tao noi c-halogen

7/24/2019 Tao Noi C-halogen

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To ni carbon-halogen

Mc tiu

2

Nm c phng php a halogen vo mchcarbon

Ghi nh mt s c ch phn ng quan trng

Vn dng kin thc vo bi tp thc t

Ni dung

3

Halogen ha hidrocarbon khng no bng phn ng cng

Halogen ha hidrocarbon bng phn ng th

Chuyn ha nhm chc khc thnh halogen

nh ngha phn ng halogen ha

Phn ng halogen ha l a mt hay nhiu nguynthalogen vo hp cht hu c.

Halogen a vo khc nhau tn phn ng khcnhau.F flour haCl clor haBr brom haI iod ha

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Nguyn tc to ni C-halogen

Phn ng th

CH4 Cl2 CH3Cl HCl+ +

H2C CH CH3 H2C CH CH2 ClCl2+ HCl+

to

Br

Br2 HBr+ +

H3C CH2 OH H3C CH2 Cl H2OHCl+ +ZnCl2

H3C Cl NaI NaClH3C I+ +

5

Phn ng cng

H2C CH2 Br2+ BrH2C CH2Br

HC CH HCl+HgCl2

H2C CHCl

6

ng dng quan trng ca vic to niC-halogen

Hp cht halogenur alkil l cht trung gian quantrng trong hu ht cc qu trnh chuyn ha thnhnhm chc khc.

R X R Z+ -

X: F, Cl, Br, I

Z: R', CN, OH, OR', NH2...

7

Halogen ha hidrocarbon khng no bngphn ng cng

Cng halogen X2 vo ni i hay ni ba cahidrocarbon khng no to dn xut dihalogen haytetrahalogen (fluor phn ng kh khn, iod khngphn ng).

H2C CH2 Br2+ BrH2C CH2BrCCl4

HC CH Br2+CCl4

Br HC CH Br Br2

Br2HC CHBr 2

Cng X2 vo ni i

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C ch phn ng

To cation halonium vng (bromonium, cloronium)

H

CH3

H

H3C

Br Br

H H

H3C CH3

Br+

+

Br-a b

Phn ng cng X2 vo ni i xy ra theo scng

trans xy raqua 2 giai on.

9

M vng cation halonium

treo-()-2,3-dibromobutan

H H

H3C CH3

Br+

Br-a b

H3C H

HH3C

Br

Br

H

H

CH3

H3CBr

Br

a

bS

S

R

R

10

Cng X2 vo ni ba

X2 cng vo ni ba ca alkin c th cng 1 phnt X2hay 2 phn t X2 ty thuct l mol gia X2 v alkin.

Gia i on cng 1 phn t X2 vo ni ba s to thnhalken bn nht (cu hnhE).

HC CH + Br2 C C

H

Br H

Br

(E)-1,2-dibromoeten

11

Gii thch

(E)-But-2-en + Br2 meso-2,3-dibromobutan

But-1-in + Br2 (E)-1,2-dibromo-but-1-en

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Br2+

Br

H

H

Br

Ciclopenten trans-1,2-dibromopentan

i vivng cha ni i th phn ng cng X2 cho

sn phm c 2 halogen hai pha ca vng.

13

Cng HX vo ni i

Cng HX vo ni i ch to thnh dn xutmonohalogen.

phn ng: HI > HBr > HCl

14

CH CH2H3C H-X+ CH CH3H3C

X

C ch phn ng

Phn ng qua trung gian carbocation.

C C H X+ C C

H

X-+ C C

H

X

15

HBr+CH CH CH3H3C CH2 C HB r C H3H3C

Alken i xng

Alken bt i xng

HBr+CH CH2H3C

CH2 CH2BrH3C

CHBr CH3H3C

a

b

To sn phm theo hng no ?

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Qui tc Markovnikov cng HX vo ni i

Phn ng cng HX vo ni i qua trung gian

carbocation.

Carbocation no bn s tn ti lu hn.

Sn phm chnh to thnh theo hngcngH vo carbon mang nhiu H nht.

CH2 CH2+H3C CH

+ CH3H3C

A B

17 18

HBr+CH CH2H3C

CH CH3H3C

a b

CH2 CH2H3C

CH2 CH2H3C

Br

CH CH3H3C

Br

Trung gian ben

San pham chnh

19

H3C CH CH CH3 HBr+

C CH CH CH3 HBr+

Sn phm no to thnh ? Mt s trng hp xy ra chuyn v nhm to racarbocation bn hn.

Khi vit sn phm ch xem c th xyrachuyn v hay khng.

HC C

C

H

H3C

H3C

H

H

HCl+ CH C

C

H

H3

C

H3C

H

H

Cl

H H2C CH

C

Cl

H3

C

H3C

H

H

+

50%50%

20

C ch ?


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C ch chuyn v

C C

C

H

H3C

H3C

H

H

H C C

C

H3C

H3C

H

H

H

H H H

Carbocation II Carbocation III

21

Nhm chuyn v c th l H cng c th l metil.

C C

C

CH3

H3C

H3C

H

H

HCl+ C C

C

CH3

H3C

H3C

H

H

Cl

H C C

C

Cl

H3C

H3C

H

H

+

H H H CH3

H

22

C ch ?

Cng HX vo ni ba

Phn ng c th cng 1 phn t HX ha y 2 phn tHX ty thuc t l mol gia HX v alkin.

Cng mt HX vo ni ba xyra ging nh cng HXvo alken (qui tc Markovnikov).

C CHH3C HBr+ C CH2H3C

Br

23

Giai on cng HX th 2 vo sn phm ca gia ion1 theo scng hngp-.

C CH2H3C

Br

H Br+ C CH3H3C

Br

Br-

C CH3H3C

Br

Br

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Cng HX vo ni i c s khi mo ca peroxid

Phn ng xy ra ngc vi qui tc cng Markovnikov,

gy ra bi peroxid gi l hiu ng peroxid (ch xy ravi HBr).

CH CH2H3C HBr ROOR'

CHH3C

CH2 CH2H3C

Br

CH3

Br

+

Theo Markovnikov

Ngc Markovnikov

Ti sao ?

25

Phn ng xy ra quac ch gc t do (khng qua trunggian carbocation).

R O O R R O2

Peroxid

R O HBr+ R OH Br+

CH CH2H3C Br+ CH CH2BrH3C

CH CH2H3C + CH2 CH2BrH3CHBr Br+

26

CH CH2H3C Br+

CH CH2H3C

CH CH2H3C

Br

Br

Goc t do bac I

Goc t do bac II

CH2 CH2H3C

Br

bn gc t do: III > II > I

27

To lin kt C-halogen bng phn ng th

Halogen ha alkan hay nhm alkil

Phn ng thng tin hnh vi Cl2 hay Br2 (fluor phnng kh khn, iod khng cho phn ng).

CH4 Cl2+ CH3Cl HCl

AS+

H2C CH CH3 H2C CH CH2ClCl2+ to

HCl+

CH3 CH2ClCl2+AS

HCl+

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C ch phn ng halogen ha

Phn ng xy ra theo c ch gc t do.

ASCl Cl ClKhi mao

Cl R H+ R HCl+

R + Cl2 R Cl Cl+

Phat trien mach

Cl + Cl Cl2

R + R R R

R + Cl R Cl

Tat mach

29

Halogen ha alkan

phn ng ca halogen: F2

> Cl2

> Br2

> I2

phn ng ca carbon khi to gc t do:

R

R

R

H R

H

R

H H

H

R

H> >

III II I

30

Phn ng clo ha thng to ra hn hp sn phm.

Cl2+ AS

CH3CH2CH2CH3 CH3CH2CH2CH2Cl CH3CH2CHCH3+

Cl

n-Butan clorur n-butil clorur s-butil

30% 70%

Brom c phn ng km hn clo nhng phn ngbrom ha c tnh chn lc hn clo ha.

Br2+ AS

CH3CH2CH2CH3 CH3CH2CH2CH2Br CH3CH2CHCH3+

Br

n-Butan Bromur n-butil Bromur s-butil

2% 98%

31

Halogen ha nhm alkil v tr ca C=C

H H

H-alil H-benzil

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H-alil c th tham gia halogen ha vi iu kinnhit cao.

to

H2C CH CH3 Cl2+

H2C CH CH3

Cl Cl

H2C CH CH2

Cl

33

H-benzil cng tham gia phn ng halogen ha viiu kin quang ha (chiu sng).

CH3AS

CH2

Cl

Cl2+

34

35

+H2C CH CH2 CH2 CH3 Cl2to

CH2 CH2 CH3 + Cl2to

Sn phm to thnh ?Kh nng phn ng ca H-alil v H-benzil cao hn Htrong phn t alkan do gc alil v benzil c cnghng lm an nh gc t do.

H2C CH CH2 H2C CH CH2

CH2 CH2 CH2

CH2

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phn ng th ca H: bc I < II < III < alil < benzil

an nh ca gc t do:

37

CH3 R2CH R3C H2C CH CH2 C6H5-CH2< < < <


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Halogen ha nhn hng phng

Ar H X2+ Ar X HX+

+ Br2

Br

HBr+FeBr3

Vng benzen c th tham gia phn ng halogen ha

vixc tc acid Lewis (FeBr3, AlCl3).

41

phn ng ca halogen: F2 > Cl2 > Br2 > I2

Khng dng F2, I2 fluor ha trc tip nhn benzen.

FeBr3

CH3

+ Br2

CH2Br

CH3

Br

AS

42

fluor hay iod ha vng bezen phi tin hnh quatrung gian mui diazonium.

HNO3

H2SO4

NO2

Fe+HCl

to

NH2

NaNO2/HCl

0-5oC

N

N

Cl-

43

N2+ Cl-

BF3/HF

CuCl/HCl

CuBr/HBr

KI

F

Cl

Br

I

N2+

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Halogen ha alcol

Phn ng th gia alcol vi:

HX

Hp cht cha halogen ca phospho(PX3, PX5, POCl3)

Hp cht cha halogen ca lu hunh(SOCl2, SO2Cl2)

45

Phn ng gia alcol vi HX

R OH H X+ R X H2O+

phn ng ca HX: HI > HBr > HCl

phn ng ca alcol: bc 3 > 2 >1

46

HCl phn ng km nht cn thm xc tc ZnCl2khiphn ng vialcol bc 1 v 2, i vi alcol bc 3phn ng d dng vi HCl nhit thng.

OH

H3C

H3CH3C

+ HCl Cl

H3C

H3CH3C

H2O+

HBr+H3C CH2 OH H3C CH2 Br H2O+NaBr + H2SO4

to

+H3C CH2 OH HCl

ZnCl2H3C CH2 Cl H2O+to

47

C ch phn ng

Alcol bc 3 phn ng theo c ch SN1

OHR

R

R

HX+ OH2+R

R

R

X-+

OH2+R

R

R

R

R

R

H2O+

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R

R

R

X-+ XR

R

R

Alcol bc 1 phn ng theo c ch SN2

R OH

H2O

+ HX R OH2+ X-+

X R OH2 R X +

49

Alcol bc 2 cth xyra theoc ch SN1 h a y SN2

Khi phn ng xy ra qua c ch SN1tn ti trung

gian carbocation c th xy rachuyn v nhmto ra carbocationbn hn.

H3C CH C H CH3

CH3

OH

+ HX

H3C CH CH CH3

CH3

X

H3C C CH2 CH3

CH3

X

50

Sn phm no to thnh nhiu hn ?

Khi halogen ha vng c sc cng ln thng c sm vng to vng ln hn nhm gim sc cng cavng.

H

OH

CH3

CH3

HCl+

Cl

CH3

CH3

51

C ch ?

Phn ng gia alcol vi hp cht c halogen calu hunh.

R OH SOCl2to+ R Cl SO2 HCl+ +

Alcol bc 1 v 2 phn ng d dng vi clorur

tionil to ester clorosulfit.

O

H3C

C2H5

H

H

S O

Cl

Cl

-HClO

H3C

C2H5

H

S O

Cl

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un nng ester clorosulfit chuyn thnh clorur alkil.

O

H3C

C2H5

H

S O

Cl

toH3C

C2H5

H

O

S O

Cl H3C

C2H5

HCl SO2+

Cl- tc kch vo C+ cng pha vi hng OH xut ra nnphn ng th SNi xy ra sn phm c s lu gi cuhnh (phn ng th SNi).

53

Nu hn hp c nng Cl- ln (c s hin din cabaz) th phn ng xy ra theo c ch SN2 sn phm

bnghch o cu hnh.

O

H3C

C2H5

H

H

S O

Cl

Cl

-HClO

H3C

C2H5

H

S O

ClCl-

Cl

CH3

C2H5

H

SN2SO2+ + Cl

-

54

Vi alcol thuc loi alil th phn ng th ni phn tSNi xyra cs chuyn vnialil

H3C CH CH CH2 OH SOCl2+ H3C CH CH CH2 +

Cl

SO2 HCl+

H3C CH CH C H2

Cl

55

C ch s chuyn v alil

H3C CH CH CH2 OH SOCl2+ H3C CH CH CH2 O SOCl HCl+

CH

Cl

HC CH2

O

S

O

+ SO2H3C CH CH CH2

Cl

H3C

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Phn ng gia alcol vi hp cht c halogen ca phospho

R OH PCl5 HCl POCl3+ R Cl + +

PBr3 H3PO3R OH + R Br +3 3

OH PBr3+ Br

H3PO3+3 3

57

C ch phn ng

To ester phosphit.

Phn gii ester thnh R-X vi acid HBr.

OH PBr3+ O

3

3

PHBr+ 3

O

3

PHBr+ 3

Br3

H3PO3+

58

Alcol bc 1 xy ra theo c ch SN2, alcol bc 3 xyratheo c ch SN1.

Phn ng xy ra theo c ch SN2 c s nghchchuyn cu hnh do anion Br- tc kch pha i dinca s t ni C-O.

59

Hp cht PI3 khng bn nn khi phn ng thngdngP+I2 iu ch R-I.

R OH + P I2+ R I H3PO3+3 33/2

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u im ca tc nhn cha halogen ca S v P

Tc nhn SOCl2

, PBr3

, PI3

halogen ha alcol bc 1 vbc 2hn ch c s chuyn v, sn phm chuynv khng ng k so vi dng HX.

Nhc im ca tc nhn cha halogen ca S v P

Phn ng to ra acid mnh trong dung dch (HCl,HBr) ch dng khicht nn alcol bn vi acid.

61

Phn ng gia alcol vi cc hp cht khc

p-tosil clorur

Phc ca Ph3P (triphenil phosphin) chuynalcol thnh ion alkoxiphosphoni (Ph3P+-OR)

62

Phn ng gia alcol vi p-tosil clorur (p-TsCl)

H3C S Cl

O

O

HCl+H3C S Cl

O

O

R OH +H3C S O

O

O

R

63

p-TsCl l tc cht quan trng nhm to nn chttrung gianp-TsO-R. y l cht trung gian trong huht cc chuyn ha nhm chc do p-TsO l nhmxut tt cho phnng th SN2.

Tc nhn thn hch Nu- tc kch vo C ngchng nhm xut p-TsO nn sn phm nghchchuyn cu hnh.

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CH3

SO O

Cl

OH

+

CH3

SO O

O

Nu-

CH3

SO O

O-

Nu+

65

to ni C-halogen th Nu- l cc mui v c cacc halogen nh NaCl, NaBr, NaI.

CH2 OHCHC

H3C

H3C

1. p-TsCl

2. LiClCH2 ClCHC

H3C

H3C

Phn ng khng xy ra chuyn v so vi dngSOCl2 hay HCl.

66

Phn ng gia alcol vi phc ca Ph3P

Phc gia Ph3P v Br2

Ph3P Br2+ Ph3P

Br

Br

Ph3P

Br

Br

R OH+ +Ph3P O RBr- HBr+

+Ph3P O RBr-

+ Br- Ph3P O R Br+

SN2

R OH R Br PPh3

Br2

67

Ph3P Br2+

CH3

CH3C8H17

HO

CH3

CH3C8H17

Br

SN2

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Triphenilphosphin clorur

Ph3P CCl4+ Ph3P Cl CCl3+

HClPh3P Cl + R OH Ph3P O R +

SN2Ph3P O R Cl-+ Ph3P O R Cl+

Ph3P

CCl4R OH R Cl

69

Triphenoxiphosphit

CH3I(PhO)3P (PhO)3PCH3 I-

+ +

(PhO)3PCH3 + R OH (PhO)2P

CH3

OR PhOH+

(PhO)2P

CH3

OR I-+ (PhO)2P

CH3

O R I+

(PhO)3PR IR OH CH3I+

70

O-phenilen clorophosphit

R OH

O

P

O

Cl

O-phenilen clorophosphit

+

O

P

O

OR HCl+

SN2O

P

O

OR + I2 R I

O

P

O

O+

R OH

O

P

O

Cl

+ R II2

71

Halogen ha eter

Phn ng gia eter v acid HX

Sctni C-O ca eter xy ra vi acid HX, un nng.

R O R HX to

R X R OH+ +

R OH HX+ R X H2O+

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phn ng ca HX: HI > HBr > HCl (HF khngcho phn ng).

(H3C)2HC O CH(CH3)2 HBr, 120o

C (H3C)2HC Br 2 H2O+

O CH3

HI, 120oCOH H3C I+

Phn ng 2 ch sinh ra 1 hp cht halogenur alkil,ti sao ?

73

C ch phn ng

R O R' H

+

R O R'

H

X

-

R X R' OH+SN1 hay SN2

C ch SN2 xy ra khi eter c cc nhm alkil bc 1,bc 2.

C ch SN1 xy ra khi eter c nhm th bc 3, benzilhay alil.

74

Eter bt i xng s t ni C-O xy ra tinhm alkil no ?

H3C CH

CH3

O CH2 CH3

a b

75

Nhm alkil bc 1, bc 2 phn ng th X- xy ra theoc ch SN2 X- tc kch vo carbon t chngngi nht.

H3C CH

CH3

O CH2 CH3HI

H3C CH

CH3

OH H3C CH2 I+

HIH3C CH

CH3

I H3C CH2 OH+

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Nhm alkil bc 3 phn ng th X- xyra theo c chSN1 X- tc kch vo carbon bc 3.

Phn ngxy rac ch th SN1 thng i km phnng kh E1 do s kh H ca carbocation trung gian.

O

C

CH3

CH3CH3

HBrOH

H3C C

CH3

CH3

Br+

77

H2C C

CH3

CH3H

H2C C

CH3

CH3

Phn ng th SN1 cng x y ra vi trng hp cnhm alkil l benzil hay alil do carbocation to thnhcan nh nh s cng hng.

H3C

CH2

O

CH2

H3C

CH2

O

CH2

CH

CH2

78

S cng hng ca nhm benzil v alil

CH2+ CH2 CH2 CH2 CH2

+

H2C CH CH2+ +H2C CH CH2

79

Trng hparil alkil eter th ch t ni gia oxigenv alkil to thnh phenol v halogenur alkil (khngto thnh alcol v halogenur aril).

O

HII+OH

HII OH+

V sao ?

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O O O O O

S cng hng ca oxigen vi vng benzen

Ni gia Cbenzen-O c mt phn ca ni i kht hn ni gia Calkil-O.

81

Phn ng gia eter v BX3 (bor trihalogenur)

Dng HX halogen ha eter nhng nhm chckhc trong phn t c th b phn hy (thy giiester, amid) cn tc nhn m du hn.

BBr3, R2BBr, (CH3)3SiI

82

Brom ha eter bng BBr3

R O R BBr3 H2O+ R Br B(OH)3 HBr+3 3 + +2

Phn ng xy ra vi hiu sut cao, c bit l metil eter.

83

R O R

BBr2

+Br- R O BBr 2 R Br+

+R O R BBr2+

Br

R O R

BBr2

Br-

B(OH)3 HBr+2R O BBr 2 H2O+ R OH +

C ch phn ng

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S tc kch ca Br- nhm ct t ni C-O xy ra theoc ch SN2 h a y SN1 ty thuc nhm alkil ca eter.

Nhm alkil bc 1, bc 2 th SN2

Nhm alkil bc 3, benzil, alil th SN1

85

Iod ha bng trimetilsilil iodur (CH3)3SiI

H2O+ ++R O R (CH3)3SiI R I R OH (H3C)3Si OH+

Trimetilsilil iodur kh t tin nhiu phng phpkhc c s dng nhm tng hp gin tip tc nhnny ngay trong mi trng phn ng.

(CH3)3SiCl NaI (CH3)3SiI NaCl+ +

PhSi(CH3)3 I2 PhI+ (CH3)3SiI +

86

+R O R R O R

Si(CH3)3

I-+(H3C)3Si I

R O R

Si(CH3)3

I-+ R O Si(CH3)3 R I+

H2O

R OH + (H3C)3Si OH

C ch phn ng

87

Halogen ha phenol v amin hng phng

Halogen ha phenol v amin hng phng xy ratrn cchidrogen ca nhn hng phng.

nh hng ca s halogen ha l v tr ortho v para.

Nhm OH v NH2 lm tng hot nhn hng phng thng xy ra sth nhiu ln trn nhn hngphng vkhng cn xc tc.

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OH

3 Br2

OH

+

BrBr

Br

3 HBr+

NH2

3 Br2

NH2

+

BrBr

Br

3 HBr+

89

Dng dung mi km phn cc nh CCl4, CS2 phnng ch xy ra1 ln th.

Khi t in hnh c thm acid HX th sn phm s xyra2 ln th.

OH

Br2

CCl4

HBr

Br2

OH OH

Br

Br

Br

90

Halogen ha acid

To halogenur acil

Tc nhn clorur tionil (SOCl2) chuyn nhm chcacid carboxilic thnh dn xut clorur acid.

R COOH SOCl2+ R COCl SO2 HCl+ +

Ngoi ra cn s dng PX3 hay PX5.

R COOH + PBr3H3PO3R COBr +3

R COOH + PCl5 POCl3R COCl + HCl+

91

Cc dn xut acid khc c iu ch bng cchcho acid HF, HBr, HI tc dng vi clorur acid.

HClR COCl + HX R COX +

X: F, Br, I

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C ch phn ng

R C

O

OH + O S

Cl

Cl

R C

O

O S

O

Cl HCl+

R C

O

O S

O

Cl Cl-+ R C

O

O S

O

Cl

Cl

SO2+R C

O

O S

O

Cl

Cl

R C

O

Cl + Cl-

93

Thay th nhm COOH bng halogen X

Phn ng Hunsdiecker

Xy ra khi un nng bui bcca acid carboxilic vi halogen.

R CH2 COOH Ag2O+ R CH2 COOAg2 H2O2 +

R CH2 COOAgBr2

toR CH2 Br CO2 AgBr+ +

Ch xy ra vi gc alkil bc 1

94

Halogen ha gc alkil ca acid carboxilic

Phn ng Hell-Volhard-Zelinsky

Acid carboxilic tc dng vi PBr3 cho sn phm thBr ti v tr C.

COOHP o

+ Br2COOH

Br

HBr+

95

Phn ng Kochi

Xy ra khi un nng acid carboxilic vi LiCl v ch tetraacetat.

C H C OO H

H3C

H3C

Pb(OCOCH3)4 LiCl CH

H3C

H3C

Cl LiPb(OCOCH3)3CH3COOH+to

+ + +

Phn ng c th xy ra vi gc alkil bc 2, bc 3.

96

tao noi c-halogen

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