Efficient Synthesis of Functionalized Polyolefin by Incorporation of 4-Vinylcyclohexene in Ethylene Copolymerization Using Half-Titanocene Catalysts

Abstract

Copolymerizations of ethylene with vinylcyclohexene (VCHen) by using Cp′TiCl2(X) [X = O-2,6- i Pr2C6H3, Cp′ = Cp* (1); X = NC t Bu2, Cp′ = Cp* (2) and Cp (3)] catalyst systems with MAO have been explored. The copolymerizations proceeded via vinyl addition/insertion affording high molecular weight copolymers containing cyclohexenyl side chains (with uniform compositions as well as with unimodal molecular weight distributions) accompanied with certain degree of side reaction (intramolecular cyclization after VCHen insertion). Degree of the side reaction (cyclization) was dependent upon the catalyst employed, polymerization temperature, but was not affected by the time course, the Al/Ti molar ratios. The Cp−ketimide analogue (3) showed the best catalyst performance in terms of both the catalytic activity and the selectivity (lowest degree of the subsequent intramolecular cyclization) in the copolymerization. Quantitative epoxidation of the olefinic double bonds in the resultant copolymer has been achieved by using m-chloroperbenzoic acid under mild conditions; a facile, precise synthesis of functionalized polyolefin has thus been demonstrated by adopting this approach.

Stereo-controlled synthesis of polyolefins with cycloalkane groups by using late transition metals

“…25 Compared with the corresponding homopolymers, the copolymerization of cyclic alkenes with ethylene or a-olefins produces polymers with cycloalkane groups in a relatively low density. [26][27][28][29][30][31][32][33][34] The average density of cyclic units along the polymer chain can be controlled by changing the molar ratio of monomers, and the polymer properties also vary accordingly. However, the accurate control of the distribution of cyclic units in the polymer chain has not been achieved.…”

A Greener Approach for Synthesis of Functionalized Polyolefins by Introducing Reactive Functionality into Ethylene Copolymers

“…In Scheme 7, the copolymerizations of ethylene with vinylcyclohexene (VCHen), commercially produced by dimerization of butadiene, proceeded via vinyl addition affording high molecular weight copolymers containing cyclohexenyl side chains (with uniform compositions as well as with unimodal molecular weight distributions) accompanied with certain degree of side reaction (via intra-molecular cyclization after VCHen insertion) [38]. This approach could be possible, because both Cp*TiCl 2 (O-2,6-i Pr 2 C 6 H 3 ) (1) and CpTiCl 2 (N=C t Bu 2 ) (7) exhibited efficient vinylcyclohexane (VCH) incorporation in the ethylene/VCH copolymerization [39], as well as exhibited negligible comonomer incorporation in ethylene/cyclohexene copolymerization [40].…”

Living regioselective copolymerization of ethylene with nonconjugated bicyclic dienes using (salicylaldiminato)(β‐enaminoketonato) titanium catalysts

“…Compared with ethylene/α‐olefin copolymers, cycloolefin copolymers display unique properties such as high thermal stability and high refractive indices,21–23 which have therefore been widely recognized as high‐performance materials. In particular, the copolymers from ethylene and cyclodiolefins have become more attractive recently, because the further functionalization of the remaining CC double bonds in the copolymers could be possible to afford a broad range of new functional polymers with improved properties through chemical modification 24–27. So far, many studies about the copolymerization of ethylene with cyclodiolefins like 1,3‐cyclohexadiene,28, 29 2,5‐norbornadiene,30, 31 dicyclopentadiene,31–35 1,3‐cyclopentadiene,35 5‐vinyl‐2‐norbornene (VNB),36–42 or 5‐ethylidene‐2‐norbornene (ENB)43–48 have been carried out and reported, but most of the catalysts used were limited to metallocene 49.…”