| abstract |
Orgoanometallic compounds of high carbanion yield are prepared by metallation with alkaline earth metals such as beryllium, barium, strontium, magnesium, calcium or radium or mixture of the same of certain acidic organic compounds having a pKa value of from about 15 to 35 on the MSAD scale in the presence of protic polar solvents, e.g., barium dissolved in monomethyl amine and reacted with triphenyl methane to yield trityl barium. Such organometallic compounds formed by metal-hydrogen exchange reaction are useful in initiating anionic growth-type polymerization of monomers, e.g., alkylene oxides and vinyl compounds, to form homopolymers and copolymers. The persistence of polymer carbanions created by such catalysts makes possible the controlled preparation of a variety of polymers, including block and telechelic polymers. |