6.21 reactions of alkenes with alkenes: polymerization

6.216.21

Reactions of Alkenes with Alkenes:Reactions of Alkenes with Alkenes:

PolymerizationPolymerization

cationic polymerizationcationic polymerization

free-radical polymerizationfree-radical polymerization

coordination polymerizationcoordination polymerization

Polymerization of AlkenesPolymerization of Alkenes

HH22SOSO44

++

monomermonomer(C(C44HH88))

two dimerstwo dimers(C(C88HH1616))

Dimerization of 2-methylpropeneDimerization of 2-methylpropene

(CH(CH33))22CC CHCH22

CHCH33CCHCCH

CHCH33

CHCH33

C(CHC(CH33))22 CHCH33CCHCCH22CC

CHCH33

CHCH33

CHCH22

CHCH33

Cationic PolymerizationCationic Polymerization

CHCH33CCHCCH22CC

CHCH33

CHCH33

CHCH33

CHCH33

++

++

CHCH33

HH22CC CC

CHCH33

CHCH33CC

CHCH33

++

CHCH33

Mechanism of DimerizationMechanism of Dimerization

++CHCH33CCHCCH

CHCH33

CHCH33

C(CHC(CH33))22 CHCH33CCHCCH22CC

CHCH33

CHCH33

CHCH22

CHCH33

CHCH33CCHCCH22CC

CHCH33

CHCH33

CHCH33

CHCH33

++

Mechanism of DimerizationMechanism of Dimerization

200 °C200 °C2000 atm2000 atm

OO22

peroxidesperoxides

polyethylenepolyethylene

HH22CC CHCH22

CHCH22 CHCH22 CHCH22 CHCH22 CHCH22 CHCH22 CHCH22

Free-Radical Polymerization of EthyleneFree-Radical Polymerization of Ethylene

••....

RORO....

HH22CC CHCH22

MechanismMechanism

HH22CC CHCH22••

....RORO::

MechanismMechanism

HH22CC CHCH22••

....RORO::

MechanismMechanism

CHCH22HH22CC

HH22CC CHCH22

HH22CC CHCH22••

....RORO::

MechanismMechanism

HH22CC CHCH22

HH22CC CHCH22••

....RORO::

MechanismMechanism

CHCH22HH22CC

HH22CC CHCH22

HH22CC CHCH22

•• HH22CC CHCH22

....RORO::

MechanismMechanism

HH22CC CHCH22

HH22CC CHCH22

•• HH22CC CHCH22

....RORO::

MechanismMechanism

CHCH22HH22CC

polypropylenepolypropylene

HH22CC CHCHCHCH33

CHCH CHCH CHCHCHCHCHCHCHCH CHCH

CHCH33 CHCH33 CHCH33 CHCH33 CHCH33 CHCH33 CHCH33

Free-Radical Polymerization of PropeneFree-Radical Polymerization of Propene

••....

RORO....

HH22CC CHCHCHCH33

MechanismMechanism

HH22CC CHCHCHCH33••

....RORO::

MechanismMechanism

HH22CC CHCHCHCH33••

....RORO::

MechanismMechanism

CHCHCHCH33HH22CC

HH22CC CHCHCHCH33

HH22CC CHCHCHCH33••

....RORO::

MechanismMechanism

HH22CC CHCHCHCH33

HH22CC CHCHCHCH33••

....RORO::

MechanismMechanism

CHCHCHCH33HH22CC

HH22CC CHCHCHCH33

HH22CC CHCHCHCH33

•• HH22CC CHCHCHCH33

....RORO::

MechanismMechanism

HH22CC CHCHCHCH33

HH22CC CHCHCHCH33

•• HH22CC CHCHCHCH33

....RORO::

MechanismMechanism

CHCHCHCH33HH22CC

HH22C=CHCl C=CHCl polyvinyl chloridepolyvinyl chlorideHH22C=CHCC=CHC66HH5 5 polystyrenepolystyreneFF22C=CFC=CF22 TeflonTeflon

Likewise...Likewise...