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7/25/2019 Bai Giang cng ngh ha du

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TRNG I HC BCH KHOAKHOA HA

Bmn Cng nghHa hc - Du v Kh---o---

GIO TRNH

CNG NGHHA DU

TS. NGUYN THDIU HNG


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CHNG I: QU TRNH ALKYL HA

Qu trnh alkyl ha l qu trnh a cc nhm alkyl vo vo phn t cc cht hu

c hoc v c. Cc phn ng alkyl ha c gi tr thc t cao trong vic a cc nhm

alkyl vo hp cht thm, izoparafin, mercaptan, sulfid, amin, cc hp cht cha lin kt

ete... ngoi ra qu trnh alkyl ha l nhng giai on trung gian trong sn xut cc

monome, cht ty ra...

1. C TRNG CA QU TRNH ALKYL HAI. Phn loi cc phn ng alkyl ha

S phn loi hp l nht cc qu trnh alkyl ha l da trn loi lin kt c

hnh thnh.

1. Alkyl ha theo nguyn t C: cn gi l qu trnh C - alkyl ha

C - alkyl ha l th nguyn t H gn vi C bng cc nhm alkyl.

CnH2n+2 + CmH2m Cn+mH2(n+m)+ 2

ArH + RCl ArR + HCl

2. Alkyl ha theo nguyn t O v S:cn gi l qu trnh O - alkyl ha v S - alkyl

ha

O - alkyl ha v S - alkyl ha l cc phn ng dn n to thnh lin kt gia

nhm alkyl v nguyn t O hoc S.

ArOH + RCl + NaOH ArOR + NaCl + H2O

NaSH + RCl RSH + NaCl

3. Alkyl ha theo nguyn t N: cn gi l qu trnh N - alkyl ha

N - alkyl ha l th cc nguyn t H trong amoniac hoc trong amin bng cc

nhm alk l chnh l mt trong nhng phng php q an trng nht tng hp


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3 C2H4 + Al + 3/2 H2 Al(C2H5)3

II. Cc tc nhn alkyl ha v xc tc

Cc tc nhn alkyl ha c th chia lm 3 nhm:

a) Cc hp cht khng no (olefin v acetylen), trong s ph v cc lin kt

ca cc nguyn t C.

b) Dn xut Cl vi cc nguyn t Cl linh ng c kh nng th di nh

hng ca cc tc nhn khc nhau.

c) Ru, ete, este, oxyt olefin l cc tc nhn m trong qu trnh alkyl ha

lin kt C - O s b ph v.

1. Tc nhn l olefin - xc tc v c ch

Trong cc loi tc nhn th tc nhn olefin c gi thnh kh r, v vy ngi ta

lun c gng s dng chng trong mi trng hp c th. Cc olefin (etylen,

propylen, buten v cc olefin cao phn t) ch yu c s dng C - alkyl ha

cc parafin v cc hp cht thm.

Xc tc: acid proton (a.Bronsted) hoc acid phi proton (a.Lewis)

C ch: ch yu xy ra theo c ch ion qua giai on trung gian hnh thnh

cacbocation. Kh nng phn ng ca cc olefin c nh gi bng mc to ra

cacbocation:

RCH = CH2 + H+ RC+H - CH3

Qu trnh ny chu nh hng ca s tng chiu di mch, phn nhnh caolefin:

CH2= CH2 < CH3- CH = CH2 < CH3- CH2- CH = CH2 < (CH3)2C = CH2

Tc nhn olefin c mch cng di, cng phn nhnh th kh nng phn ng


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Cc dn xut clo c xem l cc tc nhn alkyl ha tng i thng dng nht

trong cc trng hp O -, S -, N - alkyl ha v tng hp phn ln cc hp cht

c kim, c nguyn t; ngoi ra cn c s dng trong trng hp C - alkyl ha.

C - alkyl ha: xy ra theo c ch i in t di tc dng cht xc tc l cc acid

phi proton (FeCl3, AlCl3) qua giai on trung gian hnh thnh cacbocation:

RCl + AlCl3 R+

Cl -AlCl3 R+ + AlCl4

-

Kh nng phn ng ca cc alkyl clorua ph thuc vo phn cc ca lin ktC-Cl hoc vo bn cacbocation v s tng khi chiu di v mc phn nhnh

ca nhm alkyl tng:

CH3CH2Cl < (CH3)2CHCl < (CH3)CCl3

O -, S-, N - alkyl ha: xy ra theo c ch i nhn v khng cn xc tc

RCl + :NH3 RN+H3 + Cl

- RNH2 + HCl

Kh nng phn ng ca cc dn xut clo c sp xp theo dy:

ArCH2Cl > CH2= CH - CH2Cl > AlkCl > ArCl

v AlkCl bc I > AlkCl bc II > AlkCl bc III

Trong tng hp c kim v c nguyn t: xy ra theo c ch gc t do di tc

dng ca kim loi

4 NaPb + 4 C2H5Cl 4 Pb + NaCl + 4 C2H5

4 NaCl + Pb(C2H5)4 + 3 Pb

3. Tc nhn l cc hp cht c cha O - xc tc v c ch

Cc tc nhn alkyl ha c cha O nh ru, ete, este, oxyt olefin c th dng

trong cc qu trnh C -, O -, N - v S - alkyl ha; tuy nhin trn thc t ngi ta

s dng ch yu l cc oxyt olefin Qu trnh xy ra theo c ch cacbocation di


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Tc nhn alkyl ha Lin kt b ph v -Ho298 , kJ/mol

RCH = CH2

C- H

Car- H

O - H

84 100

96 104

50 63

RCl

Car- H

O - H

N - H

34 42

00 25

ROHO - H

N - H

0 21

21 42

CH2- CH2O O - H 88 104

CH CH O - H 100 117Nhn xt:

Cc tc nhn alkyl ha khc nhau th c hiu ng nhit khc nhau v thay i nh

sau:

CH CH CH2- CH2 > RCH = CH2 > ROH > RCl

O

Khi s dng mt loi tc nhn alkyl ha th hiu ng nhit s khc nhau theo cc

nguyn t khc nhau v s gim theo dy:

Car > C> N > O


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2. ALKYL HA THEO NGUYN T CACBON

Qu trnh C - alkyl ha ch yu xy ra vi cc hp cht thm v parafin vi nhiu

nghi thc t to ln.

I. Alkyl ha cc hp cht thm

1. Ha hc v c s l thuyt

1.1.Xc tc

o

Tu thuc vo tc nhn alkyl ha m c th s dng cc xc tc khc nhau. Cctc nhn alkyl ha hydrocacbon thm s dng ch yu trong cng nghip l

cc dn xut clo v olefin. Ru t c s dng cho qu trnh alkyl ha

hydrocacbon thm v c kh nng alkyl ha km hn. l do khi alkyl ha,

ru gy s phn r xc tc AlCl3, cn i vi xc tc proton th b lm long bi

nc sinh ra trong qu trnh phn ng. Trong c hai trng hp u dn n gim

hot tnh xc tc v phi tiu hao mt lng ln xc tc.

Khi tc nhn l cc dn xut clo:xc tc hu hiu nht l cc acid phi proton,

ph bin nht l AlCl3. Hn hp phn ng trong pha lng khi alkyl ha vi xc

tc AlCl3bao gm 2 pha: phc xc tc v lp hydrocacbon.Khi dng loi xc tc ny cn lu : cc tc nhn tham gia phn ng cn phi sy

trc khi s dng v trong qu trnh tin hnh phi trnh khng cho nc lt vo

mi trng phn ng; bi v nc c kh nng lm phn r mt phn xc tc dn

n lm gim hot tnh xc tc

Khi tc nhn l olefin: thng dng xc tc l AlCl3; ngoi ra c th dng

a.H2SO4, HF, H3PO4trn cht mang, aluminosilicat, zeolit... Trong :

o Khi xc tc l a.H2SO4hoc HF: + qu trnh pha lng


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+ p = 2 - 6 MPa

Nh vy, i vi qu trnh C - alkyl ha th xc tc AlCl3chim v tr p o v

c nhiu u th.

AlCl3 trng thi rn hu nh khng tan trong hydrocacbon v xc tc rt yu

cho phn ng. Tuy nhin theo mc hnh thnh HCl, AlCl3bt u chuyn qua trng

thi lng c mu sm. Cht lng ny mc d khng tan trong hydrocacbon nhng c

hot tnh rt ln v do tc phn ng s tng ln. Trng thi hot ng ca AlCl3c

th chun b bng cch sc kh HCl qua h huyn ph ca AlCl3trong hydrocacbon, khi

s hnh thnh phc ca AlCl3v HCl vi 1 n 6 phn t hydrocacbon thm, trong

mt phn t ny nm trng thi cu trc c bit mang in tch dng (phc )

cn cc phn t cn li hnh thnh lp solvat:

Nhm t c vn tc alkyl ha cao ngay t thi im bt u phn ng, phc

ny thng c chun b trc ri sau a vo h phn ng.

1.2.C ch phn ng1.2.1. Khi tc nhn l dn xut Clo RCl:xc tc AlCl3s hot ha Cl to ra phc

phn cc mnh (phc ) v hnh thnh cacbocation

RCl + AlCl3 R+

Cl -

AlCl3 R+ + AlCl4

-

1.2.2. Khi tc nhn l olefin: xc tc AlCl3s kt hp vi cht ng xc tc l HCl

R

R+ H

R

+ R+ + H+

. (n-1) ArHHH

Al2Cl7-


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Nu tc nhn l propylen s to ra alkylbenzen bc II l isopropylbenzen:

Nu tc nhn l iso butylen s to ra alkylbenzen bc III l ter butylbenzen:

1.3.Cc phn ng ph

Cc phnng ph c th xy ra trong qu trnh alkyl ha ha hydrocacbon thm

l:

Alkyl ha ni tip

Nha ha

Phn hy cc nhm alkyl

Polyme ha olefin

Phn ng alkyl ha ni tip:

Khi alkyl ha cc hp cht thm vi s c mt ca xc tc bt k s xy ra s th

ni tip cc nguyn t H v to thnh hn hp sn phm vi mc alkyl ha khc

nhau.

V d khi etyl ha C6H6s xy ra n khi to thnh hexa etylbenzen:

Mi phn ng trong dy ny u l cc phn ng bt thun nghch. Tuy nhin khi

dng xc tc Aluminosilicat hoc Zeolit iu kin tng i khc nghit hoc khi

+ C6H6+ H+

CH3- CH = CH2 CH3- C+H - CH3 C6H5- CH (CH3)2

+ H+

+ C6H6+ H+

(CH3)2- C = CH2 (CH3)3 - C+

C6H5- C (CH3)3 + H+

C6H6 C6H5- C2H5+ C2H4 + C2H4

C6H4- (C2H5)2+ C2H4

C6H3- (C2H5)3 v.v.


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Cc kh nng hnh thnh sn phm ni tip:

Cc gii php a ra lm gim lng polyalkylbenzen:

1.

Dng xc tc aluminossilicat hoc Zeolit iu kin tng i khc nghithoc AlCl3

2. Gim lng tc nhn olefin v tng lng benzen vi t l mol :

Tuy nhin phng php ny c nhc im l chi ph chng ct v

hon lu li lng benzen d kh cao

3. Cho hi lu cc polyalkylbenzen tr li thit b phn ng khi s c s

alkyl ha li vi benzen to ra sn phm monoalkyl mong mun. iu

ny cho php tng ng k tnh la chn v lm vic t l = 0,3 - 0,5;ng thi gim ng k lng benzen d, gim chi ph trong vic chng

ct v hon lu benzen.

Phn ng nha ha

+ R+

+ R+

RR

+ R+

R

R R

R+ R

+

RR

R

RRR

R

RR

=mol tc nhn olefin

mol benzen= 0,1 - 0,2


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+ Khi C2H4phn ng vi C6H6c hnh thnh sn phm C6H5-CH3.

Mch alkyl cng di cng d b phn hy. S phn hu c kh nng xy ra giai

on tch cacbocation.

Phn ng polyme ha olefin

Nguyn nhn: l do s kt hp ni tip ca cacbocation vi olefin (trng hpcation)

Polyme sinh ra c khi lng phn t khng ln v c th hn ch bng lng d

hydrocacbon thm v gim nng olefin trong pha lng.

2. Thit b phn ng

Hin nay c 3 loai thit b phn ng lin tc alkyl ha cc hydrocacbon thm vi

xc tc AlCl3.

Alkylat

R

+ 2 C6H6

- H+

RC+H - CH2R RCH = CH2 + R+ C6H5- CH - CH3 + C6H5R

+ C2H4CH3- C

+H2

CH3- (CH2)2- C+H2

+ C2H4

CH3- (CH2)4- C+H2 ....

kh

olefin

Alkylat

C6H6

tc nhn

alkyl haXc tc

H2O

H2O

Alkylat


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nc). Trng thit b tch, lp hydrocacbon c tch khi lp phc xc tc v sau

a vo x l. Thi gian lu ca hn hp trong thit b phi m bo kt thc phn

ng.

b. H thitb ni tip: bao gm t 2 n 4 thit b phn ng c cnh khuy. Cc tc

cht ban u c a vo thit b phn ng u tin v hn hp phn ng sau t bn

hng s chy qua thit b phn ng tip theo. Gia 2 thit b ny c b phn tch s b,

trong phc xc tc tch ra c a tr li thit b phn ng u tin. Khi s dng h

thit b ni tip s trnh c hin tng tiu hao xc tc ln trong sn phm. Thi gian

lu ca hn hp phn ng trong h thit b ni tip l khong 50 pht nhit 40 -

60oC, ngoi ra thi gian ny cn c xc nh bi cc iu kin gii nhit v yu cu

cn t n cn bng sao cho cc sn phm monoalkyl l cao nht.

c. Thit b dng ng: loi thit b ny dng alkyl ha cc hydrocacbon thmbng tc nhn olefin dng kh. Hn hp lng bao gm phc xc tc AlCl3(20 - 40% th

tch) v hn hp hydrocacbon khng tan trong n c a vo thit b ti mc van tro

bn hng. pha di a vo C6H6khan v phn on olefin c sc qua cht lng

c km theo khuy mnh. Hn hp lng s chy qua van tro i vo b phn tch, sau

thi gian lng t nhin lp xc tc nng hn pha di s c a tr li thit b phn

ng cn phn sn phm alkyl ha s c a i x l tip.

Nhit ca phn ng hu nh c thot ra bi vic lm nng cc tc nhn v lm

bc hi benzen. Hi benzen cng vi kh ca phn ng c a qua sinh hn, ti y

benzen s ngng t v s quay tr li thit b phn ng, cn kh c a i x l tip.Nh vy trong thit b ny ch nhit gn nh l thit lp mt cch t ng v nhit

s ph thuc vo p sut cng nh lng kh thot ra (hoc ph thuc vo nng ca

phn on olefin ban u)


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Etylbenzen gy bng da v mt, trong mt gii hn no cng gy c qua

ng h hp v n ung, ng thi hp ph qua da.

Hu ht etylbenzen (>99%) c s dng sn xut monome Styren (C6H5-

CH=CH2) v n l hp cht ch o m bo iu kin k thut cng nh thng mi

cho qu trnh sn xut styren. y l mt monome rt quan trng trong lnh vc sn xut

cht do v cao su tng hp. Ch c khong 1% etylbenzen c s dng lm dung mi

pha sn hay lm hp cht trung gian sn xut dietylbenzen v acetophenol.

2.1.2. Cng ngh

Hin nay hu ht etylbenzen sn xut trong thng mi u t qu trnh alkyl ha

benzen bng etylen. S sn xut etylbenzen tiu th 50% lng benzen trn th gii.

Qu trnh alkyl ha ny c tin hnh ch yu theo 2 phng php:

- Tin hnh trong pha lng vi xc tc AlCl3

- Tin hnh trong pha hi vi xc tc rn tng c nh

Phn ng : y l phn ng ta nhit mnh

C6H6 + C2H4 C6H5- C2H5 -H0

298= 114 kJ/mol

a. Qu trnh pha lngT nhng nm 1930, cng ngh alkyl ha pha lng vi xc tc AlCl3 c

a vo s dng vi nhng c tnh u vit. Nhiu cng ngh pht trin da trn s

ci tin qui trnh cng ngh ban u ny, tuy nhin n hin nay qui trnh ca Monsanto

s dng xc tc AlCl3l qui trnh thng mi hin i nht.

Qu trnh alkyl ha benzen bng etylen trn xc tc AlCl3 l mt phn ng ta

nhit xy ra rt nhanh v phn ln to thnh etylbenzen. Ngoi xc tc AlCl 3 cn c

nhiu xc tc acid Lewis khc c s dng nh AlBr3, FeCl3, BF3. Ngoi ra ngi ta


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Thng th mt lng nh HCl m bo hot ha AlCl3, gii hn s n

mn ca HCl ngi ta s dng cht kch ng l etylclorua C2H5Cl.

*iu kin vn hnh phn xng:

Nguyn liu benzen phi sy kh trc khi s dng (< 30 ppm H 2O)

Nhit t = 160 - 1800C tng ng vi p sut tuyt i p = 1.106Pa

iu chnh t s = benzen / nhm etyl = 2 - 2,5 hiu sut thu sn phm ti a.

VVH = lng benzen / lng xc tc /h 2Thu hi nhit ta ra sn xut hi nc p sut thp nhm gim nhit phn

ng, gip cn bng dch chuyn theo chiu thun.

* S cng ngh: Hnh 2

C2H4

C6H6

hi lu

C6H6

N2

h

h

ga

b

f

c

de

h

AlCl3

H2O

i

EB hi luKh thiNH3

EB th ilm tinh

mui thi

Poly etylbenzen hi lu


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a vo thit b phn ng t di ln qua b phn phn phi. Dng lng i ra khi thit

b phn ng c trn vi dng poly alkylbenzen hi lu i vo thit b chuyn v alkyl

(d). So vi cng ngh trc y, cng ngh ny poly alkylbenzen khng c hi lutrc tip v thit b phnng do s hi lu vi mt lng ln vi nng xc tc thp

s lm ngng phn ng alkyl ha. Ngi ta s dng mt thit b chuyn v alkyl ring

(d), trong thit b ny nhit cng thp hn nhiu so vi thit b alkyl ha (b) qu

trnh thu etylbenzen t nng sut cao hn. Sau khi ra khi thit b chuyn v alkyl (d),

dng c a n mt thp tch, ti y kh i ra nh cn dng lng c lm lnh

v a vo thng lng (g). Ti (g) pha nng lng ra khi pha lng c tch ra mt phn

hi lu liqu trnh , cn phn lng nh c a qua h thng cc ct phn tch lm

sch (h). i vi qu trnh ng th, tt c xc tc u vn cn trong dung dch, sn

phm c ra bng nc v amoniac. Dng alkylat th tip tc a qua b phn tinhch thu etylbenzen tinh khit.

Qu trnh tinh ch thu etylbenzen tinh khit c thc hin trong 3 ct chng

tch:

Benzen khng phn ng c thu hi nh ct chng ct u tin, dng y ct 1

c a qua ct chng ct 2.

ct 2, etylbenzen c chng tch ra khi phn poly alkylbenzen nng hn, y

ct 2 c a qua ct cui cng. nh ct 2 thu c etylbenzen vi tinh

khit ln hn 99% (c th t 99,8%)

Ti ct 3, chng ct poly alkyl bng stripping v cho hi lu v u qu trnh,nhng hp cht cn hay du cha ch yu l cc hp cht thm a vng c s

dng lm nhin liu.

b. Qu trnh pha hi


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+ sn phm c tinh khit cao

Nhc im: mt lng rt nh nc (>1 mg/kg) s lm thu phn xc tc

BF3gy n mn thit b, do cn loi b nc cng nh cc hp cht

cha S, O trong nguyn liu trc khi a vo qui trnh.

iu kin vn hnh:

+ nguyn liu: benzen kh, etylen v BF3

+ p sut cao: 25 - 35 bars+ nhit thit b phn ng thp; 100 = 1500C

+ etylen/benzen= 0,15 - 0,2

+ nhit thit b chuyn v alkyl = 180 - 230oC

Kt qu thu etylbenzen c nng 99,9%.

* Nm 1970, cng ngh ca Mobil - Badger xut hin v c cng nhn l cng

ngh alkyl ha trong pha hi thnh cng nht vi xc tc zeolit tng hp ZSM-5.

u im:

+ h xc tc d th em li nhiu thun li: xc tc cha ch yu Si-Al nn

tr, khng gy n mn v khng gy nhim mi trng, khng cdng lng d nn khng cn thit bi x l cht thi cng nh thit b thu

hi xc tc. Thit b ch cn ch to bng thp cacbon m khng cn

hp kim cao v gch lt.

+ sn phm c tinh khit cao

Nhc im: qu trnh cho hiu qu kinh t khng cao bng cng ngh

alkyl ha trong pha lng.

iu kin vn hnh:


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c. Cng ngh sn xut etylbenzen mi hin nay:

Hin nay cng ngh xc tc zeolit, pha lng, tng xc tc c nh ca

Lummus/UOP l cng ngh sn xut etylbenzen hin i nht c nhiu u im.

Cng ngh ca qui trnh cng da trn qui trnh alkyl ha trong pha lng c bn

nu trn, im ng ch l xc tc s dng l xc tc zeolit khng n mn v khng

c hi, c th ti sinh ngay trong thit b phn ng hay em i ti sinh mt c s

khc; v vy s ny khng cn h thng ra v trung ha sn phm.

u im:

+ p ng yu cu v sn lng d dng

+ tinh khit sn phm cao > 99% (m); sn phm ph xylen rt t, trnh c s

kh khn trong vic phn tch tn nhiu kinh ph, thch hp dng lm nguyn

liu sn xut Styren.

+ tiu th nguyn liu t

+ chi ph u t thp

+ vn hnh an ton, d dng+ hiu sut 99,5%

S cng ngh: hnh 3

Etylen, benzen mi v benzen hi lu t nh thp tch benzen (3) c a vo

thit b phn ng alkyl ha (1) vi xc tc zeolit, phn ng xy ra to thnh hn hp

alkylat. Dng sn phm c a qua thp tch benzen d v poly etylbenzen (3), mt

phn cho hi lu v thit b chuyn v alkyl (2) to etylbenzen b sung, mt phn c

a v u qu trnh (1). Ti thp tch (3), phn y gm etylbenzen, poly etylbenzen v


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Hnh 3: Cng ngh xc tc pha lng, tng xc tc c nh Lummus/UOP

1. Thit b phn ng alkyl ha - 2. Thit b chuyn v alkyl - 3. Thp tch benzen -

4. Thp tch Etylbenzen - 5. Thp tch poly etylbenzen

2.2. Tng hp iso propylbenzen

Iso propylbenzen C6H5-CH(CH3)2 cn c tn gi khc l Cumol, iu kin

thng tn ti dng lng c ts= 152,5oC.

ng dng:

+ t iso propylbenzen s thu c mt monome quan trng trong lnh vc cao sutng hp l -metylstyren C6H5-C(CH3)=CH2

+ t iso propylbenzen tng hp iso propylphenyl hydroperoxyt (cn gi l

h d t l) C H C(CH ) OOH t th t h h l t

C6H6hi lu

C6H6

C2H4

1

2

3 4 5

Phn nng

Etylbenzen

OOH


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Trong phm vi Cng ngh Ha du, qu trnh alkyl ha parafin tp trung ch yu sn

xut i-octan vi sn phm chnh l 2,2,4_trimetylpentan. y l cu t chun c RON =

100 dng trong php th xc nh ch s octan ca xng nhin liu.

Phn ng: i-C4H10 + n-C4H8 i-C8H18

1. Ha hc v c s l thuyt

Nguyn liu: iso butan

Tc nhn alkyl ha: n-butenXc tc: HF khan hay H2SO494 - 96% (m) hay AlCl3

Ch cng ngh: qu trnh alkyl ha i-parafin bng mt olefin l mt qu trnh

to nhit km theo s gim th tch; do vy khi gim nhit tng p sut s

thun li cho qu trnh. ng thi nhit qu trnh phi chn sao cho hn ch

ti a cc phn ng ph m vn duy tr vn tc phn ng chnh mc cao.

Tuy nhin cc thng s ny tu thuc vo loi xc tc s dng:

Xc tc l H2SO4: t = 4 10oC

p = 3 4 at

tx= 20 30 phtXc tc l HF : t = 20 35oC

p = 6 8 at

tx= 10 20 pht

Xc tc l AlCl3: t = 50 60oC

p = tng i dng

C ch: phn ng xy ra theo c ch cacbocation

Ban u olefin tham gia to ion cacboni:


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Cacbocation mi to thnh d b chuyn v ni phn t vi s di chuyn v

tr ca H vcc nhm CH3- v cui cng, cc cation ny tc dng vi i-

butan s to ra hn hp cc i-octan v ter - butylcation:

Cation ny (CH3)3C+ thc y qu trnh theo c ch chui ion. Thnh phn cc

isome ph thuc vo bn ca cc cacbocation trung gian v vn tc phn ng trao ica chng vi i - butan.

Cc phn ng ph:

Phn ng alkyl ha ni tip - song song

2,3,3-trimetylpentan




CH3- C - CH - CH+- CH3

CH3 CH3

CH3

CH3- C - CH+- CH

CH3 CH3

CH3 CH3

CH3- C+- CH - CH

CH3 CH3

CH3 CH3

CH3- C - C+- CH2

CH3 CH3

CH3 CH3

CH3- C+ - C - CH2

CH3 CH3

CH3 CH3

(CH3)3CH(CH3)3C

+

CH3- C - CH2- CH

CH3 CH3

CH3 CH3

CH3- CH - CH - CH

CH3 CH3

CH3 CH3

CH3- C - CH - CH2

CH3 CH3

CH3 CH3

CH3- CH - C - CH2

CH3 CH3

CH3 CH3


20/185

Trong cc alkylat thu c bao gi cng c mt cc parafin thp v cao phn t

vi s nguyn t Cacbon khng l bi s so vi s nguyn t cacbon trong nguyn liu

ban u.

V d, khi alkyl ha i-butan bng cc buten th alkylat cha 6-10% hydrocacbon

C5- C7v 5- 10% hydrocacbon C9hoc cao hn.Nhng sn phm ny ch c th sinh ra

bi cc qu trnh phn hu, nht l khi tng nhit .

Phn ng trng hp

Phn ng ny xy ra do s trng hp cation ca olefin hnh thnh cc polyme

thp phn t c cha ni i. iu ny s lm gim cht lng ca alkylat v tiu tn

nhiu xc tc, bi v cc phn ng ny cng xy ra vi s c mt ca xc tc acid:

T l gia i-parafin v olefin:

Khi s dng lng d i-parafin so vi olefin s hn ch ton b cc phnng ph

v c nh hng tt n hiu sut alkylat, tng hm lng sn phm mong mun, tng

ch s octan ca sn phm v gim tiu hao xc tc. Tuy vy cng khng nn dng

lng d qu ln i-parafin v khi chi ph ti sinh sau s rt cao.

T l mol ti u trong trng hp ny gia i-parafin v olefin t 4:1 n 6:1.

Thit b phn ng

Hn hp phn ng l h hai pha c phn tn vo nhau nh cnh khuy hay h

thng bm phn tn.

C hai loi TBP c s dng khc nhau bi phng php gii nhit:

Loi lm lnh bn trong bi amoniac lng (hoc propan): phn ng c thc

hin trong thit b alkyl ha c gn my khuy cng sut ln v cc ng lm lnh.

2 C4H8 C8H16 C12H24....

+ C4H8+ H+


21/185

qua vch ngn vo khoang th hai v tip tc nh vy. Khoang p cui s lm

nhim v tch acid khi hydrocacbon, v acid ny c a tr li phn ng

alkyl ha. Hn hp hydrocacbon sau khi qua vch ngn cui cng s c i xl tip.

2. S cng ngh

Ngi ta a vo khoang u ca thit b phn ng (4) i-butan lng, a.H2SO4

(lng mi cng lng hi lu), cn n-buten c a vo tng khoang ring r. Do

nhit ca phn ng sinh ra mt phn i-butan s b bay hi. Hi ny s i vo bnh cha

(2), ng vai tr va l bnh tch va l bnh trn. Kh t bnh ny c tip nhn lin

tc bi my nn (1) (nn n p sut 0,6 MPa) v ngng t ti thit b ngng t (3).

Trong thit b chnh p sut (5) p sut c gim xung khong 0,2 MPa, ti y mt

phn i-butan c bay hi v tch ra trong bnh cha (2). T (2) i -butan lng li ca tr li thit b alkyl ha.

NaOH4

n-C4H8

7

C3H8

132

1

3 11

6

5

9

13

alkylat

11

10

C4H10

12


22/185

Trong qu trnh hot ng lin tc, trong i-butan s xut hin propan do cc

hydrocacbon b phn hy haydo hin din ngay trong nguyn liu ban u. V vy trong

chu trnh lm lnh i-butan c mt cng on tch propan bng ct chng phn on (6).Ngi ta a vo mt phn i-butan hi lu sau sinh hn (3) v i-butan c lm

sch khi propan s quay tr v bnh cha (2).

Hn hp i ra t khoang cui thit b alkyl ha (4) c cha i -butan d, octan,

hydrocacbon C5- C7v cc hydrocacbon cao phn t khc. Hn hp ny c a vo

thit b tch (7) tch phn acid cn li. Acid c a tr li thit b alkyl ha, tuy

nhin mt phn ny s c thi ra ngoi, s b vo mt lng acid mi. Lp

hydrocacbon t thit b tch (7) c trung ha bng dung dch 10% trong thit b (8)

sau tch ra khi lp nc trong thit b tch (9). Hn hp hydrocacbon trung tnh

c a i chng ct ti ct chng phn on (10). Ti ct ny phn on i-butan mic a vo. Mt phn i-butan c a tr li thp chng (10), cn phn ln s a

qua thng cha (2) v t y i vo thit b phn ng. Nh vy s thc hin mt chu

trnh vn chuyn ca i-butan. T sn phm y ct chng (10) s thu c alkylat sn

phm.

3. ALKYL HA THEO NGUYN T OXY, LU HUNH V NIT

Cc qu trnh O- alkyl ha , S- alkyl ha v N- alkyl ha l cc phng php c

bn tng hp cc hp cht vi lin kt ete, mercaptan v amin.

I. O- alkyl haTrong s cc qu trnh O- alkyl ha c 2 qu trnh c ng dng trong sn xut

cng nghip: alkyl ha ru v phenol bng cc dn xut Clo; alkyl ha ru bng

olefin Trong qu trnh alkyl ha ru bng olefin c s dng rng ri sn xut


23/185

C2H5Cl + NaSH C2H5SH + NaCl

C5H11Cl + NaSH C5H11SH + NaCl

Etylmercaptan - nguyn liu trong sn xut mt loi thuc tr su ni ting

l Mercaptophos, c tng hp t qu trnh alkyl ha Hydrosulfid natri

bng dn xut Clo l Etylclorua:

Etylmercaptan, Pentylmercaptan c s dng lm cht to mi cho kh

t dn dng. Pentylmercaptan c tng hp t qu trnh alkyl ha bng

Clopentan:

Ngoi ra cn mt vi mercaptan khc c ng dng trong tng hp cc cht ty

ra khng ion, hay trong qu trnh tng hp cao su nhn to....

III. N- alkyl ha

alkyl ha ammoniac hoc amin theo nguyn t nit ngi ta t dng Olefin

bi v khi ch to mt lng nh amin, cn sn phm chnh s l nitril . Thng thng

ngi ta thng s dng tc nhn alkyl ha l cc dn xut Clo v ru, trong ru

c s dng nhiu hn, bi v cc dn xut Clo t tin hn.

Cc amin ph bin nht l:

Metylamin CH3NH2(ts- 70C), Etylamin C2H5NH2(ts= 15

0C),

Dimetylamin (CH3)2NH(ts= 70C), Dietylamin (C2H5)2NH (ts= 56

0C),

Trimetylamin (CH3)3N (ts= 40C). Trietylamin (C2H5)3N (ts= 90

0C).

Tt c cc hp cht ny u c th trn hp vi nc bt k t l no,

vi khng kh chng to thnh hn hp d n,

v cng nh cc amin khc chng l nhng cht rt c,

Chng c dng lm nhin liu lng cho cc ng c tn la (nh Metylamin,


24/185

Ch cng ngh: cc qu trnh c gi tr cao trong sn xut cng nghip khi

thc hin :

Pha kh

Nhit : 350 - 4500C

Xc tc: xc tc dng acid nh Oxyt nhm Al2O3; aluminosilicat; ....

C ch: tc dng ca xc tc d th th hin s hot ha lin kt C -O

trong ru do s hp ph ha hc trn cc tm acid ca chng:

Phn ng ph:

Phn ng dehydrat: do xc tc cho qu trnh l xc tc acid, m loi xc tc ny

cng c kh nng thc y phn ng tch nc ca ru dn n s to thnh ete

v olefin:

2 ROH ROR + H2O (1)

RCH2- CH2OH RCH=CH2 + H2O (2)

Phn ng alkyl ha ni tip - song song: phn ng ca ammoniac vi ru, cngnh vi cc dn xut Clo l qu trnh ni tip - song song km theo s th lin

tip cc nguyn t H ca ammoniac. Kt qu l sinh ra hn hp amin bc nht,

bc hai v bc ba.

.

Phn ng chuyn v cc nhm alkyl:

ROH + H+ RO+H2 RN+H3 RNH2 + H

++ NH3

- H2O

NH3+ ROH

- H2O RNH2+ ROH

- H2O R2NH+ ROH

- H2O

2 RNH2 R2NH + NH3


25/185

Cc kh nng s cung cp nhit ca mnh cho hn hp ban u trong thit b trao i

nhit (2) v sau em i x l tip tc.

Cc sn phm thu c s phn tch bng chng ct phn on, mi giai ons thit lp p sut sao cho thu c on hi lu lm lnh bng nc. Trc ht trong

thp chng (4) ngi ta chng tch ammoniac v n c a li thit b phn ng. Sn

phm y c a qua thp chng (5) v chng ct cng vi nc (do s c mt ca

nc lm cho bc hi tng i ca trimetylamin (TMA) tr nn rt cao so vi cc

metylamin khc). Mt lng nh TMA chng tch ra c xem l thnh phm nhng

phn ch yu c hon lu li thit b phn ng. Hai amin cn li c nhit si khc

bit ln hn (-70C v 70C) s c tch ra bng chng tch phn on thp chng (6)

v (7). Mi sn phmny ly ra t nh thp c th xem nh l thnh phm hoc tr li

phn ng tip tc. thp chng cui cng (8) s chng tch Metanol khi nc vMetanol c quay tr li thit b phn ng. Hiu sut cc amin l 95%

11 11 1111

10 10 1010

9999 9

876543

2

1

NH3(k)

CH3OH

nc thi

hi nc

DMAMMATMA

CH3OH

NH3(l)


26/185

Chng II: Qu trnh hydro ha - hydro ha

1. Gii thiu chung

Qu trnh hydro ha cng nh qu trnh hydro ha c bit t rt lu, c ng

dng nhiu trong cc qu trnh Lc - Ha du.

C th nh ngha qu trnh hydro ha, hydro ha nh sau:

Qu trnh chuyn ha m trong c s tch nguyn t H ra khi hp cht

hu c c gi l qu trnh hydro ha. Qu trnh chuyn ha m trong c s tc dng ca phn t H2c gi l

qu trnh hydro ha.

I. ng dng trong lnh vc Ha du

Trong cng nghip ha du, qu trnh hydro ha, hydro ha c ng dng tng

hp cht hot ng b mt, tng hp cc monome c gi tr nh l Butadien_1,3; styren;

formaldehyd; aceton; anilin... m ch yu l dng qu trnh hydro ha; cn qu trnh

hydro ha th c ng dng chnh trong lnh vc Lc du.

II.ng dng trong lnh vc Lc du

1. Qu trnh hydro haMt cch s b theo phm vi ng dng, c th chia qu trnh hydro ha thnh 3

qu trnh sau:

1) X l bng H2(cn gi l qu trnh hydro ha lm sch)

2) Bo ha cc hydrocacbon thm

3) Hydrocracking

1) X l bng H2

Mc ch:


27/185

2)Bo ha cc hydrocacbon thm

Mc ch:

Nng cp du nhin liu: tng ch s Cetan, gim nht, tng ch s nht...

Ci thin nguyn liu cho qu trnh Cracking xc tc: vng khng no thnh

vng no

V d:

3)Hydrocracking

Mc ch: nhm ch bin nguyn liu l cc phn on du lng bt k thnh sn

phm l kh hydrocacbon, xng, kerosen, diesel hoc nguyn liu cho sn xut

du nhndi tc dng ng thi ca nhit cao (300 - 4000C); p sut cao (50

- 200 at) v xc tc lng chc Pt, Ni../ Al2O3, zeolit.. Trong :Pt, Ni... : chc khthc hin cc phn ng hydro ha

Al2O3, zeolit... : chc acidthc hin cc phn ng cracking

V d : qu trnh hydrocracking Naphtalen

+ 2H2 + 3H2

+ 3H2CH3 CH3

Naphtalen Tetralin Decalin

ToluenToluen Metyl cyclo hexan

+ C - C - C

C - C- C + C - C - C

C


28/185

2. Qu trnh hydro ha

Trong cng ngh Lc du, qu trnh hydro ha ch yu c ng dng trong qu

trnh Reforming xc tc thu xng cha hm lng hydrocacbon thm cao, tc l xng cch s octan cao.

2. PHN LOI CC PHN NG HYDRO HA - HYDRO HA

I.Phn loi phn ng hydro ha

Phn ng hydro ha c chia lm 3 nhm:

1. Phn ng hydro ha cng hp

Lu :y l cc phn ng thun nghch

2. Phn ng hydro ha c s tch loi

y l cc phn ng c s tch loi cc phn t nh nh H2O, HCl, NH3, H2S...

CH CH+H2

CH2= CH2+H2

CH3- CH3

+H2

+H2R - C - R

O

R - CH - R

OH

R - C N+H2

R - CH2- NH2

RCOOH + 2H2 RCH2OH + H2O

ROH + H2 RH + H2O

RCONH + 2H RCH NH + H O


29/185

II. Phn loi phn ng hydro ha

1. Phn ng hydro ha khng c s thay i v tr cc nguyn t khc H

a) Phn ng hydro ti lin kt C - C

b) Phn ng hydro ti lin kt C - O

- Ru bc 1:

- Ru bc 2:

c) Phn ng hydro ti lin kt C - N

(amin) (nitril)

2. Phn ng hydro c s thay i v tr cc nguyn t khc Ha) Phn ng hydro ng vng

y l loi phn ng thu nhn hydrocacbon thm, xy ra ch yu trong qu trnh

reforming xc tc sn xut xng c ch s octan cao.

b) Phn ng hydro ngng t

y l cc phn ng to cc hp cht a vng cao phn t v cng chnh l

phn ng gy to cc, cn trong sn phm ca cc qu trnh lc du.

CH3CH2CH2CH3 CH3CH2CH=CH2CH3CH2CH=CH2CH3CH2CH2CH3CH3CH2CH2CH3-H2

CH2=CH-CH=CH2-H2

C6H5-C2H5 C6H5-CH=CH2-H2

CH3CH2

CH3CRCH2NH2-2H2

RCN

CH3CH

2CH3CC6H14

-4H2

C6H6

CH3CH2

CH3CR C O-H2

RCHO

H H H

-H2R

R

O H

H

CR

R

C = O


30/185

Thc cht phn ng trn gm 2 phn ng :

+Phn ng hydro ha :

+Phn ng oxy ha :

Nguyn tc: Phn ng hydro ha l phn ng thu nhit; phn ng oxy ha lphn ng to nhit. V vy phn ng hydro oxy ha c th lm gim s thu nhit ca

qu trnh dn n lm gim s nung nng thng xuyn hn hp phn ng.

Ngoi ra cn c mt s phn ng sau:

3. C S L THUYT CC QU TRNH

1. Nhit ng hc ca cc phn ng hydro ha v hydro ha

a) Phn ng hydro ha l phn ng to nhit v phn ng hydro ha l phn

ng thu nhit. Cng mt qu trnh th phn ng hydro ha v phn ng hydro ha s c cng gi tr hiu ng nhit nhng tri du.

Hiu ng nhit ca mt s phn ng hydro ha pha kh:

Ph H0 (kJ/ l)

CH3OH HCHO + H2

CH3OH + 1/2 O2 HCHO + H2O

RCH3 + NH3 + 3/2 O2 RCN + 3 H2ORCH2NH2 + O2 RCN + 2 H2O

RCHR + 1/2 O2 RCR + H2O

OH O


31/185

6 RCN + 2 H2 RCH2NH2 134 -159

7 RCOOH + 2 H2 RCH2 OH + H2O 38 - 42

8 RNO2 + 3 H2 RNH2 + 2 H2O 439 - 472

9 RHp + H2 R1Hp + R2Hp 46 - 63

10 RHN + H2 RHp 42 - 50

11RHa + H2

RHp

42 - 46

Nhn xt:

1) i vi phn ng hydro ha cng hp: nhit sinh ra gim dn theo th t sau:

2) i vi phn ng hydro ha c tch loi (H2O): nhit sinh ra gim dn theo

th t sau:

3) i vi phn ng hydrocracking: nhit sinh ra tng i thp v khng chnh

lch nhiu

b) Cc yu t nh hng n qu trnh

Phn ln cc phn ng hydro ha v hydro ha l phn ng thun nghch.

- Phn ng hydro ha : l phn ng to nhit, gim th tch nn phn ng s xy ra

thun li nhit thp, p sut cao; thng thng ch cng ngh cho qu trnh nh

sau:

+ t = 100- 350, 4000C

+ p = 1,5 - 40 MPa

trnh dng p sut cao m vn tng mc dch chuyn cn bng ngi ta

C C > > C N > C = C > C = O

NO

OC

O

O H


32/185

V d:

trnh dng i kin chn khng m vn lm tng mc dch chuyn cn bng,

ngi ta thng pha long hn hp phn ng bng hi nc hay kh tr lm gim p sut hi

ring phn ca cc cu t tng chuyn ha.

2. Xc tc cho qu trnh :

Ngoi cc phn ng chuyn ha nhit xy ra nhit cao km theo s phn hu v

ngng t mnh, tt c cc phn ng hydro ha v hydro ha u c xc tc.

C th phn thnh 3 nhm xc tc chnh:

1)

Cc kim loi thuc nhm VIII (Fe, Co, Ni, Pt, Pd) v nhm Ib (Cu, Ag) v cchp kim ca chng.

2) Cc oxyt kim loi: MgO, ZnO, Cr2O3, Fe2O3...

3) Cc oxyt phc hay sulfid (sulfua): CuO.Cr2O3, ZnO.Cr2O3, CoO.MoO3,

NiO.WO3, WS2(y l xc tc ra i rt sm, c hot tnh cao nhng d mt

hot tnh nn hin nay t dng.

Cc xc tc ny c bit l xc tc kim loi thng c phn b trn cc cht mang

xp v b sung vo l cc cht kch ng nh l kim loi khc, oxyt khc.

3. C ch phn ng :

K hiu K: trung tm hot ng ca xc tc

- u tin khi H2v cc hydrocacbon b hp ph ln xc tc th qu trnh hp ph vt l

lm yu cc lin kt H - H, C - H v lin kt khng no ca hydrocacbon

C2H5 CH = CH2- t = 5950C

p = 0,1MPanu p = 0,01 MPa

= 40%

= 80%


33/185

- Sau s xy ra s hp ph ha hc:

* hydro ha:

* Hydro ha:

4. Tnh chn lc ca phn ng:

Cc phn ng hydro ha cng nh hydro ha nu khng khng ch i kin phn

ng s xy ra hng lot cc phn ng ni tip hay song song nhau, chng hn nh:

Do vy tnh chn lc ca phn ng rt quan trng. N ph thuc vo cc yu tsau:

Kh nng phn ng ca cc cht hu c hay cc nhm chc ring bit

V d:Khi hydro ha aryl olefin th nhnh olefin d hydro ha hn nhn thm.

Kh nng b hp ph ca cc cht hu c hay cc nhm chc ring bit trn b mtxc tc: hp ph nh ca sn phm chnh ca cc phn ng ni tip cho php tin

hnh qu trnh vi tnh chn la tt hn v hiu sut cao hn.

V d: Khi hydro ha C2H2 v ng ng th chn lc ca olefin to thnh

K CH CH3

R

+ K K CH CH2

R

+ KH

K CH CH2

R

R CH = CH2 + K

K CH2CH

2

+ H2... KK CH

2CH

3

+ KH2K + CH

3CH

3

1. RCOOH- H2O

+ H2RCHO

+ H2RCH2OH

- H2O

+ H2RCH3

2. R -C N+ H2

R-CH=NH+ H2

R-CH2 -NH2+ H2

R-CH3 + NH3

3. C6H5OH

+ H2C6H6 + H2O

+ 3H2C6H11OH


34/185

V vy cc ceton, acid cacboxylic khng no v mt vi dn xut hydrocacbon

thm s hydro ha trn b mt kim loi ch yu theo lin kt C -C vi s bo ton

cc nhm c cc.Xc tc oxyt kim loi c mng tinh th phn cc nn c kh nng hp ph c

bit i vi nhm phn cc ca cc hp cht hu c.

V vy cc aldehyt, ceton, acid cacboxylic khng no v thm... s hydro ha trn

b mt cht xc tc ch yu theo nhm chc cha O v bo ton lin kt khng

no.

Nhit :

Nhit cng tng th kh nng chuyn ha su cng ln, cng to nhiu sn

phm ph. Bi v cc phn ng ph nh cracking, hydro ngng t v mt s

phn ng khng mong mun khc thng c nng lng hot ha cao hn phnng chnh.

V d:- phn ng cracking n_C4H10: Ehh250 kJ/mol

-phn ng hydro ha n_C4H10thnh n_C4H8: Ehh168 - 184 kJ/mol

Chnh iu ny cho php nng cao tnh chn la ca phng php h nhit .

Tuy nhin nu h nhit qu thp th tc phn ng gim v nng sut thit b

gim.

Do i vi mi phn ng s c mt khong nhit ti u.

Thi gian tip xc

Nu thi gian tip xc cng tng th chuyn ha cng tng v chn lc cng

gim. V vy i vi mi phn ng khc nhau th c chuyn ha v thi gian

tip xc ti u.


35/185

4. HA HC V CNG NGH CA QU TRNH DEHYDRO HA

Trong s cc qu trnh dehydro ha, ch kho st 3 nhm c gi tr thc t cao:

1.

Qu trnh dehydro oxy ha ru:

V d: qu trnh sn xut formaldehyt t ru metanol

2.

Qu trnh dehydro ha hp cht alkyl thm:V d: qu trnh tng hp styren t etylbenzen

3. Qu trnh dehydro ha parafin v olefin:

V d: qu trnh tng hp Butadien - 1,3 v isopren

I. Qu trnh tng hp formaldehyt t ru metanol

1. Tnh cht ca Formaldehyt

iu kin thng, formaldehyt l cht kh c mi hc, l loi kh c c th lmhng nim mc mt, c tngng t= 19

oC.

D tan trong H2O hoc Metanol

2 CH3OH + O2 2 HCHO + H2 + H2O

C2H5 CH = CH2

+ H2

CH3CH2CH2CH3 CH2 = CH CH2 CH3 CH2 = CH CH= CH2- H2 - H2

CH3CHCH2CH3 CH2 = CH CH2 CH3 CH2 = CH CH= CH2- H2 - H2

CH3 CH3 CH3


36/185

lm cht xc trng, dit khun; dng lm cht p thm, cht bo qun xc thc

ng vt (do HCHO c kh nng lm ng t protit, lm cho protit khng thi

ra)Sn xut: C nhiu phng php sn xut HCHO, nhng phn ln c sn xut

t Metanol bng 2 phng php : dehydro ha ng thi vi mt phn oxy ha

v phng php oxy ha vi lng d khng kh.

2. Cng ngh sn xut

2.1. Phng php dehydro ha v oxy ha ng thi Metanol

Phn ng chnh:

CH3OH HCHO + H2 -Ho= -85,3 kJ/mol

CH3OH + 1/2 O2 HCHO + H2O -Ho= 156,3 kJ/mol

Phn ng ph:

CH3OH + 1/2 O2 HCOOH

HCOOH + 1/2 O2 CO2 + H2O

CH3OH + H2 CH4 + H2O

CO2 + H2 CO + H2O

Trong 2 phn ng chnh, c th la chn t l ca cc phn ng sao cho phn ng

tng cng l to nhit v lc trnh tht thot nhit, ngi ta dng lng nhit ny

nung nng hn hp phn ng n nhit phn ng.

Bng tnh ton ngi ta nhn thy: khi qu trnh khong 55% l oxy ha v 45%l dehydro ha th c th s dng TBP on nhit. Theo t l ny, hn hp hi khng

kh ban u cn cha khong 45% (V) Metanol nhm nm trn gii hn n ca Metanol

trong khng kh (34 7 %V)


37/185

a. Qu trnh BASF:

S cng ngh tng hp Formaldehyt theo qu trnh BASF

a. Thit b bc hi f. Thp hp th

b. My nn kh g. Thit b sn xut hi nc

c. Thit b phn ng h. Thit b lm lnh

d. Thit b lm lnh i. Thit b trao i nhit dng hi nc

e. Thit b trao i nhit

Thuyt minh: Metanol v khng kh c trn ln vi nhau trc khi a vothit b bc hi (a). Khng kh v kh tun hon t nh thp hp th (f) c a vo

ct ring l. Qu trnh pha trn th tch gia Metanol v khng kh c hnh thnh vi

s c mt ca cc kh tr (N H O CO ) sao cho vt trn gii hn n Thng thng

f

e

i

i

h

h

g

d

cb

b

a

kh thihi

nc

hi

Metanol, nc

k.kh

hi

nc

HCHO 50%m


38/185

kch thc ht nm trong mt phm vi nht nh v c t trn mt gi c c l.

Lp xc tc c t ngay trn thit b lm lnh bng nc (d). Thit b ny s sn xut

hi nc qu nhit, ng thi lm gim nhit ca hn hp hi sn phm xung cn150

oC vi p sut hi khong 0,5 MPa.

Kh sn phm tip tc i vo y ca thp hp th 4 tng (f). Ti y kh sn

phm c lm lnh v ngng t thnh dng lng. Sn phm HCHO i ra t tng u

tin c th cha ng 50% HCHO vi hm lng MeOH trung bnh l 1,3% m; 0,01%

m acid formic. Hiu sut ca qu trnh ny c th t c t 89,5 - 90,5% mol.

Mt phn kh i ra khi giai on 4 ca qu trnh cha hm lng HCHO thp

c s dng lm kh tun hon. Phn cn li c a n thit b trao i nhit (g)

sn xut hi nc (nng lng kh to ra l 1970 kJ/m3). Trc khi i n l t th

thnh phn ca kh bao gm 4,8% V CO2, 0,3% CO v 18% H2cng nh N2, H2O v

HCHO. Kh trc khi c thi ra ngoi phi c x l loi b nhng cht c hi

nh hng n mi trng.

Trong mt trng hp khc, nu khng s dng kh i ra giai on 4 ca thp

hp th tun hon th c th s dng hn hp hi c ly ra i n thit b lm

lnh ca giai on 3 hoc 4 lm hi tun hon. Lng hi ny c mc ch lm bchi H2O v MeOH, to ra t lti u gia MeOH v H2O. i vi trng hp ny th

nhit ca hi i ra khi giai on 2 l 65oC. Hiu sut ca 2 trng hp ny tng

ng nhau v ph thuc vo lu lng dng trong thp hp th.

Thi gian sng trung bnh ca lp xc tc ph thuc vo sch ca nguyn liu:

khng

kh v MeOH. S nhim c do nguyn liu khng sch lm gim hot tnh ca xc tc

ch trong vi ngy. Thi gian sng ca xc tc s gim khi tn ti nhit cao lp xc


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b. Qu trnh chuyn ha khng hon ton v thu hi Metanol bng thp chng

ct

S cng ngh tng hp Formaldehyt bng qu trnh chuyn ha khng hon ton

v thu hi MeOH bng thp chng ct

a. Thit b bc hi d. Thit b lm lnh f. Thp hp th

b. My nn kh e. Thp chng tch MeOHg. Thit b sn xut hi nc

c. Thit b phn ngh. Thit b lm lnh i. Thit b trao i nhit dng hi ncj. Thp trao i ion tch a.formic

Thuyt minh: Metanol v khng kh c a vo thit b bc hi (a); ti y xy

t h t l i h i M OH kh kh H h h i t th h khi i khi

j

f

i

e

g

d

c

ba

kh thihi

nc

hi

Metanol

h

k.kh

hi

nc

HCHO 50%m

hi

nc

h

h

h


40/185

hu nh lm ngng t ton b HCHO, H2O v MeOH c trong hn hp snphm.

y thp thu c dung dch MeOH v HCHO cha khong 42% m HCHO. Dung dch

ny c a n thp chng ct (e), mt phn c s dng lm hi lu. Sn phmnh ca thp hp th c a n thit b TN (g) dng sn xut hi nc; sau

a n l t x l trc khi thi ra mi trng.

Ti thp chng ct (e) c s dng thit b un si li bng hi nc, v y thp

thu c dung dch HCHO 50% m vi hm lng MeOH 1%m. dung dch ny c

a n thit b trung ha nhm gim lm gim chua gy ra do acid formic n mt

ga tr < 50mg/kg.

nh ca thp chng ct thu c dung dch MeOH, mt phn c hi lu, mt

phn c kt hp vi MeOH nguyn liu lm nguyn liu cho thp bc hi.

1.2. Qu trnh oxy ha MeOH thnh HCHO - Qu trnh Formox

y l qu trnh tng hp HCHO mi bng phng php oxy ha MeOH vi

lng d khng kh cng vi s c mt ca xc tc Fe ci tin - Molybden - Vanadi

oxyt [Fe2(MoO4)3- V2O5] lm vic theo c ch oxy ha - kh nhit 250 - 400oC ;

cho chuyn ha cao t 98 - 99%.

Tiu biu l qu trnh Formox c m t bng phn ng 2 giai on trong trng

thi th kh (g), bao gm s oxy ha (Kox) v s kh (Kred) xc tc.

CH3OH (g) + Kox HCHO (g) + H2O + Kred

Kred + 1/2 O2(g) Kox H = -159 kJ/molS cng ngh ca qu trnh Formox:

Thuyt minh: MeOH nguyn liu c cho vo thit b bc hi (a). Khng kh t


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sn xut hi nc thng qua thit b TN (d). Qu trnh ny s dng lng d khng

kh.

S cng ngh ca qu trnh Formox

a. Thit b bc hi f. Thp hp th HCHO

b. My nn kh g. Du ti nhit

c. Thit b phn ng h. Thit b lm lnh

d. Thit b lm lnh i. Thp trao i ion tch acid formice. Thit b trao i nhit

Sn phm kh to thnh sau khi ra khi TBP s c lm lnh xung cn 110 oC

h thit b TN ( ) th h th (f) HCHO t kh h

f

g

d

b

i

c

b

a

hi

nc

hi

Metanol

k.kh

HCHO 50%m

h

e

kh thi

nc

i i h kh khi i khi h h h kh d l


42/185

i vi qu trnh ny, kh khi i ra khi thp hp th khng c s dng lm

kh t v thnh phn ca n bao gm N2, O2v CO2vi hm lng nh cc thnh phn

d chy nh dimetyl ete, CO, MeOH v HCHO. Do vy vic t chy kh ny nhmcung cp nhit cho qu trnh sn xut hi nc khng c hiu qu kinh t.

Bng so snh cc ch tiu kinh t ng vi tng qu trnh :

Cc ch tiu Qu trnh chuyn

ha hon ton

(BASF)

Qu trnh chuyn ha

khng hon ton v

thu hi MeOH bng

chng ct

Qu trnh

Formox

Tng gi tr u t

106.USD

6,6 8,6 9,6

Tiu hao nguyn liu MeOH

(tnh cho 1 kg HCHO)

1,24 1,22 1,15

Gi sn phm USD/t 345 364 339

II.Qu trnh tng hp Styren: C6H5-CH=CH21. Tnh cht ca Styren

iu kin thng, styren l mt cht lng khng mu c ts= 145oC 0,1MPa;

d420

=0,907

ng dng:

o

Styren d polyme ha khi nung nng hay di nh hng ca cc cht

khi u v to ra polyme rn: polystyren

H h t b St t b h h d h d h


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o Hu nh ton b Styren c sn xut bng phng php dehydro ha

etylbenzen

C6H5 CH2CH3 C6H5 CH = CH2 + H2

o 2 phng php mi ang nghin cu:

kt hp oxy ha benzen vi etylen xc tc bng Pd

C6H6 + C2H4 + 1/2 O2 C6H5 CH = CH2 + H2O

ngng t oxy ha toluen thnh Stylben, sau stylben phn hu

cng vi etylen to ra styren

C6H5 CH3 + O2 C6H5 CH = CH C6H5 + H2O

C6H5 CH = CH C6H5 + C2H4 2 C6H5 CH = CH2

2. Ch cng ngh dehydro ha etylbenzen tng hp styren

C 2 ch cng ngh:

Cng ngh khng c xc tc:

o Nhit phn ng t = 700 - 800oC

o

chuyn ha C% = 20 - 30%

o

Hiu sut sn phm : 50 - 60%

Cng ngh c xc tc:

o Nhit phn ng: tu thuc loi xc tc s dng, tuy nhin t 600oC

o

Ap sut ring phn ca hydrocacbon : thp (nh s pha long bng hi

nc)o

chuyn ha cao hn, chn lc cao (khong 90%), tuy nhin c xut

hin phn ng cracking v hnh thnh ti Cacbon.

Ngoi ra cn mt vi oxyt ph Cht xc tc lm vic lin tc t 1 2


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Ngoi ra cn mt vi oxyt ph. Cht xc tc lm vic lin tc t 1 - 2

thng, sau mi ti sinh n bng cch t chy lp than cc bng

khng kh. Thng tui th ca xc tc t 1 - 2 nm.Ch : qu trnh dehydro ha etylbenzen tng hp styren thng khng ch

chuyn ha khng cao, v sn phm d b polyme ha.

3. S cng ngh: tu thuc phng thc lm vic ca TBP, c 2 dng qu

trnh cng ngh chnh:

Qu trnh on nhit

Qu trnh ng nhit

3.1. Qu trnh dehydro ha on nhit

c im: nguyn liu phi c gia nhit khong 650oC (v chnh iu ny

dn n phn ng cracking th cp) sau c a n TBP c cha cc tng

xc tc. Nng lng b sung cho nguyn liu s c thc hin nh hi nc.

iu kin vn hnh:

o

Nhit vo TBP = 650oC ; nhit ra = 580oC

o Ap sut : khong 1,4 - 2 bars

720oC 520

oC

650oC

580oCl ng

hi nc

hi ncetylbenzen

styren th

i x l kh

TBP

Trc khi vo TBP etylbenzen c trn vi 90% hi nc cn li c nhit


45/185

Trc khi vo TBP, etylbenzen c trn vi 90% hi nc cn li c nhit

720oC v khi s nng nhit nguyn liu ln 650oC. TBP c ch to bng thp

Crm (nu c s c mt ca Ni s dn n cc phn ng th cp).Nng sut cc i ca loi thit b ny t t 15000 - 17000 tn / nm.

Dng sn phm ra khi TBP c t = 580oC sau khi TN vi nguyn liu v

c ngng t mt phn s c a i phn tch. T phn nh ngi ta s thu c

hn hp kh thi c cha khong 90% H2v 10% CO2. Phn nng gm c benzen v cc

hydrocacbon nng khc.

3.2. Qu trnh dehydro ha ng nhit

Tiu biu c qu trnh BASF.

c im: thit b phn ng ng chm c hng= 2,5 - 4 m; ng= 10 - 20 cm v

xc tc c cha y trong ng

styren th

nhin liu

ng dn khi l qut gi

khi

375oC

630

o

C

TBP

750oC

580oC

580oC

l

hi nc

etylbenzen

i x l kh

Ch vn hnh ny c th thay i ty thuc vo bn cht cht ti nhit v


46/185

Ch vn hnh ny c th thay i ty thuc vo bn cht cht ti nhit v

h thng thu hi nhit.

Thuyt minh dy chuyn BASF: trong s BASF, cht ti nhit c s dngl khi l. Etylbenzen v hi nc c cho bay hi v lm nng qu nhit nh qu

trnh TN vi dng sn phm ra khi TBP. Khi l sau khi TN s h nhit xung

cn 375oC, mt phn c thi ra, v phn cn li c gia nhit trong l tip tc lm

cht ti nhit.

Nng sut cc i ca qu trnh ny khong 22000 tn/ nm.

* Qu trnh on nhit SX Styren 2 thit b phn ng:

3.3. Tinh ch Styren th

Styren th thu c bao gm etylbenzen cha chuyn ha, nc, styren v cc

Tch loi Benzen, Toluen v H2O. Benzen c th c tch ring v thu hi cho


47/185

Tch loi Benzen, Toluen v H2O. Benzen c th c tch ring v thu hi cho

qu trnh alkyl ha

Thu hi etylbenzen v hi luTinh ch Styren khi b nng (c th t tinh khit 99,8%)

Cc giai on ny phi thc hin p sut chn khng duy tr nhit thp

(n mc c th) nhm trnh s polyme ha Styren. ng thi trnh hin tng ny

ngi ta c s dng cht c ch:

Lu hunh hoc dinitrophenol cho 2 giai on u

p.tert -butylpyrocatchol cho giai on cui v giai on tn cha.

III. Qu trnh tng hp Butadien-1,3 v Isopren

1. Tnh cht Butadien-1,3 v Isopren

1.1. Tnh cht Butadien-1,3

iu kin thng l cht kh khng mu, c mi nh, c ts= -4,3oC

t ha tan trong nc v tan rt t trong metanol, etanol nhng li tan nhiu trong

cc dung mi hu c nh dietyl ete, benzen, CCl4.

To hn hp n vi khng kh trong khong nng 2,0 - 11,5% (V)

C c tnh ph hu mng nhy hay gy tc dng ph

ng dng: l monome c s tng hp cao su

o Polyme ha tng hp cao su Butadien

n CH2= CH - CH = CH2 [- CH2- CH = CH - CH2-]n

o Copolyme ha vi Styren, Acrylonitril tng hp nha ABS

Sn xut : c 3 phng php hin nay ang s dng

o Tch Butadien 1 3 t phn on C ca sn phm nhit phn phn on


48/185

o Dehydro ha n-butan tch ra t cc kh thi

1.2. Tnh cht Isopren

Isopren l n v cu trc c s ca cao su t nhin.

iu kin thng l cht lng khng mu d bay hi c ts= 34oC

Tan hn ch trong nc: 20oC ha tan c 0,029% mol trong nc; tuy nhin

n c th trn ln trong dung mi hu c vi mi t l, chng hn nh etanol,

dietyl ete, aceton, benzen.

To hn hp n vi khng kh trong khong nng 1,7 - 11,5% (V)

ng dng:

o

Polyme ha vi xc tc c kim sn xut cao su polyisopren

n CH2= C - CH = CH2 [- CH2- C = CH - CH2-]n

CH3 CH3

o

Copolyme ha vi styren sn xut cao su Isopren - Styren

Sn xut: sn xut isopren cng dng 3 phng php nh trng hp

Butadien-1,3; tuy nhin do s phc tp v thnh phn dn n kh khn ln cho

vic phn tch cc phn on ban u hay thu nhn c lm nh hng n gi

tr ca phng php tng hp isopren. Ngoi ra cn c 2 phng php khc:

o

i t Isobuten v formaldehyt HCHO (xem thm sch Ptrochimie): 2 giaion

C4H10 C4H8 C4H6- H2 - H2

(CH3)2- C = CH2 + 2 HCHO C

CH3 CH2- CH2

O


49/185

Isome ha

Cracking

2. Cng ngh dehydro ha sn xut Butadien-1,3 v Isopren

2.1. Cng ngh dehydro ha phn on olefin sn xut dien

Xc tc : cht xc tc tt nht hin nay l photphatcanxiniken Ca8Ni(PO4)5kt

hp thm cht ph gia tng hot Cr2O3(khong 2%). c im ca loi xc tc

ny l b than ha nhanh v mt hot tnh, v vy phi thng xuyn loi tr than

cc. Do cn phi c nhiu TBP lm vic song song nhau, thc hin lin tccc bc dehydro ha v ti sinh xc tc. V d nh cng ngh Dow B, 1 chu

k gm 30 pht: 15 pht thc hin phn ng, ti sinh xc tc 11 pht, thi khng

kh pha long vi hi nc trc v sau khi ti sinh mi lt 2 pht.

C pha long bng hi nc gim p sut ring phn v gim hnh thnh

cc thng theo t l 20 : 1

VVH = 150 - 200 h-1

Ap sut tng vt qu cht t so vi p sut kh quyn

Nhit ti u dehydro ha buten 600 - 650oC ; %C = 40 - 50%; %S (sn

phm) = 85%. i vi isopenten c kh nng phn ng mnh hn, v cho phnng ph nhiu hn th nhit ti u gim xung 550 - 600oC ; %C = 40% ; %S

= 82 = 84%

CH2= C - CH2- CH2- CH3

CH3

CH3- C = CH - CH2- CH3

CH3

CH3- C = CH - CH2- CH3

CH3

CH2= C - CH = CH2 + CH4

CH3

on dehydro ha v ti sinh nn TBP (4) lm vic theo tng cp; nu 1 thit b


50/185

ang dehydro ha olefin th thit b kia s ti sinh xc tc bng hn hp khng

kh vi nc. Sau mi giai on ny, cc thit b c ra tc thi bng hi nc

v thi khng kh. Nhit ca cc kh ti sinh v phn ng c dng to hi.

Sau cc kh ti sinh s c thi ra ngoi cn kh phn ng th em i phn

tch.

S cng ngh dehydro ha olefin

1,2. L t ng 6. Thit b lc kh

3. Thit b trn 7. Thit b lnh

4. Thit b phn ng 8. Thit b thu hi hi

5. Thit bto hi

u tin tch c hydrocacbon thp v cao phn t (bng cch chng phn on

p sut d nh) v t phn on C4hay C5s tch c tng ng l Butadien hay

4 4

7

nc

6

5 5

88

sn phm

kh thi

nc

hi

3 3

khng kh

olefin

1

hinc

2

hi

nc

hi

chuyn ha v tnh chn lc ca qu trnh dehydro ha n-olefin thnh dien c


51/185

th c ci tin bng vic loi b H hnh thnh trong qu trnh phn ng v b sung O 2

vo chuyn ha lng H ny thnh H2O.

CH2= CH - CH2- CH3 + 1/2 O2 CH2= CH - CH = CH2 + H2O

Bng phng php ny s loi tr tnh thun nghch ca phn ng dehydro ha v

lm gim s hn ch v mt nhit ng hc ln chuyn ha ca olefin, cn qu trnh

th t on nhit chuyn thnh to nhit to iu kin thun li hn tin hnh cng

nghip. Ngoi ra cng nh cc phnng oxy ha khc s lm gim mnh cc hin tng

khng mong mun nh cc ha v cht xc tc c th lm vic trong thi gian di m

khng cn phi ti sinh.

Cc iu kin cng ngh:

o

Xc tc: cht xc tc cho qu trnh dehydro oxy ha l hn hp cc oxyt ca Bi +Mo; Bi + Mo + P; Bi + W; Sb + Fe ...

o

Nhit : 400 - 600oC

o T l hi nc pha long: t 1:5 n 30:1 (V)

o

chuyn ha: 70 - 80%

o chn lc: i vi Butadien-1,3 : 90 - 95%

i vi Isopren: khong 85%

o TBP: qu trnh dehydro ha v oxy ha c tin hnh ng thi trong mt

thit b vi lp xc tc c nh

o

C ch: c ch oxy ha kh vi s tham gia ca O2vo mng li tinh th oxytkim loi

K - O - + C4H8 K - O - C4H8 K + H2O + C4H6

Sau kh c lm lnh bng nc thit b lc kh (4) cng vi thit b lm


52/185

lnh (5) v ra bng dch khong thit b hp th(6). Ti y s hp th hydrocacbon

C4cn cc sn phm cracking, N2v phn d O2 s thot ra khi nh ca (6) v s

dng lm nhin liu kh trong l t ng (1).

Cht lng bo ha t thit b (6) s cho qua thp tch hi (8) ti sinh dung mi hp

th v a tr v (6) sau khi thit b lm lnh (7). Phn on C 4 pha trn (8) cha

khong 70% Butadien-1,3. Bng cc phng php bit s tch c Butadien-1,3

tinh khit; cn n-buten cha chuyn ha s hon lu v qu trnh dehydro oxy ha.

S qu trnh dehydro oxy ha n-buten:

S cng ngh dehydro oxy ha n-buten thnh butadien-1,3

1. L t ng 6. Thit b hp th

2. TBP 8. Thp tch hi

3. Thit b to hi 9. Thit b ngng t hon lu

10

9

7

du h.th

n-buten

2

3

4

5

6

8

nc

hi

kh t

khng kh

hi nc

nc

C4

1

CHNG III: QU TRNH HALOGEN HA


53/185

1. NHNG C TRNG CHUNG CA CNG NGH HALOGEN HA

I. Gii thiu:Qu trnh halogen ha l mt trong nhng qu trnh quan trng trong tng hp

hu c, gm c: qu trnh Clo ha, Brom ha, Flo ha, Iot ha; trong :

+ ng dng trong cng nghip ch yu l qu trnh Clo ha, Flo ha

+ qu trnh Brom ha, Iot ha: thng dng trong phng th nghim, vin nghin

cu, sn xut nh...

Tm quan trng ca qu trnh Halogen ha:

- to ra cc monome cha halogen (X):

+ VCM: vinylclorua monomel monome quan trng tng hp nha PVC

+ tetra flo etylen: tng hp nha polytetrafloetylen l loi nha c th chu

c tt c cc mi trng nh lin kt C F, chu nhit v khng kt dnh

- sn xut dung mi c ha tan cao: CCl4; CHCl2- CCl3; CH2Cl2.

- sn xut cc hp cht trung gian nh:

+ DCE: dicloetanphn ln dng sn xut VCM

+ Cloruabenzen l tc nhn alkyl ha sn xut cc hp cht cha Oxy nhru, phenol...

- sn xut cc tc nhn lnh: freon (dn xut clo - flo) nh F1,2(CF2Cl2);

F2,2 (CHF2Cl)

(+ s u tin t phi sang: s nguyn t flo

+ s th hai:= s nguyn t H + 1

+ s th ba: = s nguyn t C - 1

+ s nguyn t Clo: cn li)

-phn ng ct mch


54/185

Nhng tc nhn halogen ha thng dng nht l halogen t do v hydrohalogen

khan nc. Nhit si ca chng iu kin thng nh sau:

F2 -188,0oC HF 19,4

oC

Cl2 -34,6oC HCl -83,7

oC

Br2 58,8oC HBr -67,0

oC

I2 +185oC HI -35,36

oC

1. Halogen ha th:dng th nguyn t H hoc gc OH bng 1 nguyn t X hocth nguyn t X ny bng mt nguyn t X khc.

1.1. Th bng X2:

RH + X2 RX + HX

Trong trng hp ny nguyn t X c th gn ln nguyn t C no, khng no hoc vng

thm v kh nng phn ng nh sau:

I2 < Br2 < Cl2 < F2

Vi I2 : phn ng xy ra chm, thun nghch

Br2 : phn ng xy ra mnh hn, thng dng trong phng th nghim

Cl2 : phn ngxy ra mnh, ng dng nhiu trong cng nghipF2 : phn ng xy ra rt mnh lit, d n ct mch Cacbon

* Hiu ng nhit ca cc phn ng

RCH3 + X2 RC H2X + HX

X2 - H2980(KJ/mol)

F2 460

Cl2 105

Br2 34

Phn ngny c xem nh l phn ng este ha gia acid v alcol to thnh


55/185

halogenua v H2O

Kh nng phn ng ca cc HX nh sau: HF < HCl < HBr < HI

- Th halogen bng Halogen

ng dng iu ch cc dn xut F, Br, I t nhng hp cht cha Cl

CCl4 + 2HF CCl2F2 + 2HCl

RCl + NaBr RBr + NaCl

- Th cc hp cht aminoC th thc hin phn ng th mt nhm chc amino bc 1 ca hydrocacbon

thm bng mt nguyn t X to thnh hp cht trung gian diazohalogenua. Sau

phn hy hp cht ny to halogenua thm v N2:

V d:

ArNH2 + NaNO2 + 2HX ArN2X + NaX + 2H2O

ArN2X ArX + N2

2. Halogen ha cng hp: l phn ng cng X2, HX hay cc Halogenua vo ni i

hoc ni ba.

2.1. Cng hp vo ni i: cc tc nhn nh X2, HX, acid hypocloric HClO c th

tham gia phn ng cng vo cc ni i c th to thnh cc hp cht mono hoc

dihalogen

- Cng X2:

Phn ng : RCH = CHR' + X2 RCH - CHR'

X X

* Tt c cc X2u c th tham gia phn ng ny:

+ vi Cl2, Br2, I2: phn ng xy ra vi s c mt ca xc tc Halogenua kim loi

0


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Hiu ng nhit - H2980(KJ/mol)

Phn ngCH

2= CH

2+ X

2 CH

2= CH

2 CH

2= CH

2+ HX CH

3- CH

2

X X X X

III.F 540 42

Cl 184 71

Br 92 88

I 17 88

- Cng HClO:

Hp cht HClO c to thnh bng cch sc Clo vo H2O sau cho phn ng

vi olefin to Clohydrin.

RCH = CHR' + HClO RCH - CHR'

OH Cl

Clohydrin

2.2. Cng vo ni

Cc X2v HX c th cng vo ni to thnh cc olefin c cha halogen. V

cc olefin ny c th tip tc b halogen ha to thnh hp cht polyhalogen.

- Cng vi X2:

R - CC - R' + X2 R - C = C - R'

X X

R - C = C - R' + X2 R - CX - CX - R'

X X X X

- Cng vi HX:

R - C C - R' + HX R - C = C - R'

3. Phn ng ct mch ca nhng dn xut Clo

M h i bi


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Mt s phn ng tiu biu:

CH2Cl - CH2Cl CH2= CHCl + HCl (1)

CCl3- CCl3 CCl2= CCl2 + Cl2 (2)

CCl3- CCl3 + Cl2 2CCl4 (3)

CCl3- CCl2- CCl3 CCl4 + CCl2= CCl2 (4)

Phn ng (1): phn ng dehydrocloric ha phn ng ny xy ra kh d dng, ngc

li vi s kt hp hydrocloric (HCl)Phn ng (2): phn ng declo ha phn ng ny xy ra nhit cao hn

Phn ng (3): phn ng nhit phn clo phn ng ct mch C - C di tc dng ca

Cl2

Phn ng (4): phn ng nhit phnxy ra nhit kh cao

III. Cng ngh halogen ha v thit b phn ng

Qu trnh halogen ha c th tin hnh :

-pha lng hoc pha kh

- gin on hay lin tc

- theo c ch chui gc hoc c ch cation1. Cng ngh pha lng

- Nguyn tc: sc X2 (thng dng nht l Cl2) vo pha lng, pha lng c th l

hydrocacbon (tc nhn phn ng) hay dung mi (trong trng hp tc nhn phn ng

th kh); khi phn ng s xy ra trn b mt phn chia kh - lng (tc trong khi cht

lng). Nu nh ngoi sn phm lng cn c to thnh HCl, kh ny phi c dn ra

bng mt h thng ring cng vi Cl2cha phn ng.

- c im:

+ khi tng nhit th tc phn ng tng ln v khi cc phn ng ph s

hi h


58/185

xy ra nhiu hn.

- Thit b phn ng : c 2 loi theo ch lm vic

* Thit b lm vic gin on:

(a) (b) (c)

- loi (a), (b): thit b loi thng, c cnh khuy,c v o lm lnh, c ng xon

- loi (c): c h thng lm lnh ngoi, c bm tun hon thay cho c cu khuy

+ Thit b lm vic lin tc

(a) (b)

HCl

RH

HCl

RH

sn phm

Cl2

HClRH

sn phm

Cl2

HClRH

H2O

sn phm

Cl2

HClRH

- loi (b): thit b lm vic lin tc vi s lm lnh ngc dng

2 Cng ngh pha kh:


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2. Cng ngh pha kh:

Khi tin hnh trong pha kh th nhit qu trnh cao nn xy ra nhiu phn ng

ph, do sn phm to thnh l mt hn hp phc tp. Hn hp ny thng c cho

qua thit b ngng t, sau i phn ring thnh cc hp cht khc nhau theo cc

phng php thng thng.

Mt s thit b phn ng :

- thit b ng chm: vi lp xc tc c nh t trong ng- thit b nhit: (hnh a)

Loi ny khng dng xc tc m dng nhit khi mo phn ng vi nhit

phn ng khong 300 400oC. Do thit b phi c lt gch chu la.

c im ca loi ny l do ng nng gia 2 dng kh s to nn s khuy trn

dn n c s ng u v nng , nhit .

- thit b lp si: (hnh b)

Loi ny c tun hon cht rn, cht rn ny c th l cht mang nhit hoc l xc

tc.

lp m

ginhit

phn ngRH

Cl2

sn phm

sn phm

ht rn

i xung

mng nhy trong mt, gy ngt th nh phosgne COCl2; n mn da v m xng nh

F2 v HF T nhng l do trn thit b phn ng phi t cc yu cu sau:


60/185

F2v HF. T nhng l do trn thit bphn ng phi t cc yu cu sau:

+ c kn kht cao

+ cc phn xng sn xut phi c qut thng gi

+ ti ni lm vic phi c cc thit b s cu v c mt n phng c.

- Tc nhn phn ng v sn phm gy n mn ln i vi thit b phn ng cng nh

ng dn, b cha. V cc halogen c th tc dng vi kim loi ch to thit b to

thnh cc halogenua kim loi lm xc tc cho cc phn ng ph. V vy khi tnh tonthit k mt thit b halogen ha th vic chn vt liu lm thit b l ht scquan trng

v n ph thuc vo tng trng hp c th:

+ c th dng vt liu bng thp c trng men hoc lt gm s hoc ph kim

loi c bit c kh nng chng n mn.

+ c th dng vt liu c bit nh grafit, thy tinh...

Chng hn: Khi tin hnh qu trnh Flo ha th dng vt liu l Ni hoc Cu.

Khi tin hnh qu trnh Clo ha th dng thp c ph bng vt

liu ch, men hoc gm s

- Qu trnh halogen ha th vi tc nhn phn ng l HX hoc trong qu trnh phn ng

to kh HX, khi c mt canc s to ra cc dung dch acid HX gy n mn rt nhanh.

Do cn phi sy kh nguyn liu trc khi a vo thit b phn ng.

4. Chun b cht phn ng v x l hn hp kh sn phm

4.1. Chun b cht phn ng

- ha hi Clo lng- tch m: hi Closy bng H2SO4; cht phn ng hu c tch m bng chng ct ng

ph hoc hp ph rn

+ i vi phn ng cng hp: lng HCl t nn ngi ta ra kh bng nc v

thi vo h thng thi


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thi vo h thng thi

+ i vi phn ng th: lng HCl thu c ln, cn c hp th bng nc s

thu c HCl 20 - 30%. Kh cn li c th loi b.

- X l sn phm lng ngng t: sn phm lng sau khi tch kh vn cn cha m t

lng HCl cn lm sch v sau phn ring sn phm

+ Lm sch HCl: c nhiu phng php theo cc thit b phn ng sau

(a) (b) (c)

- loi (a): i vi trng hp dn xut halogen thu c c bay hi thp (nh clorua

parafin, clorua benzen...) th tch HCl bng cch thi khng kh hoc N2.

- loi (b): i vi trng hp cn tch k HCl: ra bng H 2O ra bng dung dch

kimra li mt ln na bng H2O.Nhc: to ra mt lng nc thi ln

- loi (c): hin i, tch HClv lng RH d bng chng ct c hi lu

RH

RCl

HCl

RH

RClHCl

RH, RCl

khng kh

hoc N2

khng kh, HCl

sn phmRH, RCl,

NaOH

RH, RCl

H2O

RCl

HCl

RH

Dd HCl thi

2. CC QU TRNH CLO HA

Thng chia lm 2 loi: - clo ha cc hydrocacbon mch thng (khng vng)


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Thng chia lm 2 loi: - clo ha cc hydrocacbon mch thng (khng vng)

- clo ha cc hydrocacbon thm

I. CLO HA CC HYDROCACBON MCH THNG

- Mc ch: ch yu sn xut cc hp cht trung gian monome trong cng nghip sn

xut cc sn phm nh nha, dung mi, thuc tr su, cht ti nhit... t cc ngun

nguyn liu: CH4, C2H6, C3H8, C2H4, C2H2... m cc hydrocacbon ny c th thu nhn t

nhiu ngun khc nhau: kh t nhin, kh ng hnh, kh ca cc qu trnh ch bin thcp nh FCC, RC...

- Chia lm 2 qu trnh : + Clo ha parafin

+ clo ha olefin

1. CLO HA PARAFIN

1.1. c im

- qu trnh clo ha parafin c thc hin theo phn ng thvi c ch gc t do

- trong cng nghip: CH4, C2H6, C3H8... c s dng nhiu nht, qu trnh thng c

tin hnh trong pha kh v cc nhit khc nhau ca cht tham gia phn ng, khng

c s ct mch C - C.

- i vi cc parafin nng hn, thng dng cc phn on C10- C13, C14- C17, C20-

C38... c tin hnh trong pha lng, nhit thp 80 - 100oC (nhit tng s lm

cho sn phm c mu) v c th xy ra s ct mch C - C, trong trng hp gi l

qu trnh Clorolyse.

- qu trnh clo ha cc parafin l qu trnh to nhit mnh nhng lng nhit to ra nhhn qu trnh flo ha v ln hn qu trnh brom ha. Qu trnh Iot ha l qu trnh thu

nhit.

- i vi nhng qu trnh xy ra vi vn tc ln s d gy ct mch C -C; khc phc

ngi ta thng dng cc bin php sau:


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g g g p p

cho tha parafin

pha long parafin trong mt dung mi thch hp

pha long Cl2bng mt kh tr

tin hnh phn ng vi nhit thp.

1.2. C ch qu trnh : qu trnh xy ra theo c ch gc qua cc giai on sau

- Giai on khi mo: l giai on to gc t do, bng 3 cch: + dng nhit:y l qu trnh clo ha nhit,v thng dng cho qu trnh pha

kh

Khi Cl2di tc dng ca nhit s phn hu to ra gc t do Cl*

+ dng nh sng:y l qu trnh clo quang ha

iu kin l nh sng phi nng lng t lin kt Cl - Cl, thng thng ngi

ta chiu bng tia cc tm.

+ dng cht khi mo:yl qu trnh clo ha ha hc

iu kin l cht khi mo phi c kh nng b phn hu thnh gc t do nhit

va phi, thng thng ngi ta dng peroxit benzoil hoc 2,2 - azo bisizobutyronitril.

Cl2 Cl

*

+ Clhp ph

nhit thnh

(thit b, m nng)

Cl2 + h Cl* + Cl

*

(C6H5COO)2 2C6H5COO* 2 C6H5

* + 2CO280100

oC

- Giai on t chui


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+ pha kh: s t chui ch yu xy ra do va chm vi thnh thit b

hin tng t chui bc 1

+ pha lng: t chui bng cch kt hp cc gc hin tng t chui bc 2

C ch t chui ph thuc vo: + bn lin kt

+ mt ca cc gc

+ kh nng hot ng ca cc gc

Ch :Khi nghin cu qu trnh Clo ha cc hydrocacbon khc nhau cc iu

kin khc nhau th kh nng Clo ha nh sau:

- nhit thp hoc va th kh nng Clo ha c sp xp:

C1 < C2 < C3

- nhit cao th kh nng th ca Cl vo cc nguyn t C tin n tng ng

nhau

- bn nhit ca cc hydrocacbon cha Cl thay i theo dy sau:

C1

> C2

> C3

- khi trong phn t cha nguyn t Cl th kh nng tip tc th ca nguyn t

Cl vo phn t s xy ra km v km nht ti v tr C k cn nguyn t C cha

Cl* + thnh Clhp ph

RCH2CH2* + RCH2CH2

* R(CH2)4R RCH= CH2 + RCH2CH3

Cl* + Cl

* Cl2

R* + Cl

* RCl

ng dng ca cc sn phm cloruametan:

+ CH3Cl: iu kin thng l cht kh khng mu c tnt= -23,70C, tan trong nc v


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mt s dung mi nh benzen, acid acetic, etanol...

- 60 - 80% dng sn xut Silicon

- 10 - 15% dng sn xut metyl cellulose: hp cht ny c c tnh trng n

trong nc to dung dch keong dng trong sn, h vi si, ...

- cn li: lm tc nhn metyl ha

- trc y c dng sn xut TML (tetra metyl ch)

+ CH2Cl2: iu kin thng l mt cht lng khng mu, c bay hi cao, si

40,2oC, c ha tan rt cao nn ch yu c dng lm dung mi nh dung mi ty

sn, dung mi trch ly...

+ CHCl3:iu kin thng l mt cht lng khng mu, si 61,3oC; c mi c

trng; hi ca CHCl3khng to hn hp n vi khng kh; ho tan tt trong ru v ete

v c th trn ln vi mt s dung mi hu c.

- dng sn xut monome cho nha polytetra flo etylen hay cn gi l Teflon

- trc y dng sn xut freon

CHCl3 CHClF2 CF2= CF2

CHCl3 + 2HF CHClF2 + 2HCl

F2,2

xt: SbCl5

CH3 CH3 CH3

...- O - Si - O - Si - O - Si - O -...

CH3 CH3 CH3

2CH3Cl + Si (CH3)2SiCl2 n (CH3)2Si(OH)2

Tu theo s khng ch iu kin k thut ca qu trnh m thu c cc sn

phm mong mun khc nhau, mono hay di hay tri hay tetracloruametan.


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Cn phi ch rng khng nn tin hnh phn ng clo ha nhit cao hn

550oC v s xy ra phn ng n:

CH4 + 2Cl2C + 4HCl + 69,7Kcal

Di y l thnh phn sn phm thu c khi clo ha metan ph thuc vo iu

kin qu trnh

Nhit Cl2: CH4 Thnh phn sn phm (%)CH3Cl CH2Cl2 CHCl3 CCl4

440 1 : 2 62 30 7 1

440 1,1 : 1 37 41 9 3

440

440

440

440

440

460

1,68 : 1

1,98 : 1

2,28 : 1

3,02 : 1

3,31 : 1

3,88 : 1

19

11

5

3

-

-

43

35

29

15

6

-

33

45

52

53

43

4

4

9

14

29

51

96

Cng ngh clo ha Metan thc hin pha kh gm cc giai on sau:

- Chun b cht phn ng ban u

- Clo ha

- X l kh thot ra v tn dng HCl- X l v tch sn phm

a. Chun b cht phn ng ban u

1

Sn phm


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1. thn thp bng thp

2. gch samt chu nhit

3. m s

4. ng phn ng bng gm

V ca thit b bng thp, trong lt gch samot. Metan v Clo khan c dn vo

gia thit b theo ng lm bng gch chu la. u tin t nng Metan bng khng

kh un nng thit b sau thay dn khng kh bng Cl2. Phn trn ca thit b ct lp m kh Cl2phn ng c hon ton.

Qu trnh thng thc hin nhit 400 - 450oC vi s d CH4, thu c ch

yu l CH3Cl, CH2Cl2. Mun thu c CHCl3, CCl4th cho sang thit b phn ng tip

theo v thm kh Cl2vo.

c. X l kh phn ng

Hn hp kh sn phm thu c thng dng H2O hp th kh HCl hoc dng

dung dch HCl nng thp hoc dng dung dch NaOH trung ha ty thuc vo

nng ca kh HCl hoc c th kt hp c 3 cch trn.

Sau dng my nn, nn kh sn phm n 25 - 100 atm. Lng CH4d cngnhiu th nn n p sut cng cao. Cui cngl sy v tch phn kh hon lu v chng

ct sn phm lng.

Cl2

CH4

1

2

3

4

CH3ClCH2Cl2

CHCl3


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S Clo ha CH4bng phng php Hoechst (sn xut CH2Cl2vCHCl3)

a. thit b phn ng e. my nn

b. thit b lm lnh bng khng kh f. thit b lm ngui bng nc

c. thp hp th kh HCl g. h thng lm kh kh

d. h thng trung ha

h. h thng ngng t th cp v cha sn phm th

i. cc thp chng ct thu hi CH3Cl, CH2Cl2, CHCl3, CCl4.

Thuyt minh:Kh CH4sch v hn hp (CH4/CH3Cl) hi lu cng vi kh Cl2sch a

vo thit b phn ng (a). Trong ng thit b phn ng c ph mt lp Ni, phn ng xy

ra iu kin on nhit. Nhit cn thit cho phn ng l 350 - 4500C. Hn hp kh

phn ng i ra nh c lm ngui nh thit b lm lnh bng khng kh (b). Sau c a sang thit b hp th kh HCl (c) vi dung dch HCl c nng thp khong

20%. Hn hp kh sn phm tip tc i qua h thng trung ha (d) bng dung dch

e

Cl2

CH4

f

b

2 2 CHCl3

CCl4

i i i

h

dcca g

HCl 31% HCl 20% NaOH

d. S qu trnh Hoechst sn xut CCl4

S cng ngh gm 6 thit b phn ng ni tip nhau. Nguyn tc ca phng


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php l nguyn liu cho vo thp th nht cn kh Cl2c cho vo tng thit b phn

ng.

S sn xut CCl4bng qu trnh Clo ha CH4(Hoechst)

a. h 6 thit b phn ng e. B cha sn phm th

lng

hi

nc

CCl4

HCl

Phn nh

(CH3Cl)

CH4

Cl2

H2O

H2O

HClcbbb

aa

ad

lm n

o

kh thi ilm sch

fe

g

h ij

Phn nng

Nguyn liu vi lng d CH4(v CH3Cl hi lu) v mt phn Cl2vo thit b

phn ng th nht, ton b lng Clo s chuyn ha 400oC. Hn hp kh sn phm


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thit b th nht c lm lnh v a vo thit b phn ng th hai c b sung lng

Cl2cn thit. S thm Cl2tng bc vi s lm lnh gin on n thit b phn ng cui

cng vi t l CH4 : Cl2= 1:4. Hn hp kh i ra s c lm lnh 2 bc n -20oC.

Phn lng thu c ch yu l CCl4c a v b cha snphm th (e). Hn hp kh

c cha HCl a sang thit b hp th on nhit (l) bng H 2O hoc bng dung dch HCl

20%, y thu c HCl 31%. Hi ly ra nh s c ngng t thit b (m) bngdng lu cht lnh. a s CH3Cl thot ra thit b lm lnh v phn tch pha (n). Nc

ra (m) c lm sch trc khi loi b. Kh thi lm sch trc khi thi ra mi

trng.

Lng thu c a v thng cha sn phm th cn cha thnh phn kh t do

CH3Cl, Cl2, HCl c a sang thit b tch nc (f), cc vt nc thu hi bng chngct v a v thit b hp th HCl. Sn phm tip tc a sang thp tch sn phm nh

(h); nh thu c sn phm nh hi lu v thit b phn ng , phn lng y (h)

c a sang thit b lm sch v tch sn phm CCl4 thit b (i) v (j). Cn cui

cng vi thnh phn cha 2 - 3% m CCl4dng sn xut hexacloetan, tetracloetylen,

tricloetylen.

1.4. Qu trnh clo ha etan

1.4.1. Sn phm ca qu trnh clo ha etan:sn phm ng dng chnh l C2H5Cl

Tnh cht ca Clorua etan: iu kin thng, l cht kh khng mu, ha lng 12,2 oC, tan t trong

nc.

S cng ngh qu trnh Shell:

Qu trnh thc hin theo phn ng sau:


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CH3- CH3 + Cl2 CH3CH2Cl + HCl

CH2= CH2 + HCl CH3CH2Cl

CH3- CH3 + CH2= CH2 + Cl2 2CH3CH2Cl

1. thit b gia nhit

2. thit b clo ha (on nhit, pha kh): vi C2H6: Cl2= 4:1 v t = 400 - 450oC

3. thit b trao i nhit (ngng t)

4. thp chng tch C2H5Cl v HCl

5. my nn

6. thit b phn ng c xc tc : hydroclo ha ng chm

7. Thp chng tch C2H5Cl, etan cha phn ng, HCl v C2H4nu d1.5. Qu trnh clo ha parafin cao phn t

Qu trnh clo ha cc parafin cao phn t nhm mc ch thu cc sn phm sau:

C2H4

C2H6

Cl2 2

4 7

1

5

1

63

C2H5Cl

- Trong cng nghip da: chng thm nc

Tn thng mi ca cc dn xut Clo parafin (Witaclo) ca hng Dynamit Nobel:


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C10- C13: 49% Cl Witaclo 149

57% Cl Witaclo 157

C14- C17: 40% Cl Witaclo 340

50% Cl Witaclo 350

C20- C28: 20% Cl Witaclo 520

40% Cl Witaclo 540 ...

iu kin phn ng:

o

Clo ha pha lng

o

Nhit thp ( trnh sn phm c mu)

dng nh sng khi mo cho phn ng, v vy cho php thc hin phn

ng nhit t 80 100oC

Thit b phn ng:

o C ngun sng

o Sc Cl2vo pha lng parafin

o

C trao i nhit trnh sn phm c muSn phm: sn phm cha hm lng clo cao nht khong 71 72%. Nu hm

lng clo cao hn th nht sn phm s cao.

2. CLO HA OLEFIN: chia lm 2 qu trnh

- cng Cl vo ni i (Cl2, HCl, HOCl): ph bin

th t H t t C h kh b t Cl t h kh


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- th nguyn t H trn nguyn t C no hoc khng no bng nguyn t Cl trong pha kh

2.1. Cng vo ni i

Cng Cl2:

Phn ng cng Cl2vo ni i c th tin hnh trong pha kh hoc pha lng

pha kh: c ch chui gc nhit cao, khi

Cl* + C = C Cl - C - C*

Cl - C - C* + Cl2 Cl - C - C - Cl + Cl

*

pha lng: c ch cng i in t vi s to thnh phc v trung gian di tc

dng ca xc tc acid khng proton (FeCl3, AlCl3) ng thi xc tc ny va

lm dung mi cho qu trnh

Trong 2 qu trnh ny qu trnh pha lng c ng dng nhiu trong cng nghip.

Phn ng :

Nguyn tc clo ha pha lng: sc cht phn ng dng kh cng nh kh Cl2long

sy kh qua mi trng lng; phn ng xy ra trong pha lng nhit 70 - 1000C.

T l cht phn ng hu c : Cl2tng ng vi t lng c thm mt lng

d nh olefin ( 5%) bo m chuyn ha hon ton Cl2

CH2= CH2 + Cl2 CH2= CH2 H2C - Cl H2C - CH2

ClCl H2C+ Cl Cl

phc phc

+ FeCl3- FeCl4

- + FeCl4-- FeCl3

Khi thc hin phn ng vi dung dch nc Clo c ch phn ng nh sau:

CH2= CH2 CH2= CH2

Cl - CH2- CH2+ CH2- CH2

+ H2O

H+

+Cl2 - Cl+


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i vi ng ng ca etylen v nhng dn xut ca chng, khi tham gia phn

ng cng hp HOCl th nguyn t Cl s nh vi nguyn t C d hydro ha nht

(tc nguyn t C c cha nhiu nguyn t H nht). Chng hn: CH3- CH = CH2 + Cl2 + H2O CH3- CHOHCH2Cl

1 - clopropanol - 2

Cng bng HCl

- Phn ng cng HCl vo olefin c thc hin khi c tc ng ca xc tc

Chng hn: CH2= CH2 + HCl CH3- CH2ClXc tc: l cc acid khng proton thng l FeCl3hoc AlCl3

Phn ng thc hin theo c ch i in t:

- i vi nhng ng ng ca etylen v nhng dn xut ca chng, khi tham gia phn

ng cng HCl th tun theo qui tc Maccopnhicop

Chng hn: R - CH = CH2 + HCl R - CHCl - CH3

2.2. Cc sn phm ca phn ng cng Clo vo olefin

ClCl Cl OH

phc phc etylen clohydrin

- H+

CH2= CH2 CH2= CH2 CH3- CH2

+ CH3- CH2Cl

HCl

phc phc

+HCl

+ MCl3

- MCl4-

+ MCl4-

- MCl3

- Cn li:

+ sn xut etylen diamin dng lm cht c ch n mn acid

i h t l di i t t ti id (EDTA)


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iu ch etylen diamin tetra acetic acid (EDTA)

cht to phc vng cng (chelat)

+ sn xut cao su chu xng du: polysulfitc mi, khng lo ha

n CH2Cl - CH2Cl + n Na2SO4 (-CH2- CH2- S4-)n + 2n NaCl

+ dng lm cht dn Pb trong xng c nc Pb

Pb(C2H5)4(TEL): nc Pb khi phn ng trong ng c s hnh thnh

PbO2 th rn gy nhim, n mn ng c, ng dn khi. Nu cho

thm DCE vo nc ch s to ra PbCl2bay ra cng kh thi.

2.3. Cc phng php sn xut VCM

Cc phng php sn xut VCM hin nay c hoc khng thng qua giai on to

thnh DCE gm 5 qu trnh chnh sau:- Hydroclo ha acetylen: cng HCl vo C2H2

- Clo ha etylen: cng Cl2vo C2H4to thnh DCE v crackinh DCE

- Kt hp hydroclo ha v clo ha vi nguyn liu l C 2H2v C2H4

- Oxyclo ha C2H4

- Kt hp Cl2ha v oxyclo ha C2H4

2.3.1. Qu trnh hydroclo ha C2H2

Phn ng: CH CH + HCl CH2 = CHCl H0

298= -24,6 kcal/mol

CH2NH2+ 4 HO-CH2-CN

-4H2O

HCHO + HCN

CH2NH2

CH2- N(CH2CN)2

CH2- N(CH2CN)2

+ H2OCH2- N(CH2COOH)2

CH2- N(CH2COOH)2

EDTA

- nu s dng HCl kh th c th dng thp Cacbon, khng cn dng thp chng n mn

nhng yu cu nguyn liu phi sch, C2H2khng cha cc hp cht ca S, P gy n

mn thit b; HCl khng cha Cl2 nu khng s gy n


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mn thit b; HCl khng cha Cl2nu khng s gy n.

-phn ng ph: CH2= CHCl + HCl CH3- CHCl2 (1,1 - DCE)

S cng ngh : hnh 103 - trang 382 - Ptrochimie

S cng ngh hydroclo ha acetylen sn xut VCMMt vi thng s: + TBP c H = 4m, tb= 2m

+ Thi gian sng ca xc tc : 2000h

Cng ngh mi: Phn nng i ra t thp tinh ch VC cha ch yu l 1,1 - DCE

s c dng nh mt dung mi hp th C2H2 tch kh thi, khi iu kin lm vic

ca thp stripping s mm hn.


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ca thp stripping s mm hn.

2.3.2. Qu trnh clo ha C2H4

C2H4r hn C2H2t 2 - 3 ln.Cc qu trnh gn y u p dng cng ngh Clo

ha hay Oxyclo ha C2H4hay p dng c 2 qu trnh ny sn xut 1,2 - DCE sau

s crackinh 1,2 - DCE tng hp VC.

Phn ng :

(1) CH2= CH2 + Cl2 CH2Cl - CH2Cl H0298= - 52 kcal/mol

(2) CH2Cl - CH2Cl CH2= CHCl + HCl H0

298= + 16 kcal/mol

+ Phn ng (1): c th tin hnh trong pha kh, tuy nhin qu trnh trong pha lng vi

xc tc clorua kim loi ph bin hn. Mi trng lng y l DCE hi lu.

Yu cu i vi nguyn liu:

- C2H4c sch cao trnh sn phm ph v cc halogenua ca C3, C3=rt kh

tch khi VCM

- Cl2phi sch v c pha long bng khng kh c ch cc phn ng Clo

ha su hn to ra triclo...

Mt s DCE:

1,1-DCE : ts= 57,2oC

1,2-DCE : ts= 84oC

1,1,1-TCE : ts= 74oC

1,1,2-TCE : ts= 110-115

o

CS cng ngh: hnh 104 - trang 384 - Ptrochimie


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S cng ngh clo ha Etylen sn xut VCM

Thuyt minh: Kh giu Cl2v kh giu C2H4c phun vo ng hi lu ca

1,2 - DCE . Nhit ca thit b phn ng c duy tr 40 - 500C, p = 5 bars, xc tc

l FeCl3. Hn hp kh ra khi thit b phn ng c ngng t tch kh khng ngng

(C2H6, N2). Mt phn DCE c tun hon trc tip li thit b phn ng, phn cn li

c ra bng nc, sau lm lnh v lm tinh trong mt hoc 2 thp.

y l mt phn ng rt chn lc, tinh khit ca 1,2 - DCE sau thit b phn

ng l 99% v t n 99,97% sau khi tinh ch. Hiu sut qu trnh rt cao: 98% so vi

C2H4cng nh Cl2.

Cng ngh mi: (s HTC) cng ngh ph bin nht hin nay l cng ngh clo

ha nhit cao (HTC). Thit b phn ng lm vic nhit 1000C v khng c s

gii nhit m kt hp nhit phn ng dng bc hi DCE v chng tch hn hp phn

ng. Thp phn ng c gi l thp CD (distillation and catalisation).+ Phn ng (2): c th tin hnh bng 2 phng php

- dng xc tc: Al2O3 c b sung NH4Cl trn than hot tnh nhit 200 -

Dy chuyn ny c giai on ti sinh Cl2 t sn phm ph l HCl theo phn ng

Deacon:

2 HCl + 0,5 O2 Cl2 + H2O H0

298= - 13,7 kcal/mol


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- xc tc : CuCl2c b sung cc clorua kim loi t him

- nhit : 350 - 4000C

- p sut : 1 - 2 bars

- %C khong 75%

- TBP loi tng si

S : Cng ngh Clo ha hin i HTC

2.3.3. Qu trnh kt hp hydroclo ha v clo ha

trnh sn phm ph l HCl t qu trnh clo ha C2H4, mt phng php ci tin

42

kh thi

phn nng

1

6

5

3

C2H4

Cl2

DCE

VC

DCE cha chuyn hat qu trnh sn xut

DCE

1. thp phn ng CD (xc tc v chngct)2. thit b ngng t3. thit b phn ly4. thit b lm lnh su5 thp chng tch VC6. thp tch phn nng thu hi DCE

Cng ngh mi cho phng php ny dng trc tip mt phn on du nh sn

xut hn hp C2H4 v C2H2c thnh phn thch hp thc hin cc phn ng trn m

khng qua giai on tch v tinh ch C2H4v C2H2m thay th bng cc giai on d dng


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hn l tch v tinh ch VC v DCE.

Qu trnh Kureha (s cng ngh hnh 105 - trang 387 - Ptrochimie)s dng

nguyn liu l phn on Naphta gm cc giai on sau:

Qu trnh Kureha sn xut VCM t etylen v acetylen

a). Nhit phn bng O2trong l t:

L t gm 2 phng t chng ln nhau (kiu Wulf). phn th nht kh thi hi luc t chy bng O2 vi s c mt ca hi qu nhit. Nhit c th t ti 1600 -

18000C. Phn on naphta c un nng trc n khong 5000C s c phun vo

Hm lng ca hn hp (C2H4+ C2H2) trong kh sn phm khong 20%V

Thnh phn ca kh nhit phn tiu biu nh sau:

% mol % mol


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N2

O2

H2

CO

CH4

2,7

1,0

28,8

13,3

11,0

CO2

C2H2

C2H4

C2+

Aromatic

21,2

9,1

10,8

1,0

1,1

b) Nn v tinh ch (khng c trong s )

Hn hp kh sau khi ti s c nn n 6 7 bars, sau lm lnh n - 200C

tch phn lng aromatic, trong benzen t60 90% m.

Giai on tinh ch c thc hin bng ct hp th v stripping (dung mi c th l

DCE) tch loi C3+v s dng lm nhin liu.

c) Phn ng hydroclo ha C2H2

Ti u vo ca thit b phn ng hydroclo ha acetylen c lp t h thng o lu

lng C2H2 iu chnh t l HCl thch hp.

iu kin vn hnh ging phng php u tin.

Hiu sut VC t c 95 - 98% theo acetylen.Hn hp kh thu c s cho qua ct hp th (bng DCE t ct stripping) tch

C2H4v kt hp vidng VC ca giai on sau ri i qua ct stripping tch DCE (DCE

ny gm c 1,1 - DCE l sn phm ph ca qu trnh ny v 1,2 - DCE cha b crackinh ca

giai on sau). Dng DCE ny mt phn dng lm dung mi cho ct hp th, mt phn

dng lm mi trng lng cho phn ng clo ha etan.Phn VC ly ra nh ct stripping i vo b cha tip tc a i tinh ch.

d) Phn ng clo ha C2H4

Kh thi khng cha C2H4, C2H2 c s dng lm nhin liu cho l t v l

crackinh DCE.

DCE c tinh ch trc khi a vo thit b crackinh


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e) Qu trnh crackinh DCEPhn ng crackinh khng xc tc c thc hin di p sut 7 bars 450 5500C,

chuyn ha khong 60%, hiu sut VCM khong 96%.

Acid HCl c tch ra trong ct u tin s quay li thit b hydroclo ha C2H2. Cn

VC s c tinh ch ti ct stripping ca vng chuyn ha acetylen.

Cc cu t nh c thi v s dng lm nhin liu.

2.3.4. Qu trnh oxyclo ha etylen

Qu trnh ny tn dng HCl t nhiu qu trnh sn xut clo ha (phn ng th), qu

trnh nhit phn clorolyse c s tch HCl tng hp DCE sau s crackinh DCE.

Phn ng :

CH2= CH2 + 2 HCl + 0,5 O2 CH2Cl - CH2Cl + H2O H0

298= - 65.7 kcal/mol

- y l mt phn ng ta nhit rt mnh

- xc tc : halogenua kim loi c ha tr thay i, ph bin nht l CuCl2c thm mt

s halogenua kim loi kim khc (ty thuc tng hng) trn cht mang l Al2O3.

- Yu cu nguyn liu: C2H4sch C2H2v n d to hp cht polyclo to nhakhi xc tc ; Cn Cl2th yu cu sch Br2v cc hp cht lu hunh, photpho.

- C ch: phn ng xy ra qua 2 giai on

+ giai on 1: CH2= CH2 + 2 CuCl2 CH2Cl - CH2Cl + Cu2Cl2

+ giai on 2: Cu2Cl2 + 0,5 O2 CuO.CuCl2

CuO.CuCl2 + 2 HCl 2 CuCl2 + H2O

- mc chuyn ha: %CC2H2, HCl= 93 - 97%

- chn lc : %S = 91 - 96%

S cng ngh: s cng ngh oxyclo ha etylen bng a.HCl

kh thi


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C2H

kk

HCl

d u

lmlnh

NaOHH2O

2 3

6

7 8

9

phn onnh (thuhi DCEhoc t)

DCE

nc thi (thu hiDCE hoc x l)

dd HCl

1. thit b gia nhit 5. Thit b tch kh lng2. thit b phn ng 6. Thit b phn ly 2 pha lng

3. thp kh HCl 7. Thit b ra DCE4. thit b lm lnh ngng t 8. Thp chng tch9. thit b phn ly kh - lng

2.3.5. Qu trnh kt hp gia clo ha v oxyclo ha etylen

S cng ngh: hnh 106 - trang 394 - Ptrochimie


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2.3.6. Thit b oxyclo ha hin iTBP l thit b vi lp xc tc gi si: t = 220 4000C; p = 0,2 0,5 MPa; ht xc tc c = 40 80

m cha 7 20% CuCl2. Nhit phn ng dng sn xut hi nc.

u: ng u nhit v tng


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H2Okk (O2)

HCl

C2H2mt sng phn phi kh

cyclon tch sn phmsn phm

II. Qu trnh clo ha cc hydrocacbon thm

Gm 3 qu trnh chnh


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- th nguyn t H trn nhn thm bng nguyn t Cl - cng nguyn t Cl vo nhn thm

- th nguyn t H trn mch nhnh bng nguyn t Cl

1. Th nguyn t H trn nhn thm bng nguyn t Cl

Phn ng

c im

-phn ng xy ra trongpha lng trong cc dung mi nh cloroform CHCl3, CS2v

l mt phn ng ta nhit

- iu kin thng phn ng ny xy ra chm, tng vn tc phn ng th s

dng xc tc nh mui clorua kim loi: FeCl3...

- c ch phn ng: c ch th i in t v xy ra qua s to thnh phc v phc

- nu cho tha Cl2 v thi gian phn ng ko di th qu trnh th s xy ra su hn

v c th xy ra hon ton to CCl6. Tuy nhin mi giai on tip theo s xy ra

chm hn giai on trc.2. Cng vo nhn thm

Phn ng cng Cl2vo nhn thm to ra nhiu sn phm khc nhau theo c

+ Cl2

Cl

+ HCl -H > 0

Cl+ClCl+ Cl2 + FeCl3

- FeCl4-

+HCl + HCl + FeCl3

C6H6Cl* + Cl2 C6H6Cl2 + Cl

* C6H6Cl3*

C6H6Cl3* + Cl2 C6H6Cl4 + Cl

* C6H6Cl5*

C6H6Cl5*

Cl2 C6H6Cl6 Cl*


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C6H6Cl5 + Cl2 C6H6Cl6 + Cl 3. Th trn mch nhnh

Phn ng ny xy ra nhit ln hn nhit phn ng th vo nhn thm

v phn ng xy ra theo c ch chui gc khi c chiu sng. V trnh th vo

nhn thm ngi ta khng dng xc tc.

Cl2 + h 2 Cl*

C6H5CH3 + Cl* C6H5CH2Cl + H

*

CHNG IV: QU TRNH OXY HA

1. Nhng c trng v qu trnh oxy ha


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