Um. Stehling et al., Metallocene/borate-catalyzed copolymerization of 5-N,N-diisopropylamino-1-pentene with 1-hexene or 4-methyl-1-pentene, MACROMOLEC, 32(1), 1999, pp. 14-20
Metallocene/borate catalysts, generated from zirconocene dimethyl compounds
, LnZrMe2, and anilinium berate, [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)zirconi
um(IV) dimethyl (Cp*2ZrMe2) and rac-ethylenebis(4,5,6,7-tetrahydroindenyl d
imethyl (rac-EB(THI)ZrMe2), provided atactic and isotactic materials, respe
ctively. The isotactic polymers produced were amorphous or crystalline depe
nding of the monomer. The calculated reactivity ratios for the copolymeriza
tion of 5-N,N-diisopropylamino-1-pentene with l-hexene and metallocene rac-
EB(THI)ZrMe2 indicate that this system approximates an ideal azeotropic cop
olymerization with r(1) = 1.11 and r(2) = 0.87. Estimates for the reactivit
y 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 s
aturated 1-N,N-diisopropyl- for Cp*2ZrMe2. aminopentane with rac-EB(THI)ZrM
e2/borate was compared with analogous copolymerizations of 1-hexene/ 5-N,N-
diisopropylamino-1-pentene. The aminopentene was more effective than the am
inopentane in inhibiting the rate of total monomer conversion, implicating
both intra- and intermolecular mechanisms for inhibition by the amine. Copo
lymers of 4-methyl-1-pentene/5-N,N-diisopropylamino produced with rac-ethyl
enebisindenyl zirconium(IV)dimethyl (rac-EBIZrMe2)/borate have higher decom
position temperatures with increasing amounts of aminopentene. This copolym
er can be protonated with HCl to yield a methanol-soluble material.