First Ziegler Catalyst Commercial Process

The Ziegler process for the manufacture of polyethylene followed a route similar to the Phillips process. According to Sailors and Hogan [21], the first 

Ziegler licensed the catalyst technology worldwide starting in 1954. The license included use of Ziegler s patent and a 100 page manual describing a laboratory process. Early licensees are summarized in Table 5.18. 

National Petro Chemicals - Deer Park, Texas 

Union Carbide Plastics - Port Lavaca, Texas 

Because licensees of the Ziegler catalyst developed their own proprietary process technology, DuPont Sclair provides an excellent example how a Ziegler licensee developed and expanded both the process, catalyst and product technology, developing new markets and applications for low-pressure polyethylene. 

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Polymerization in a hydrocarbon slurry (usually a light-saturated hydrocarbon) was the first commercial polymerization process to utilize Phillips and Ziegler catalysts. These processes enjoy high popularity because of theit versatihty. 

Propylene polymerization processes have undergone a number of revolutionary changes since the first processes for the production of crystalline polypropylene (PP) were commercialized in 1957 by Montecatini in Italy and Hercules in the United States. These first processes were based on Natta s discovery in 1954 that a Ziegler catalyst could be used to produce highly isotactic polypropylene. The stereoregular, crystalline polymers produced by this technology had sufficiently attractive economic and property performance that they became significant commercial thermoplastics in a remarkably short period. 

As previously stated, the first polymerization catalysts described by Ziegler consisted of mixtures of TiCU and aluminum trialkyls, which reacted with each other continuously to give TiCls and aluminum alkyl chlorides. However, in much recent research work, and in many commercial systems where titanium chlorides are employed, a preformed suspension of TiCls crystals is prepared separately and added to the reaction vessel. There are four reasons for selecting processes of this type ... 

ATOL [Atochem polymerization] A gas-phase process for making polyethylene. Developed by Atochem and first commercialized in 1991. It uses a Ziegler-Natta catalyst containing titanium and magnesium halides. First commercialized at Gonfreville, France, in 1991. 

Borstar A catalytic process for polymerizing ethylene. Use of two reactors, a loop reactor and a gas-phase reactor, allows better control of molecular weight distribution. The loop reactor operates under super-critical conditions to avoid bubble formation. Either Ziegler-Natta or metallocene catalysts can be used. The first commercial unit was installed in Porvoo, Finland, in 1995. 

Catalloy A gas-phase process for making olefin co-polymers, using Ziegler-Natta catalysts. It uses a series of three gas-phase reactors to which monomer is progressively added. The properties of the product can be varied according to the monomer grades used. Developed by Himont and first commercialized in 1990. Now operated by a joint venture of Montell Polyolefins and Japan Polyolefins. See also Hivalloy. 

Sclairtech An advanced version of the Sclair ethylene polymerization process, using a Ziegler-Natta catalyst and multiple reactors. Announced in 1996. The first commercial plant will be built in Alberta by Amoco Canada and Nova, and is scheduled for completion in 2000. 

UNIPOL [Union Carbide Polymerization] A process for polymerizing ethylene to polyethylene, and propylene to polypropylene. It is a low-pressure, gas-phase, fluidized-bed process, in contrast to the Ziegler-Natta process, which is conducted in the liquid phase. The catalyst powder is continuously added to the bed and the granular product is continuously withdrawn. A co-monomer such as 1-butene is normally used. The polyethylene process was developed by F. J. Karol and his colleagues at Union Carbide Corporation the polypropylene process was developed jointly with the Shell Chemical Company. The development of the ethylene process started in the mid 1960s, the propylene process was first commercialized in 1983. It is currently used under license by 75 producers in 26 countries, in a total of 96 reactors with a combined capacity of over 12 million tonnes/y. It is now available through Univation, the joint licensing subsidiary of Union Carbide and Exxon Chemical. A supported metallocene catalyst is used today. 

Borstar A catalytic process for polymerizing ethylene or propylene, subdivided into Borstar PE and Borstar PP. Use of two reactors — a loop reactor and a gas-phase reactor — allows better control of molecular weight distribution. The loop reactor operates under supercritical conditions to avoid bubble formation. Either Ziegler-Natta or metallocene catalysts can be used. The latest version, Borstar PE 2G, uses a single, multizone gas-phase reactor to make polymers that have bimodal molecular weight distributions. Developed by Borealis A/S. The first commercial unit, for polyethylene, was installed in Porvoo, Finland, in 1995. The first polypropylene plant was operated by Borealis in Schwechat, Austria, in 2000. In 2005, Borstar s total capacity for PE and PP was 1.3 million tons. 

Polypropylene was first polymerized in 1954 from propylene gas using Ziegler-Natta catalysts. Polypropylene is made commercially using the suspension process at around 60°C and conversions of 80-85 per cent from monomer to polymer are achieved (Brydson, 1999). The reaction mixture is centrifuged to recover solvent and unreacted catalyst. The polymer is washed and dried at 80°C prior to blending it with antioxidants and extruding it into pellets. 

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