Titanium trichloride catalyst

Propylene Polymerization Kinetics in Gas Phase Reactors Usii Titanium Trichloride Catalyst... 

This assumption is confirmed by the fact that adding titanium tetrachloride to a-titanium trichloride catalysts a greater contamination in the reaction products with labeled ethylaluminum is obtained (4 ). 

Boor (65) showed that the specificity and activity of a propylene catalyst depended on both catalyst components. The addition of tri-alkylamines to titanium trichloride catalysts made with diethylzinc, ethylzinc chloride, or diethylcadmium, increased the specificity of the catalyst. There was also a simultaneous decrease in activity. Boor ascribed this phenomena to the amine deactivating catalysts which cause the non-stereospecific polymerization. The amine either destroyed the... 

Ashikari, Kanemitsu, Yanagisawa, Nakagawa, Okomoto, Ko-bayashi and Nishioko (59) have studied the copolymerization of propylene and styrene. They found decreasing styrene content and conversion of the copolymer by increasing aluminum to titanium ratios with triisobutyl aluminum and titanium trichloride catalysts. The trialkylaluminum titanium tetrachloride catalyst had relatively low steric control on the polymerization while trialkylaluminum-titanium trichloride had higher steric control. The ionicity which is required for atactic polymerization is more cationic for styrene than for propylene which is more cationic than that for ethylene. Some of the catalyst systems for these three monomers are shown on the ionicity chart in Fig. 9. 

Natta (119) has made an excellent summary of the catalysts which produced various structures of polybutadiene. The more acidic vanadium and titanium trichloride catalysts produced large amounts of trans 1.4-polymer. Less acidic titanium iodide, cobalt, and nickel catalysts produced high amounts of cis 1.4 structure (Table 9). 

PP is produced by a variety of processes, most of them by a diluent phase propylene polymerization utihzing a Ziegler-Natta-activated titanium trichloride catalyst in the presence of low- to high-boiling hydrocarbons. Residual catalyst removal followed by hydrocarbon slurry centrifugation is the immediate upstream operation prior to thermal drying. Hexane is the solvent used in the major PP processes in operation today. As a result these polymers are solvent wet. 

PP is produced by a variety of processes, most of them by a diluent phase propylene polymerization utilizing a Ziegler-Natta-activated titanium trichloride catalyst in the presence of low- to high-boiling hydrocarbons. 

Solvay has been pionnering high performance titanium trichloride catalyst since 1970. In 1977, this work led to the first definite Jump in industrial PP catalyst performance through the commercial production of the second generation catalyst affording both higher productivity and stereospecificity. The continuous research effort to improve and extend the catalyst properties has now led to the new SB 12, third generation 11013. product embodies the latest development in the field and... 

The accessible product range is also broadened thanks to the exceptional intrinsic stereospecificity and molecular veight control of the catalytic system. High quality and consistency are favoured by easy and smooth control of the polymerization conditions due to the catalyst properties. In addition, future progress can be foreseen as a result of specialized development studies of this type of titanium trichloride catalyst currently under way. 

The most widely used transition metal salts have been the relatively cheap titanium or vanadium halides, reduced with aluminum alkyls. In Ziegler s work, titanium tetrachloride was reduced to brown yS-titanium trichloride, which was able to polymerize ethylene. However, when yS-titanium trichloride catalyst was used in the polymerization of propylene, the product contained a high proportion of the gum like atactic polymer, which was not viable for commercial use. In contrast, Natta, in his work on the polymerization of propylene and other a-olefins, showed that violet a-titanium trichloride could polymerize propylene to the useful, crystalline, isotactic polymer. Nevertheless, a relatively large quantity of atactic polypropylene still had to be separated from the commercial isotactic product. 

Catalytic activity can be considerably increased if the magnesium chloride is first combined with a suitable Lewis base, such as an ester, acid, alcohol, or amine, before reaction with an excess of titanium tetrachloride and subsequent activation with triethyl aluminum. Polyethylene produced with these catalysts has a lower molecular weight than that from the titanium trichloride catalysts mentioned earlier and less hydrogen is needed for molecular weight control. 

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