Organometallic radical anions properties

One important class of anionic-polymerization initiators are the organometallic compounds, especially those of lithium and sodium (see Chapter 5 to review the general properties of the metalloalkyls). Grignard reagents can induce polymerization of acrylonitrile and acrylate esters, but not of hydrocarbons. Initiation by organosodium compounds often involves in situ generation of the active species from sodium metal. Sodium metal catalyzes the polymerization of dienes, and the mechanism has been shown to involve a dianion formed by dimerization of the diene radical anion. An alternative initiation system for anionic polymerization involves... 

The section about organometallic compounds of Ge, Sn and Pb was divided into neutral closed-shell molecules, which comprise the largest part of the chapter, cations and anions and finally radicals. The section about closed-shell molecules is further divided into papers which report about structures and properties of molecules with multiple and those with single bonds of Ge, Sn and Pb, and work that concentrates on the elucidation of reaction mechanisms. We included all studies which report about compounds of the heavier elements Ge to Pb even when the main focus of the work was on the lighter atoms C and Si or other elements. Thus, some work which is discussed here will also be found in the chapter which focuses on Si compounds8. 

Since polystyrene is one of the oldest commercial polymers with over 9 million tonnes/yr of sales, there have been thousands of patents issued covering all aspects of its manufacture and property enhancement. The styrene monomer readily polymerizes to polystyrene either thermally or with free-radical initiators (see Chapter 6 on free-radical polymerization and Chapter 8 on nitroxide-mediated polymerization). Commercial processes for the manufacture of polystyrene are described in Chapter 3 while process modelling and optimization of styrene polymerization is examined in Chapter 5. Styrene also can be polymerized via anionic and Ziegler-Natta chemistries using organometallic initiators. Using free radical and anionic polymerization chemistries, the... 

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