Initiation by metals or metal-containing

Finally, concurrently with addition, reduction of tri- or dihalomethyl groups in the adduct can occur under conditions of initiating by metal-complex systems in the presence of hydrogen donor chain transfer at C-H bond, at C-Br one, is also possible to form compounds containing one bromine atom less than adducts. 

The initiation of polymerizations by metal-containing catalysts broadens the synthetic possibilities significantly. In many cases it is the only useful method to polymerize certain kinds of monomers or to polymerize them in a stereospecific way. Examples for metal-containing catalysts are chromium oxide-containing catalysts (Phillips-Catalysts) for ethylene polymerization, metal organic coordination catalysts (Ziegler-Natta catalysts) for the polymerization of ethylene, a-olefins and dienes (see Sect. 3.3.1), palladium catalysts and the metallocene catalysts (see Sect. 3.3.2) that initiate not only the polymerization of (cyclo)olefins and dienes but also of some polar monomers. 

The initiation of polymerizations by metal-containing catalysts broadens the synthetic possibilities significantly. In many cases, it is the only useful method to polymerize certain kinds of monomers or to polymerize them in a stereospecific way. Examples for metal-containing catalysts are chromium oxide-containing catalysts (Phillips catalysts) for ethylene polymerization ... 

Chemical Initiation by Metais or Metal-Containing Compounds... 

Concentrate. An action to intensify in strength or purity by the removal of valueless or unneeded constituents, ie separation of ore or metal from its containing rock or earth. The concentration of ores always proceeds by steps or stages. Liberation of mineral values is often the initial step. Concentrate also means a product of concentration, ie, enriched ore after removal of waste in a beneficiation mill. 

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