Alternating Copolymerization of Ethylene and Butadiene with a Neodymocene Catalyst

Abstract

A new route to poly(ethylene‐alt‐butadiene) uses a homogeneous neodymocene/dialkylmagnesium catalyst which exhibits high activity and allows the polymerization to be easily controlled, both in terms of molecular weight and microstructure of the product. The s‐trans‐η4‐butadiene complex shown in the picture is thought to be an essential intermediate of this reaction.

Lanthanidocene Borohydrides: Alternative Precursors for Olefin and Conjugated Diene Polymerization Catalysts

“…While butadiene is generally a poison for olefin polymerization catalysts, the catalytic system 2a/Mg(Bu)(Oct) exhibits a unique increase of activity in the presence of this comonomer. [8] A similar behavior was observed with the new precursor 2b (Figure 1). The maximum activity of 574 kg Á mol À1 Á h À1 was obtained with a feed containing 30 mol-% of butadiene (run 20).…”

“…Moreover an alternating copolymer {poly[ethylene-alt-(trans-1,4-butadiene)]} has been obtained, for the first time, with high activity and at a convenient temperature (80 8C). [8] However, the determination of the structure of complex 2a is a problem, since no signal was observed by NMR spectroscopy due to the paramagnetism of neodymium. Surprisingly, complex 2b exhibited a 1 H NMR spectrum.…”

“…The results are compared to the one obtained using complex 2a (see ref. [8] and runs 25-26). Polymerizations were performed at low conversion in order to minimize the polymer composition drift.…”

“…[7,8] Nd(BH 4 ) 3 (THF) 3 was prepared following the procedure described by Cendrowski-Guillaume et al [9] [Me 2 Si(3-Me 3 Si-C 5 H 3 ) 2 NdBH 4 (THF) 2 ] (1b) Butyllithium (1.6 M solution, 12.4 mL, 19.9 mmol) was added to a 100 mLTHF solution containing 3.29 g of SiMe 2 (3-Me 3 Si-C 5 H 4 ) 2 (9.9 mmol). The mixture was stirred for 30 min at 5 8C and 6 h at room temperature.…”

Ethylene/1,3-butadiene cyclocopolymerization catalyzed by zirconocene systems

“…Cross-linked materials are, instead, obtained by using a,x-nonconjugated dienes with double bonds, that are connected by more than four carbon atoms [10,11]. In the last decade, several articles focused on COCs obtained by copolymerization of a-olefins and conjugated dienes in the presence of group IV metal [12][13][14][15][16][17][18][19][20][21] or rare earth [22][23][24] based catalysts, were reported. In particular, Longo et al recorded an unprecedented cyclopropanation reaction by copolymerization of 1,3-butadiene with a-olefins (ethylene and propylene) [12][13][14][15], catalyzed by the highly sterically hindered metallocene rac-[CH 2 (3-tertbutyl-1-indenyl) 2 ]ZrCl 2 [25], activated by methylalumoxane (MAO).…”