8 Lewis Acid−Base Pairs for Polymerization Catalysis …
301
Initiation
LB
O
O
Me
[Al]
Deprotonation
O
O [Al]
[H-LB]
Propagation
O
O
O
O
n
O
O
Chain transfer
O
O
O
n
O
O
O
O
[Al]
Catalyst recapture
O
O
O
[Al]
O
O
[Al]
O
O
O
O
n
O
O
[Al] [H-LB]
[Al]
[H-LB]
+
H
(n+1)
c
+
O
O [Al]
O
O
O
O [Al]
[Al]
Chain transfer
to monomer
O
O
O
O
O
O
O
O
[Al]
O
O
[Al]
O
O
O
O
[Al]
[Al]
H-shuttling
chain transfer
O
O
O
O
O
O
Et
3 N
[Et
3 N-H]
[Et
3 N-H]
[Et
3 N-H]
H
O
O
O
O
O
O
O
O
n
CLA
FLP
Acrylic
Bioplastic
Dimerization
Polymerization
H
2
Biofuel
-AL
Dimer
b
a
O
O
[Al]
H
+
Et
3 N
O
O
[Al]
H
Scheme 8.12
LP-mediated selective dimerization and polymerization of
β-AL to biofuel and acrylic bioplastic (a); proposed mechanistic scenario of
β-AL
polymerization by MeAl(BHT)
2 /I i
Pr CLA (b); and
β-AL dimerization by MeAl(BHT)
2 /Et
3 N FLP (c)