Metallocene/methylaluminoxane-catalyzed copolymerizations of oxygen-functionalized long-chain olefins with ethylene

Abstract

Copolymerizations of ethylene with 10‐undecen‐1‐ol, 10‐undecenyl methyl ether, 10‐undecenyl trimethyl silyl ether, and 1‐undecene were performed with rac‐ethylene‐bis(1‐indenyl)zirconium dichloride as a catalyst and methylaluminoxane as a cocatalyst. All three oxygen‐functional comonomers copolymerized with ethylene, although the activity of the catalyst decreased considerably compared with the homopolymerization of ethylene. The conversions of the comonomers varied from 17 to 40%, depending on the amount of comonomer in the feed. Under the same conditions, the conversion of 1‐undecene was 50–75%. The incorporation (0.7–3.6 mol %, depending on the feed) and the effect on the activity of the catalyst were on the same level for all the functional comonomers, which indicates that trimethylsilyl or methyl groups do not act as effective protecting groups for oxygen atoms. According to NMR and Fourier transform infrared analyses, the final functional group in the copolymers of the trimethylsilyl ether comonomer was hydroxyl. In contrast, the methyl ether group remained untouched in the copolymer, which suggests that the formation of aluminum alkoxides via a reaction with a cocatalyst is not a prerequisite for comonomer incorporation. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 1966–1971, 2000

Randomly Functionalized Polyethylenes: In Quest of Avoiding Catalyst Deactivation

“…Interestingly, the incorporation of C 11  OH has a significantly lower effect on the melting temperature for high molecular weight products compared to low molecular weight products. These results underline the above-mentioned strong enhancement of the effect of branches on the melting temperature for low molecular weight products compared to high molecular weight products and is in line with earlier reports. , …”

“…The broad polydispersity index and low M n for the ethylene homopolymerization is likely the result of local overheating, mass transfer limitation, and chain transfer to aluminum (vide infra) during the clearly uncontrolled reaction. The addition of 1-undecene resulted in a positive comonomer effect, − and the lower melting point ( T m = 124 °C compared to 131 °C for the HDPE of entry 1 in Table ) clearly indicates the incorporation of the comonomer into the product.…”

“…These results underline the above-mentioned strong enhancement of the effect of branches on the melting temperature for low molecular weight products compared to high molecular weight products and is in line with earlier reports. 39,40 ■ CONCLUSIONS This study demonstrates that lowering the oxidation state of the titanium catalyst from 4+ to 3+, in an attempt to reduce the catalyst's oxophilicity, has a surprisingly positive effect on the tolerance of the catalyst toward hydroxyl-functionalized αolefin comonomers, including the ones having a short spacer between the olefin and oxygen functionalities such as 2propen-1-ol and 3-buten-1-ol, which were expected to readily poison the catalyst by intramolecular coordination of the oxygen. This is an important lead for the search for new catalysts capable of copolymerizing functionalized olefins without the common loss of activity.…”

Highly active ethylene/hydroxyl comonomers copolymerization using metallocene catalysts

“…Surprisingly, for the zirconocene precursors, rEIZ and rEHZ, an increased concentration of polar comonomer in the reactor feed does not affect the catalytic activity, which remains almost constant within the comonomer feed range studied (Table I, runs 1 to 14). Other results in the literature pointed out an important decrease and moderate activities of the catalysts with the addition of the polar monomer, including both metallocene2, 6, 34 and nonmetallocene35 precursors. When using the new mNIT catalyst, it is observed that the catalytic activity (i) is lower than the obtained with the zirconocene complexes, and (ii) it sharply decreases as the comonomer concentration increases.…”

Rhodium-Catalyzed, Regiospecific Functionalization of Polyolefins in the Melt

“…16,17 A selective functionalization of commodity polyolefins would bypass the challenge of developing highly active polymerization catalysts that both tolerate and incorporate functionalized comonomers. 10,11,18 We show that the rhodium-catalyzed alkane borylation, in conjunction with simple oxidation of the alkylboronate esters to alcohols (Scheme 1), 19 effectively forms polyolefins with hydroxyl groups at the terminal positions of branches. This chemistry constitutes a rare example of preparative, selective alkane functionalization.…”