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1
ZIEGLER-NATTA CATALYST
PRESENTED BY:
LISAMONI KALITA
M.SC 2ND SEM
ID: BS14MC0229
DEPT. OF CHEMISTRY
ASSAM KAZIRANGA UNIVERSITY
2Table of Contents
Introduction
Brief History of Ziegler Natta Catalyst
Mechanism of Ziegler Natta Polymerization
Importance of Ziegler Natta Catalyst
Applications of Ziegler Natta Catalyst
Conclusion
Reference
3Introduction
Karl Ziegler in 1953 polymerized ethylene catalytically to polyethylene. Giulio Natta utilized Ziegler's catalyst to produce polypropylene in 1954. In 1963, both Karl Ziegler and Giulio Natta were awarded the Nobel Prize for their discoveries.
In 1973 the 2nd generation Ziegler-Natta catalysts were introduced with β-TiCl3 at lower
temperatures.
In 1980 3rd generation catalysts supported on MgCl2 were commercialized by many
companies. In 1991 4th generation Ziegler-Natta catalysts based on aluminoxane activated metallocene
complexes were used. Two broad classes:
Heterogeneous Catalyst: Based on Ti compounds Homogeneous Catalyst: Based on complexes of Ti, Zr and Hf
4Ziegler’s Discovery (Germany,1953)
Co-catalyst catalyst
Karl Ziegler-the last Al-Chemist “...because he turned aluminium into gold.”
TiCl4 1 atm20-70 C
Al(Et)3 + CH2CH2"linear"
Mw = 10,000 - 20,00,000
5Natta’s Discovery (Italy,1954)
isotactic
syndiotactic
CH3
VCl4Al(iBu)2Cl
- 78 CCH3CH3 CH3
CH3CH3 CH3
CH3TiCl3
Al(Et)2Cl
6Mechanism of Ziegler-Natta Polymerization: The Cossee Mechanism
Ti CH2CH3
Ti CH2CH3
CH2H2C
Ti
CH2
Polymer
Catalyst acceptsethylene as a ligand
1,2- Migratory insertion [Ethyl migration]
Ti CH2CH3
H2C CH2
ligandassociation
Ti CH2CH2
CH2H2C
7
Termination Step: Chain Transfer
Ti
CH2
Polymer
Ti HTi
CH2CH3
Ti H
H2PolymerH+
8Kaminsky Catalyst System
M = Ti, Zr, Hf
Linear
Atactic polypropylene
M
X
X
+ Al O
CH3
n
M
X
X
+ Al O
CH3
n
CH3
MAO
MAO
MAO=methylaluminoxane
Homogeneous Ziegler Natta Catalyst
9Brintzinger System
Brintzinger developed these catalysts which when activated with MAO catalysed the stereoselective polymerizations of propylene with very high activities. Thus for the first time isotactic polyolefins were obtained using homogeneous Ziegler-Natta catalyst
Si
R
R
MX
X
ansa-metallocene
R= CH3, C2H5
X= Cl, Br, CH3
M= Ti, Zr
10Importance of Ziegler Natta Catalyst High Selectivity
High Efficiency
High Stereoregularity (99% tacticity)
Longer Lifetime
High concentration of polymer product
Lower cost in production
Easy regeneration of catalyst
Controls growth and formation of polymer product
Control of polymer particle morphology in spherical shape
Higher stability
11Example:
Propene can polymerize in three ways:
TiCl4 + Al(C2H5)3
CH3
Highly selective towards isotactic productHighly stable product
CH3CH3 CH3 CH3 CH3 CH3CH3 CH3 CH3 CH3
CH3CH3 CH3 CH3 CH3
CH3CH3 CH3 CH3 CH3
Atactic Isotactic Syndiotactic
MgCl2
12
Applications of Ziegler-Natta CatalystProduction of:
High density polyethylene (HDPE)
Linear low density polyethylene (LDPE)
Ultra-high molecular weight polyethylene (UHMWPE)
Thermoplastic polyolefins (TPO’s)
Polybutylene (PB)
Shiny lustrous polyacetylene film which have semiconducting properties
Crystalline polypropylene
Carbon nanotubes nanocomposites
13
14Conclusion
Ziegler Natta are mainly used to polymerize 1-alkenes.
Ziegler Natta catalyst is composed of a catalyst and co-catalyst.
Ziegler-Natta catalysts can be categorized into heterogeneous and homogenous by their form in catalysis process. The heterogeneous one is widely used in industry.
Only Ziegler-Natta catalysts can produce highly stereoregular and linear unbranched polyolefins.
15References Pokasermsong P. and Praserthdam P.; Comparison of Activity Of Ziegler-Natta
Catalysts; Engineering Journal; Vol. 13; 2009; 57
Ahmad A.; Propylene Polymerization Using 4th Generation Ziegler-Natta Catalysts:
Polymerization Kinetics and Polymer Microstructural Investigation; A thesis
presented to the University of Waterloo; 2011
Cerruti L.; Historical and Philosophical Remarks on Ziegler-Natta Catalysts; HYLE –
An International Journal for the Philosophy of Chemistry; Vol. 5; 1999; 3.
Bajgur C. S. and Sivaram S.; The evolution of new generation ‘single-site’ Ziegler–
Natta polymerization catalysts; Current Science; Vol. 78; 2000; 1325
Busico V., Cipullo R., Pellecchia R., Ronca S., Roviello G., and Talarico G.; Design of
stereoselective Ziegler–Natta propene polymerization catalysts; PNAS; vol. 103;
2006; 15321
16References Contd. Lewin M.; Handbook of Fiber Chemistry; CRC Press; Third Edition; ISBN 1420015273
Gross E., Liu J. H, Toste F. D. and Somorjai G. A.; Control of selectivity in heterogeneous
catalysis by tuning nanoparticle properties and reactor residence time; Nature
Chemistry ; Vol. 4; 2012; 947
Clayden J., Greeves N. and Warren S.; Organic Chemistry; Oxford; Second Edition; ISBN
978-0-19-927029-3
Gupta B. D., Elias A. J.; Basic Organometallic Chemistry Concepts, Syntheses and
Applications; University Press; Second Edition; ISBN 978-81-7371-874-8
Ramakrishnan S; Conducting Polymers; RESONANCE ; Vol.2; 2011; 48
http://en.wikipedia.org/wiki/Ziegler%E2%93Natta_catalyst
http://www.chemheritage.org/discover/online-resources/chemistry-in-history/themes/
petrochemistry-and-synthetic-polymers/ziegler-and-natta.aspx
17
THANK YOU
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