2 (2)

i't\j LLiriiHM

UW KŁMLIlUNb

extinguishers, CFsCHCIBr (called halothane), used as an anesthetic, tri-and tetrachloroethenes, used as dry-cleaning solvents, and chlorofluoro-carbons or Freons (CC1₃F, CC1₂F₂, CC1F₃, CHC1₂F, CHC1F₂), used as refrigerants, aerosol propellants, and solvents. Teflon is a polymer of tetrafluoroethene. It is used in nonstick coatings, "Gore-Tex" fabrics, insulators, and many other things. Certain perfluorochemicals dissolve high percentages of oxygen and can be used as artificial blood. Many halogen-containing compounds are important pesticides.

REACTION SUMMARY Nucleophilic Substitution

+

Nu: + R—X -*- R — Nu + X"

or

Nu+ R — X -► R—Nu + X"

(See Table 6.1 for examples.)

Elimination

H

\    /

C = C /    \

base

I I

+ BH + X‘

—C—C

I I

X

Preparation of Freons

CC1₄ -HE-► CCI3F, CC1₂F₂, etc.

^SbF5

Preparation of Teflon

2chcif₂ —ęoo-aooĘę^ _Cp₂_=_CF2 + ₂hci cf₂=cf₂ P^ero*^ide.» ~(-CF₂CF₂—^

MECHANISM SUMMARY

W

MECHANISM SUMMARY

<S + 1 ó-	•I- / ,
Nu*’* *C* ’ * * L	------*- Nu i ' 1
L V J

Nu: + .it\C — L /

S^2 (Bimolecular Nucleophilic Substitution)

\

S^l (Unimolecular Nucleophilic Substitution)

\

_I slow.

.A\p — L

V

+ L'

+ Nu:

carbocation I

fast

"'^NKnu

or

•i AM

Nu^x i

E2 (Bimolecular Elimination)

<?

•'^s i V

* o

BH⁺

c=sc + r

4    \

El (Unimolecular El i mi nati on) H

J__l_

I I ^L

LEARNING OUJEC T1VES

l> I,

c— c¹ -»• l I I

L.............

1.    Know Lhe meanlng of: nucleophIMc subnll tuMon tbiUltiwi substrate, lmlrig group.

2.    Bo Idini I lar w tli l,ho eaainples of rtucleoplH 116 tubstityf llsUd fn labę 6.1.

3. Know the mann ng of: $^2 mechanUm, I nv^ris i mi uf upchani sin, ratuniliatlon, rate-deteminłMi I-Iiip*

*|» Know tho lwim las ff J||§ig    uh I

h.

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