103 學年度台灣大學高分子科學與工程學系
高分子合成特論
Living Anionic Polymerization of
1,4-Divinylbenzene and Its Isomers
Shunsuke Tanaka, Masayoshi Matsumoto, Raita Goseki, Takashi Ishizone, and Akira Hirao,
Macromolecules, 2013, 46, 146
Advisor : Professor Guey-Sheng Liou
Reporter : Tzu-Tien Huang
Date : 2014 / 12 / 26
1
103 學年度台灣大學高分子科學與工程學系
高分子合成特論
Advisor : Professor Guey-Sheng Liou
Reporter : Tzu-Tien Huang
Date : 2014 / 12 / 26
2
Outline
Introduction
Motivation
Polymerization of
Divinylbenzene
Cross-linked or
Star-branched
Polymer
Soluble Polymer
Stable Living
Polymer
Experiment
Result and
Discussion
Summary
3
Introduction
4
Polymerization of Divinylbenzene
Isomers
Crosslinked Polymer
Insoluble Polymer
Ion exchange resin
Column – Packing agents
Pendent vinyl
group
5
Cross-linked Polymer
Flory-Huggins Theory
Gel Point
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D. J. Worsfold, Macromolecules, 1970, 3, 514
Star-branched Polymer
Poly(isoprenyl) – lithium + m-divinylbenzene
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L. J. Fetters, Macromolecules, 1978 11, 899
Soluble Polymer
Lithium diisopropylamide (LDA)
Growing carbanion ↑ → life time ↓
(Chain transfer by DPA)
 Reactivity
Pendent vinyl groups ＜ DVB monomer
Growing carbanion ↑ → Reactivity ↓
(Stabilized 10 π -conjugation.)
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Teiji Tsuruta, J. MACROMOL. SCI.-CHEM., 1989, A26(8), 1043
Pendent vinyl groupContent
Charge Transfer (DPA)
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Stable Living Polymer
In THF at -78 ℃ for 1 min
Initiator – Oligo ( α-methylstyryl ) lithium
( sec-BuLi / α-MeSt )
Additive - KOBut
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Akira Hirao, Macromolecules, 2011, 44, 4579
Anionic Polymerization of 1 in THF at 78 C for 1 min
SEC profiles of polymers
DVB-1
Initiator
sec-BuLi
DVB-3
DVB-4
DVB-5
sec-BuLi/α-MeSt
/KOBut
sec-BuLi/α-MeSt
/KOBut
sec-BuLi/α-MeSt
/KOBut
12 eq
12 eq
5 eq
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Motivation
Polymerization of Divinylbenzene
Soluble
Polymer
Expected Polymerization
Stable Living
Polymer
Avoid Crossliked or gel
(Pendent vinyl group reation)
High yield
Pendent vinyl group
reactivity
Time vs Temperature
Small PDI
High molecular
weight
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Experiment
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Synthesis of 1,4-Divinylbenzene
Scheme
O
OH
HO
CH3
H3C
OK
H3C
Potassium
tert - butoixde
H3C
Br-
O
O
P+
O
HO
(4)
O
THF, 40 ¢J
O
HO
(2)
(1)
(7)
OH
Methyltriphenyl
Phosphonium
Bromide
(6)
(3)
OH
(5)
(8)
Divinylbenzene
Phthaladehyde
Procedure
N2
(1)
THF
(2)
R.T.
(3) or (4) or (5) / THF
106 g
1500 ml
321 g
stir 20 min
59.6 g / 500 ml
Temp ¡Õ 40¢J
R.T.
stir 1 hr
H2O / Ice
Extraction (n-hexane)
1200 ml / 800ml
Dry
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Preparation of Additives
Solution B
Solution A
R OH
Phenol or Alochol
K
THF at −78 ℃
Colorimetric
titration
Potassium naphthalenide
0.5 ~ 0.8 M THF
0.3 M THF
0.05 ~ 0.1 M
Potassium Alkoxides
and Phenoxides
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Polymerization
Surrounding - THF -78℃
THF -95 ℃
Initiator - Oligo ( α-methylstyryl ) lithium ( sec-BuLi / α-MeSt )
N2
Additive - Potassium Alkoxides and Phenoxides
N2
Monomer - 1,4 – Divinylbenzene
1,3 – Divinylbenzene
1,2 - Divinylbenzene
Terminator - Methanol
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Result and Discussion
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Previous - KOBut
Atom size : K+ ＞Li+
Salt effect > Solvation (Abound of K+ )
( ion-pair > ion-dissociated )
Steric bulkiness (tert-Butyl)
Main Chain ↑ → Pendant vinyl group reativity ↓
(The vinyl group of main chain is electron donating)
DVB-1
DVB-3
DVB-4
DVB-5
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Akira Hirao, Macromolecules, 2011, 44, 4579
Effect of Metal Alkoxides - Metal
[Initiator] = 2~3 ×10-3 M ; [Monomer] = 0.2~0.9 M
LiOBut
NaOBut
KOBut
x
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Effect of Potassium Alkoxides
Reacting alcohol with potassium naphthalenide in THF at −78 ℃ (10 eq)
Acetal Oxygen Atom
R
OR
C
R
OR
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Effect of Potassium Alkoxides
Reacting alcohol with potassium naphthalenide in THF at −78 ℃ (10 eq)
pKa small
→ The ion is stable
→ Ion-dissociated > Ion-pair
Less of steric hindrance
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Effect of Potassium Phenoxides and
Potassium Pivalate
Potassium Phenoxides
Potassium Pivalate
Pivalic acid
pKa= 5 → 70%
PDI = 1.04
Phenol pKa=10 < Alcohol pKa=16~18
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Effect of 18-Crown-6, and P4-tBu
18-Crown-6
P4-tBu
Strongly coordinate with K+
Steric bulkiness
Soluble polymer but PDI large
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Summary of Additive
Steric bulkiness
Increase the distance between chain end anion and pendent vinyl group.
Basicity
Effect the ion stability
(Compare the Interaction between Ion-dissociated and ion-pair
Reacting in THF at −78 ℃
Potassium
Alkoxides
Not Absolutely
Soluble Polmer
Small PDI
Potassium
Salt
(Pivalic acid)
Potassium
Phenoxides
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Effect of Temperature and
Polymerization Time
In THF at −78 ℃ for 5 min
Mn ↑
In THF at −95 ℃ for 10~30 min
PDI↑
30 min
10 min
15 min
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Anionic Polymerization of 1,2- and
1,3-Divinylbenzenes
1,2 - Divinylbenzene
1,3 - Divinylbenzene
Bulky group protect ↓
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Anionic Polymerization of
Divinylbenzenes Isomers
1,4 - Divinylbenzene
10 π, 5 resonace
1,2 - Divinylbenzene
10 π, 5 resonace
1,3 - Divinylbenzene
8 π, 4 resonace
1,4 and 1,2 - Divinylbenzene is more stable than 1,3 - Divinylbenzene
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Stabilization of Chain-End Anion
tert-butyl methacrylate
1,1-diphenylethylene
-78 ℃ for 3hr (enolate anion)
-78 ℃ for 5hr (diphenyl)
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Summary
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Additive
Potassium Alkoxides
Potassium Phenoxides
Potassium Salt
(Pivalic acid)
Reaction Time and Temperature
In THF at −78 ℃ for 1 min
In THF at −95 ℃ for 10~30 min
Divinylbenzenes Isomers
1,4 and 1,2 - Divinylbenzene is more stable than 1,3 - Divinylbenzene
Stabilization of Chain-End Anion
tert-butyl methacrylate
1,1-diphenylethylene
Soluble
Polymer
Small PDI
High Yield
Stable Living
Polymer
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Thank you for your attention !
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