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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
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 LiouReporter : Tzu-Tien Huang
Date : 2014 / 12 / 26
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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 LiouReporter : Tzu-Tien Huang
Date : 2014 / 12 / 26
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Outline
Introduction
Motivation
Experiment
Result and Discussion
Summary
Polymerization of Divinylbenzene
Cross-linked or Star-branched
Polymer
Soluble Polymer Stable Living Polymer
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Polymerization of Divinylbenzene
Isomers
Crosslinked Polymer
Insoluble Polymer
Ion exchange resin
Column – Packing agents
Pendent vinyl group
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Cross-linked Polymer
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D. J. Worsfold, Macromolecules, 1970, 3, 514
Flory-Huggins Theory Gel Point
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L. J. Fetters, Macromolecules, 1978 11, 899
Star-branched PolymerPoly(isoprenyl) – lithium + m-divinylbenzene
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Growing carbanion ↑ → life time ↓ (Chain transfer by DPA) Reactivity Pendent vinyl groups < DVB monomerGrowing carbanion ↑ → Reactivity ↓(Stabilized 10 π -conjugation.)
Soluble Polymer
Teiji Tsuruta, J. MACROMOL. SCI.-CHEM., 1989, A26(8), 1043
Lithium diisopropylamide (LDA)
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Pendent vinyl groupContent
Charge Transfer (DPA)
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Stable Living Polymer
Akira Hirao, Macromolecules, 2011, 44, 4579
In THF at -78 for 1 ℃min
Initiator – Oligo ( α-methylstyryl ) lithium ( sec-BuLi / α-MeSt )Additive - KOBut
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Initiator sec-BuLi sec-BuLi/α-MeSt /KOBut
sec-BuLi/α-MeSt /KOBut
sec-BuLi/α-MeSt /KOBut
12 eq 12 eq 5 eq
DVB-5DVB-4DVB-3DVB-1
Anionic Polymerization of 1 in THF at 78 C for 1 min
SEC profiles of polymers
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Motivation
Soluble Polymer
High yield
High molecular weightSmall PDI
Stable Living Polymer
Polymerization of Divinylbenzene
Avoid Crossliked or gel(Pendent vinyl group reation)
Time vs TemperaturePendent vinyl group reactivity
Expected Polymerization
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Synthesis of 1,4-Divinylbenzene
(1)
106 g
THF
1500 ml
(2)
321 gN2
R.T.
stir 20 min
(3) or (4) or (5) / THF
59.6 g / 500 mlTemp ¡Õ 40¢J
R.T.
stir 1 hr
H2O / Ice Extraction (n-hexane)
Dry1200 ml / 800ml
Scheme
Procedure
CH3
OKH3CH3C
P+H3CBr-
O
O
HO
OH
O O
HO OH
O O
HO OH
THF, 40 ¢J
(8)
(7)
(6)
(5)
(4)
(3)
(2)(1)
Potassiumtert - butoixde
MethyltriphenylPhosphonium
Bromide
Phthaladehyde Divinylbenzene
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Preparation of Additives
R OH
Phenol or Alochol
0.3 M THF
Solution A Solution B
K
Potassium naphthalenide
0.5 ~ 0.8 M THF
THF at −78 ℃ Colorimetric
titration
0.05 ~ 0.1 MPotassium Alkoxides
and Phenoxides
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PolymerizationSurrounding - THF -78℃
THF -95 ℃
Initiator - Oligo ( α-methylstyryl ) lithium ( sec-BuLi / α-MeSt )
Additive - Potassium Alkoxides and Phenoxides
Monomer - 1,4 – Divinylbenzene
1,3 – Divinylbenzene
1,2 - Divinylbenzene
Terminator - Methanol
N2
N2
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Result and Discussion
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Previous - KOBut
Akira Hirao, Macromolecules, 2011, 44, 4579
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-5DVB-4DVB-3DVB-1
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Effect of Metal Alkoxides - Metal
x
[Initiator] = 2~3 ×10-3 M ; [Monomer] = 0.2~0.9 M
LiOBut NaOBut KOBut
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Effect of Potassium AlkoxidesReacting alcohol with potassium naphthalenide in THF at −78 (10 eq)℃
CR
R
OR
OR
Acetal Oxygen Atom
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Effect of Potassium AlkoxidesReacting alcohol with potassium naphthalenide in THF at −78 (10 eq)℃
Less of steric hindrance
pKa small
→ The ion is stable
→ Ion-dissociated > Ion-pair
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Effect of Potassium Phenoxides and Potassium Pivalate Potassium Phenoxides Potassium Pivalate
Phenol pKa=10 < Alcohol pKa=16~18
Pivalic acid
pKa= 5 → 70%PDI = 1.04
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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
Soluble Polmer
Small PDI
Potassium Alkoxides
Potassium Phenoxides
Potassium Salt
(Pivalic acid)
Reacting in THF at −78 ℃
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
Not Absolutely
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Effect of Temperature and Polymerization Time In THF at −78 for 5 min ℃
Mn ↑ PDI↑
In THF at −95 for 10~30 ℃min
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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1,4 - Divinylbenzene
1,2 - Divinylbenzene
1,3 - Divinylbenzene
Anionic Polymerization of Divinylbenzenes Isomers
10 π, 5 resonace
10 π, 5 resonace
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
1,1-diphenylethylene
tert-butyl methacrylate-78 for 3hr (enolate anion)℃
-78 for 5hr℃ (diphenyl)
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Soluble Polymer Small PDI High Yield Stable Living
Polymer 30
Additive
Reaction Time and Temperature
Potassium Alkoxides
Potassium Phenoxides
Potassium Salt
(Pivalic acid)
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
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Thank you for your attention !