CHAIN-BRANCHING ACCOMPANYING THE SYNTHESIS OF POLYSTYRENE WITH PENDENT 2-HYDROXYETHYL GROUPS - AN INVESTIGATION OF THE REACTION OF PHENYLLITHIUM WITH OXIRANE IN THE PRESENCE OF N,N,N',N'-TETRAMETHYLETHYLENEDIAMINE

The reaction of plurilithiated polystyrenes with oxirane in the presen ce of N,N,N',N'-tetramethylethylenediamine yields not only the expecte d polymers fitted with pendent 2-hydroxyethyl groups but also coupled and branched products. The side reactions are rather important when us ing a stoichiometric amount of oxirane with regard to the lithiated si tes but can be partly suppressed in presence of an excess of oxirane. A possible reaction pathway was established on the basis of a model re action: under similar conditions the reaction of phenyllithium with ox irane leads to 2-phenylethanol and to a few percents of 3,4-diphenyl- 1 -butanol and 2-(3,4-diphenylbutoxy)ethanol. However, the presence of these two diphenyl derivatives among the reaction products may explai n the existence of coupled and branched species in the functionalized polystyrene.