Olefins technology development

Ethylene-cyclo-olefin copolymers have been known since 1954 (DuPont USP2 721 189) but these materials only became of importance in the late 1990s with the development of copolymers of ethylene and 2-norbomene by Hoechst and Mitsui using metallocene technology developed by Hoechst. The product is marketed as Topas by Ticona. By adjustment of the monomer ratios polymers with a wide range of Tg values may be obtained including materials that are of potential interest as thermoplastic elastomers. This section considers only thermoplastic materials, cyclo-olefins of interest as elastomers are considered further in Section 11.10. 

DeFine a process technology developed by UOP Corporation for reducing the level of dienes in an olefin stream EO ethylene oxide... 

The other possibility is to coat the silica with a polymer of defined properties (molecular weight and distribntion) and olefin groups, e.g., polybutadiene, and cross-linked either by radiation or with a radical starter dissolved in the polymer [32]. This method is preferentially used when other carriers like titania and zirconia have to be surface modified. Polyethylenimine has been cross-linked at the snrface with pentaerythrolglycidether [41] to yield phases for protein and peptide chromatography. Polysiloxanes can be thermally bonded to the silica surface. Other technologies developed in coating fnsed silica capillaries in GC (polysiloxanes with SiH bonds) can also be applied to prepare RP for HPLC. 

Finally, in the fourth section the fundamentals of the modelling concerning two basic olefin polymerization processes are examined heterogeneous slurry polymerization and gas-phase polymerization. The SPERIPOL process for making High Impact PolyPropylene (HIPP) is then described as an illustrative example for combining fundamentals and elements of product and technology development. 

To meet the challenge of changing olefins technology, future pyrolysis modeling will move toward a more mechanistic framework. The rate of this development will be controlled by the advances made in kinetic theory and by the speed of... 

This approach is shown in the synthesis of progesterone (202) in Scheme 10.17. 21 A Wittig olefination 22 (sec. 8.8.A) coupled 197 with 198. The improved technology developed for the cyclization led... 

The outstandingly rapid scientific and technological development of metallocene-based catalysts for olefin polymerization is a perfect example of the successful application of organometallic chemistry to homogeneous catalysis and of the teaching that understanding reactions at the molecular level can provide to the more matter-of-fact fields of heterogeneous ca-... 

Olefins Conversion Technology [OCT] A process for converting mixtures of ethylene and butenes to propylene by metathesis (disproportionation). Based on technology developed by Phillips Petroleum in the... 

However, even with technological development, there still exist some significant limitations in vinyl polymerization as a method for polymer synthesis. For example, because of the significant difference of reactivity between non-polar olefins (ethylene, propylene, etc.) and polar monomers (e.g., alkyl [meth]acrylate), random copolymerization of such a monomer combination as ethylene and alkyl acrylate... 

The first commercial process for making LLDPE was the Sclair technology developed by Dupont Canada and now implemented by NOVA Chemicals. This process involves high-temperature solution polymerization. Much LLDPE is now made in gas-phase reactors with butene or hexene as the co-monomer. The constrained-geometry catalyst (CGC) is a metallocene catalyst developed by Dow Chemical for the manufacture of linear, very-low density polyethylene resins by solution polymerization with octene as the comonomer. For a given co-monomer content, the solid-state density is lower for octene than for lower a-olefins. 

An independent development of a high pressure polymerization technology has led to the use of molten polymer as a medium for catalytic ethylene polymerization. Some reactors previously used for free-radical ethylene polymerization at a high pressure (see Olefin polymers, low density polyethylene) have been converted to accommodate catalytic polymerization, both stirred-tank and tubular autoclaves operating at 30—200 MPa (4,500—30,000 psig) and 170—350°C (57,83,84). CdF Chimie uses a three-zone high pressure autoclave at zone temperatures of 215, 250, and 260°C (85). Residence times in all these reactors are short, typically less than one minute. 

Linear a-olefins were produced by wax cracking from about 1962 to about 1985, and were first commercially produced from ethylene in 1965. More recent developments have been the recovery of pentene and hexene from gasoline fractions (1994) and a revival of an older technology, the production of higher carbon-number olefins from fatty alcohols. 

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