit b (7) c a sang thp tch axetaldehyt (8) tch CH3CHO.Hn hp sau khi ra khi thp (8) gm 2 phnPhn hn hp i ra t nh thp (8) c a sang thp hp th CH3CHO (11),ti y cc cht nh s c tch ra nh thp cn hn hp y thp th c a sang thp chng phn on CH3CHO (12) thu hi CH3CHO nh thp,cn H2O y thp mt phn qua bm (6) bm ra ngoi,mt phn hi lu y thp.Phn hn hp i ra y thp (8) mt phn hi lu y thp,mt phn qua bm (6) a vo thit b phn ly (3) loi mt phn H2O.Sau hn hp tip tc c a vo thp tch H2O (9) v thp chng ct phn on VA (10) nh thp (10) s thu c VA,cn y thp l cc cht nng qua bm (6) bm ra ngoi,mt phn hi lu y thp qua thit b un nng y thp

Cn iu chnh lng nc trong dung dch xc tc c th hn ch c lng axetaldehyt sinh ra,tc l iu chnh c t l gia axetaldehyt v VA trong sn phm to thnh.

II.1.2.Cng ngh tng hp VA t C2H4 v CH3COOH trong pha khQu trnh tng hp VA t etylen v axit axetic trong pha kh c pht trin bi cc hng USI Chemicals ti M v hng Bayer ti c.Hin nay.quy trnh ny ang c hng Celanese ti M s dng sn xut VA vi cng sut 200 triu pound/nm

Cc thng s k thut ca qu trnh

Cng ngh tng hp VA trong pha kh c thc hin vi xc tc d th Pd/SiO2 vi ph gia l axetat Natri c cha mt lng mui ng nhm thc hin chc nng cht mang thc y s oxy ha Pd thnh Pd2+Pd+1/2O2+2CH3COOHPd2++H2O+2CH3COO-Pd2++CH2=CH2+CH3COOHPd+CH2=CHOCOCH3+2H+Qa trnh tin hnh 175-200oc,p sut 70-140 psi.Hn hp ban u a vo thit b phn ng gm etylen,hi axit axetic,oxy vi t l th tch ln lt l 8:4:1 v s chuyn ha ca chng sau khi qua thit b phn ng i vi etylen l 10% ,axit axetic l 20%,oxy l 60-70%,hiu sut c VA t 91-95%.Cc kh phn ng trn xc tc Pd t 0,1-2%.Sn phm ch yu l CO2,do khong 10% tylen tham gia phn ng chuyn ha thnh CO2 v cc hp cht cn li nh CH3CHO,,,chim khong 1%.

Hnh II.2.S cng ngh sn xut VA t etylen trong pha kh [VII]

Nguyn tc hot ng

Hn hp gm etylen mi v etylen hi lu cng vi axit axetic,oxy c un nng trc khi cho vo thit b un nng ng chm (1) ln 120oc,duy tr nhit trong thit b (1) l 175-200oc,p sut 70-140 psi vi lp xc tc c t cht trong cc ng.Hn hp sn phm sau c lm lnh (2) v vo thit b phn ly (3) nhm tch ring pha lng,kh.Tip theo pha kh c a qua my tng th (4) vo thp (5) ra bng glycon,hn hp i ra t y thp (5) c a ti thp gii hp th (6) nhm tch VA ra,cn hn hp i ra t nh thp (5) s c a n thit b ra bng cacbonat nng (7).Kh thot ra nh thp (7) l etylen c tun hon tr li thit b phn ng (1),cn hn hp y thp (7) c a ti thp gii hp th (6) nhm tch v loi b CO2.Vi pha lng sau khi ra khi thit b (6) c lm lnh,cng vi hn hp lng t thit b (3) a vo thp chng ct ng ph (8).Hn hp i ra t nh thp (8) c a qua thp chng phn on VA (9).III. MT S PHNG PHP KHC Phng php tng hp VA t CH2=CH-Cl v CH3COONa

CH2=CH-Cl+ CH3COONaCH2=CH-OCOCH3+NaCl

Phng php tng hp VA t ClCH2-CH2Cl v CH3COOHClCH2-CH2Cl+ CH3COOHCH2=CH-OCOCH3+2HCl

CH3COOCH2-CH2-OCOCH3CH2=CH-OCOCH3+CH3COOH

Phng php tng hp VA t metylaxetat,CO v H22CH3COOCH3+2CO+H2(CH3COO)2CHCH3+CH3COOH

Phn ng ny xy ra trong pha lng t=150oc,p sut p=7Mpa,s dng xc tc l mui Rodi vi Metylliotua v aminSau (CH3COO)2CHCH3 phn hy thnh VA

(CH3COO)2CHCH3CH2=CHOCOCH3+CH3COOH

CH3COOH to ra c th cho tham gia vo qu trnh ti sinh ha este thnh CH3COOCH3 khi s dng CH3OH

CH3COOH+CH3OHCH3COOCH3+H2O

Do 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.

IV.SO SNH V LA CHN CNG NGHNhn xt:qua nhng phng php tng hp VA trnh by trn ta thy cc cng ngh tng hp VA ngy cng pht trin v hon thin hn,i t nhiu ngun nguyn liu hn.Ngy nay cng vi s pht trin mnh m ca ngnh cng nghip ha du nn thay th phng php sn xu VA t etylen v ngun nguyn liu r tin.S dng c phn on cracking du m(cracking etan v propan),c nhiu trong kh t nhin.Ngnh khai thc v ch bin kh pht trin l ngun cung cp nguyn liu cho qu trnh ha hc pht trin nh Nga,M,c... p dng phng php tng hp VA t etylen trong pha kh vo sn xut rng ri.Bn cnh phng php tng hp VA t axetylen trong pha kh t c chuyn ha cao nhng do tnh kinh t ngun nguyn liu axetylen t nn phng php ny hin nay cc nc pht trin it c s dng

Hin nay qu trnh tng hp VA t etylen trong pha kh p dng vo sn xut bi 2 tp on cng nghip ln :Hoechst-Bayer,hiu sut thu c l 88-90% i vi etylen,98% i vi axit axetic.Kt lun:Qua cc phng php trnh by trn ta thy cng ngh tng hp VA ngy cng pht trin v hon thin hn.Trong phng php sn xut VA t etylen l kinh t nht v nguyn liu etylen tng i r tin.Hin nay sn lng vinyl axetat ch yu i t phng php ny

Mt khc qu trnh sn xut vinyl axetat t etylen li n gin,do hn ch c vn u t,Ngy nay ngi ta thc hin qu trnh trong pha kh nhm chng li s n mn thit b

Bn cnh ,vinyl axetat cn c sn xut t axetylen v axit axetic trong pha kh.Phng php ny c rt nhiu u im so vi cc phng php khc,hiu sut sn phm t 95-99% theo axit axetic v 92-95% theo axetylen.Do vy gim c lng tiu tn nguyn liu cng nh trnh c tht thot nhit

Vic s dng etylen c u im l gi thnh r.Nhng hn hp phn ng li c mt oxy nn d to ra hn hp chy n vi etylen.Ch lm vic p sut 30 atm nhng nhit khng cao 100-150oc trong qu trnh thu sn phm li c mt lng axetaldehyt.Xc tc qu trnh l dung dch mui Pd2+,Cu2+ (Cl-) do c Cl- m n gy n kim loi,mt khc khi c s gp mt ca oxy th Cu2+ b kt ta trong thit b,hiu sut chuyn ha etylen 90%.Ga thnh i hi cao hn qu trnh i t axetylen l 50% nn tn nhiu nguyn liu hn.

Vi axetylen th thit b lm vic p sut kh quyn nhit l 200-230oc xc tc axetat km trn cht mang than hot tnh.Hiu sut chuyn ha axetylen l 92-98% thi gian lm vic xc tc tng i di( vi thng) it n mn thit b.

Trong thc t sn xut,vic la chn phng php sn xut l ty thuc vo iu kin ca tng nc,tng vng nguyn liu,ngun nng lng,vn u t..

Vi ngun nguyn liu di do t than ,kh t nhin..ta c th sn xut VA t axetylen rt thun li.Sau thi gian nghin cu v c ti liu em chon s cng ngh sn xut vinylaxetat t axetylen v axit axetic trong pha kh.

S cng ngh thit k nh sau:

Hnh C.1.S thit k dy chuyn sn xut VA

Nguyn l

Axetylen mi c trn vi axetylen tun hon t kh thi v cng vi CH3COOH mi,CH3COOH tun hon c a vo thp bc hi (2) vi t l theo yu cu.Ti hn hp CH3COOH v C2H2 c un bc hi v c trn ln vo nhau.Nhit thp bc hi (2) c duy tr t 60-80oc vi p sut 4-5 psi v c khng ch nghim ngt c t l hn hp theo yu cu.Nu khng ch nhit 60oc s nhn c hn hp kh c 23% trng lng axit axetic. c th iu chnh nhit mt cch d dng ngi ta un nng bng hi nc

Hn hp kh c a sang thit b trao i nhit (3),ti y hn hp kh c un nng nh khi phn ng,ri tip tc c a sang thit b trao i nhit (4) hn hp t nhit 180-210oc trc khi vo lm vic trong thit b phn ng.Trong thit b trao i nhit c th dng hi p sut cao hoc du un nng.Hn hp kh sau khi c un nng ti nhit yu cu c a vo thit b phn ng (5).Thit b dng ng chm,trong cc ng cha y xc tc,bn ngoi c un nng bng du hoc hi nc( trong khi vn hnh trnh s qu nhit cc b ngi ta c th cho hn hp kh t di i ln trn,sau cho i ngc li t trn xung).Sau khi phn ng to sn phm,kh phn ng c lm ngui ti thit b trao i nhit (4) v c lm ngng t ti (16).ton b sn phm c a vo thng cha VA th (8).Ti thng cha (8) VA v axit axetic ngng t.kh khng ngng c a vo thit bi lm lnh bng CH3COOH thu hi mt phn kh d, y kh C2H2 s c tun hon tr li thp trn mt phn. Hn hp ngng t trong thng cha VA th (8) cha cc cht nh:VA,axetaldehyt,etyliden diaxetat,axeton v mt t kh axetylen ha tan c a vo thp tch kh v cc sn phm nh (10).Trc khi a vo thp chng (10) th ta b sung thm lng nhit cho nguyn liu.Ti nh thp (10) thu c kh v cc sn phm nh. Sn phm y thp (10) c a vo thp tch VA (11).Sn phm nh thp (11) sau khi lm lnh ta thu c VA.Cn y thp (11) l sn phm nng.CH3COOH th c a ti thp (12) tch phn nng v CH3COOH.Ti nh thp (12) ta thu c axit axetic.

D.KH NNG XY DNG NH MY VIT NAMI.YU CU c th xy dng nh my Vit Nam cn c nhng yu cu sau y: Phi ph hp vi dy chuyn cng ngh sn xut, ph hp vi quy hoch ca nh my, m bo kh nng pht trin ca nh my to iu kin cho sn xut ca cc phn xng khc trong tng lai. B tr giao thng trong v ngoi nh my sao cho thun tin. m bo an ton v sinh cng nghip v thun li trong xy dng.

II.C S XC NH A IM XY DNG

- Xc nh a im xy dng mt cch hp l s to iu kin tt cho giai

on chun b u t l c s pht trin sn xut v kinh doanh ca nh my trong giai on trc mt cng nh nh hng lu di.

- a im xy dng c la chn phi ph hp vi quy hoch lnh th, quy

hoch vng, quy hoch cm kinh t cng nghip. To iu kin ti a cng sut

ca nh my v kh nng lin kt sn xut ca nh my vi cc nh my ln cn.

- Phi gn vi cc ngun cung cp nguyn liu cho sn xut v gn ni tiu

th ca nh my. Gn cc ngun cung cp nng lng nh: in, nc, kh nn,

Nh vy s hn ch ti a cc chi ph vn chuyn, gp phn h gi thnh sn

phm v thc y s pht trin ca nh my.

- m bo kh nng cung ng cng nhn trong qu trong qu trnh xy dng

nh my cng nh trong qu trnh hot ng sau ny.

- Ph hp v tn dng ti a h thng giao thng bao gm ng b, ng

st, ng sng, ng bin v k c ng khng.

- Vic thot nc d dng, khng nh hng n ngun nc sch ca cc

khu dn c xung quanh.

- Khu t phi c kch thc v hnh dng thch hp cho vic xy dng trc

mt cng nh tng lai. Do vy khu t phi p ng nhng yu cu sau:

+ Khu t phi cao ro, trnh ngp lt trong ma ma bo, c mc nc

ngm thp to iu kin tt cho vic thot nc thi v nc mt d dng.

+ Khu t phi tng i bng phng c dc t nhin tt nht l vo

khong 0,5-1 % hn ch ti a kinh ph cho vic san lp mt bng v chi ph

ny kh ln trong ton b chi ph xy dng.

+ Khu t c chn la khng c nm trn cc vng c m khong sn

hay vng a cht khng n nh nh hin tng ng t, si mn hay ct chy

cng chu lc l 1,5-2,5 kg/cm2.Nn xy dng trn nn t st, t mng hay t i gim ti a chi ph cho vic gia c nn mng ca cc hng mc

cng trnh nht l cc hng mc cng trnh c ti trng tnh v ti trng ng ln.

- Khi chn la khu t th phi xem xt mi quan h mt thit gia khu dn

c th v khu cng nghip hn ch ti a nh hng xu ca mi trng

cng nghip n cc khu dn c, cc khu di tch lch s hay danh lam thng cnh

th nh my phi p ng c cc yu cu sau: + Phn xng b tr cch khu dn c xung quanh ti thiu 300 m. Phn xng xy dng ngoi vi thnh ph hoc trong khu cng nghip lin hp.

+ a im xy dng phi cui hng gi ch o so vi khu dn c v phi c vng cy xanh bo v hng gi ch yu hn ch ti a nhng nh hng xu.

+ Khu t phi vng h lu sng (nu c) cch bn dng nc ca khu dn c hn 500 m. Nc thi phi x l trc khi thi ra sng. Tm li cn c vo cc yu cu trn ta s quyt nh chn a im xy dng cho phn xng VA trong nh my c yu cu s dng sn phm ny. III.A IM XY DNG T cc c s trn ta chn a im xy dng nh my sn xut VA ti khu kinh t m Dung Qut Qung Ngi. Ni y c nh my lc du i vo hot ng t nm 2009. a im ny c nhiu yu t thun li cho vic xy dng nh my cng nh pht trin nh my sau ny nh:

- Mng li giao thng: Hng ng cch bin 6 km vi su v rng rt

thun tin cc tu trng ti ln cp cng v c th c nhiu tu cp cng n hng

1 ln. Hng nam l mng li giao thng quc gia c ng b v ng st.

Hng bc gip khu kinh t m Chu Lai- Qung Nam. V vy v mt giao thng s

rt thun li cho vic vn chuyn nguyn vt liu v nh my cng nh vic vn

chuyn sn phm ca nh my i tiu th.

- Hn na khi nh my lc du i vo hot ng s cung cp nguyn liu cho

nh my hot ng s gim chi ph vn chuyn nguyn vt liu cho nh my.

- Khu cng nghip ny l khu t cao ro, khng b ngp lt, dc t nhin

ca khu t khng ln, n khong 1% v vi nn t st kt hp vi nn t ong

nn m bo chu ti trng cao.KT LUN

PAGE 37

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