Aluminum alkyl halogenides

The Ziegler-Natta catalysts are metal-organic mixed catalysts. These catalysts result from mixing compounds of the metals of the secondary groups IV-VIII with metal alkyls or hybrids of groups I-III in the periodic table. Combinations of TiCL, TiCls, or VOCI3 with aluminum alkyls or aluminum alkyl halogenides are... 

Next to isobutene, other 1,1-dialkyl substituted ethenes can also be polymerized cationically. Suitable monomers are 2-methyl-1-butene, 2-methyl-1-pentene, and 2,3-dimethyl-1-butene [613] Polymers with very high molecular weights of Mn>300000 are obtained by catalysis with aluminum alkyl halogenides. Also, cyclic hydrocarbons with a methylene group (methylenecyclopropane, methylene cyclobutane, methylene cyclohexane, a-pinene) are suitable monomers [614-619]. 1,1-Disubstituted ethenes with stronger steric hindrance as camphene or 2-methylene-bicyclo-[2.2.1] heptane, however, could not be polymerized cationically [574]. 

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