N-Butyllithium polymerization

The situation is similar qualitatively but differs quantitatively for isoprene and 1,3-buta-diene. The dependence of Rp on initiator varies from g- to -order depending on the specific reaction system. The reaction orders for all monomers are affected hy the relative as well as absolute concentrations of initiator and monomer. Thus the dependence of Rp on initiator for the n-butyllithium polymerization of isoprene in benzene at 30°C is -order at initiator concentrations above 10-4 M but -order at initiator concentrations below 10 4 M [Van Beylen et al., 1988]. Higher initiator concentrations yield higher degrees of aggregation and lower kinetic orders. The excess of monomer over initiator is also important. Higher kinetic orders are often observed as the monomer initiator ratio increases, apparently as a result of breakup of initiator and propagating ion-pair associations by monomer. 

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See also in sourсe #XX -- [ , ]

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