Metallocene/borate-catalyzed copolymerization of 5-N,N-diisopropylamino-1-pentene with 1-hexene or 4-methyl-1-pentene

Metallocene/borate catalysts, generated from zirconocene dimethyl compounds, LnZrMe2, and anilinium borate, [HNMe2Ph](+)[B(C6F5)(4)](-), were used to copolymerize 5-N,N-diisopropylamino-1-pentene with l-hexene and 4-methyl-1-pentene. The selected zirconocenes, bis(pentamethylcyclopentadienyl)zirconium(IV) dimethyl (Cp*2ZrMe2) and rac-ethylenebis(4,5,6,7-tetrahydroindenyl dimethyl (rac-EB(THI)ZrMe2), provided atactic and isotactic materials, respectively. The isotactic polymers produced were amorphous or crystalline depending of the monomer. The calculated reactivity ratios for the copolymerization of 5-N,N-diisopropylamino-1-pentene with l-hexene and metallocene rac-EB(THI)ZrMe2 indicate that this system approximates an ideal azeotropic copolymerization with r(1) = 1.11 and r(2) = 0.87. Estimates for the reactivity ratios for the copolymerization of 5-N,N-diisopropylamino-1-pentene with 4-methyl-1-pentene were r(1) = 3 and r(2) = I for rac-EB(THI)ZrMe2 and r(1) = 5 and r(2) = 0.5 The polymerization of l-hexene in the presence of the saturated 1-N,N-diisopropyl- for Cp*2ZrMe2. aminopentane with rac-EB(THI)ZrMe2/borate was compared with analogous copolymerizations of 1-hexene/ 5-N,N-diisopropylamino-1-pentene. The aminopentene was more effective than the aminopentane in inhibiting the rate of total monomer conversion, implicating both intra- and intermolecular mechanisms for inhibition by the amine. Copolymers of 4-methyl-1-pentene/5-N,N-diisopropylamino produced with rac-ethylenebisindenyl zirconium(IV)dimethyl (rac-EBIZrMe2)/borate have higher decomposition temperatures with increasing amounts of aminopentene. This copolymer can be protonated with HCl to yield a methanol-soluble material.