EXCHANGE REACTIONS BETWEEN LITHIUM ALKYL AND ALKENYL AGGREGATES IN HYDROCARBON SOLUTION

The Li nmr spectra of a number of lithium alkyls (n-, sec-, and t-butyl) together with lithiomethyl-trimethylsilane and oligomeric polyisoprenyllithium have been measured alone and in binary mixtures in cyclopentane. All the systems showed rapid mixing of the aggregated species at room temperature if t-butyllithium was not one of the components. The systems containing t-butyllithium behaved differently. Slow mixing of t-butyllithium over a period of hours was observed with both sec-butyllithium and lithiotrimethylsilane but with polyisoprenyllithium partial exchange occurred in at most a few minutes but did not proceed further. The implications of these experiments for polymerization studies is discussed. © 1969, American Chemical Society. All rights reserved.