HANOI UNIVERSITY OF MINING AND GEOLOGY
Faculty of Oil and Gas
Department of Oil Refining and Petrochemistry


POLYMERIZATION CATALYST

Presented By: Chu Việt Hùng CTTT 102 101 06
Nguyễn Anh Tuấn CTTT 102 101 21
Mai Ngọc Anh CTTT 102 101 24

Advanced Program – Course I – Faculty of Oil and Gas

Instructor : A.Prof. Phạm Xuân Núi

Ha Noi, May 29th, 2013

CONTENT
Polymerization catalysis…………………………………3
Situation ………………………………………………...3
Olefin polymerization ………………………..………….5
Catalytic polymerization in aqueous medium………….5
1. General introduction……………………………………..5
Ring-opening olefin metathesis polymerization………..8
Introduction……………………………………………...8
Catalysts………………………………………………..10
3. Aqueous polymerization with class 3 catalysts…………..14
3.1. Mechanism………………………………………....14
3.2. Polymers……………………………………………17
4. Aqueous polymerization with class 4 catalysts…………..19
4.1. Catalysts……………………………………………19
4.2. Polymers………………………………………….....22
4.2.1. Polymerization of water soluble monomers…….22
4.2.2. Polymerization of water insoluble monomers…..23
CONCLUSIONS……………………………………………..25
REFERENCES………………………………………….…...26
I. Polymerization catalysis
1. Situation
Classical polymers such as polyethylene, polypropylene, and polystyrene are again of great interest for science and industry. These polymers are not only the most extensively used plastics but they show an above-average growth rate as materials. This increase is caused largely by new catalysts which are able to tailor the polymer structure and, by this, the physical properties. Some recent reviews give detailed information on olefin catalysis, now one of the largest fields in chemistry.


Table 1: Worldwide production of polyolefins (x106 t)
In 1995, 53.6 x 106 t of polyolefins were produced worldwide. This amount makes up 47% of the entire production of plastics (Table 1).
Furthermore, in the past the extent of production of individual types such as LLDPE (linear low density polyethylene) or PP doubled in a period of about 5–7 years; this is an outstanding growth rate when compared to that of other materials. Estimates show that this development will continue. In the year 2005, the proportion of polyolefins will climb to 55%, taking into account a simultaneous increase in the entire production of plastics. In turn, this means that polyolefins will displace some of the commercial plastics of to day that are less easy to manufacture or pose more problems for recycling or waste disposal.
Polyolefins are composed solely of carbon and hydrogen. Being thermoplastics, they can be easily processed; used polyolefin materials can be recycled or combusted with a gain in energy, the only products being merely carbon dioxide and water. The basic units ethene and propene are easily obtained from the cracking of mineral oil. Apart from LDPE discovered by ICI, which has a highly branched structure and is produced radically at ethene pressures of 1000–3000 bar, polyolefins are synthesized at far lower pressures using catalysts.
The discovery of the catalyst based on titanium tetrachloride and diethylaluminum chloride as cocatalyst was made by Karl Ziegler, who succeeded in polymerizing ethene into HDPE (high density polyethylene) at standard pressure and room temperature in 1953 at the Max-Planck-Institute in Mülheim. A little later, Giulio Natta, at the Polytechnical Institute of Milan, was able to demonstrate that an appropriate catalyst system was capable of polymerizing propene into semi-crystalline polypropylene. Ziegler and Natta shared a Nobel Prize for Chemistry in 1963 for their work. The modern Ziegler–Natta catalysts are mixtures of solid and liquid compounds, often containing MgCl2/TiCl4/Al(C2H5)3 and, for propene polymerization, different internal and external donors such as ethylbenzoate, silanes or ethers to increase the tacticity.
Important for ethylene polymerization is the Phillips catalyst prepared by chromium trioxide on silica and reduced by hydrogen. This catalyst is very stable and useful in gas-phase polymerization but unable to polymerize propene to isotactic polymers.
Natta perceived that propene and long-chain olefins can be assembled in a stereoregular manner, the building blocks of the resulting chain having a defined and recurring arrangement. This alignment has a considerable influence on the functional properties of the material. A statistical arrangement leads to amorphous polypropylene which flows at room temperature, whereas stereoregular polypropylene is crystalline having a melting point of 165oC.
As Ziegler–Natta catalysts are heterogeneous and complex systems with different active sites, the polymer structure can be influenced only to a limited degree.
2. Olefin polymerization
Based on production data for 1999 and 2000, 85 –95 million tons of polyolefins (essentially homopolymers and copolymers of propylene and ethylene) are produced around the world. The worldwide polypropylene capacity is approximately 34 million tons, all of which is made with supported catalysts. Sixty percent of the remaining polyethylene is made on supported catalysts, bringing the current market for polyolefins produced on supported catalysts to a total of 65 –70 millions tons per year.
Olefin polymerization is also a highly exothermic reaction, with heats of polymerization in the order of 100 kJ/mol. Consequently, the heat