Ziegler first generation

TiCl3 catalysts for 1-butene polymerization have relatively low activity.883 The old Shell process made use of a first-generation Ziegler-Natta catalyst, and required de-ashing of the final polymer. The new Basell process makes use of a much improved high yield MgCl2-supported Ti-based ZN catalyst and a two-reactor setup. Improved... 

Ziegler catalysts studied for the oligomerisation of a-olefins tend to be based on modified first-generation catalysts, i.e. triethylaluminium/titanium tetrachloride. The aluminium/fitanium ratio has a marked effect on product properties, at less than 0.8 1, liquids were produced, whereas at ratios above 1 1, waxy products were obtained [6, 7]. This effect is believed to relate to changes in the catalysis mechanism, from cationic to anionic with higher proportions of aluminium. 

The first generation of catalysts based on titanium tetrachloride or different modifications of titanium trichloride and ethyl-, isobutyl-, isoprenyl-, or chloride containing aluminum compounds, Ziegler catalysts, (Table 1) was characterized by low polymerization activity. Kinetic studies and applications of various methods have helped to define the nature of the active center . ... 

Table I. Selected First-Generation Ziegler-Natta Catalysts...

The majority of the research summarized in this chapter will pertain to second-generation, magnesium-containing Ziegler catalysts due to their importance to the polyethylene industry today. However, a brief summary of first generation catalysts will be included due to the historical importance of these early ethylene polymerization catalysts from an academic and industrial perspective (see Appendix 2.1 for review references on first generation Ziegler catalysts). 

First Generation Ziegler Catalysts for the Manufacture of Polyethylene... 

The activity of these second generation Ziegler catalysts is 10-100 times more active on a titanium basis than the first-generation Ziegler catalysts, which created significant growth opportxmities in the polyethylene industry. 

Review References for First Generation Ziegler Catalysts... 

Soon after the discovery of the first generation Ziegler catalysts and the chromium-based Phillips catalysts in the mid-1950s, the need developed... 

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