Cyclopentenes copolymerization

Fig. 7 Mechanisms of 1,2-insertion and 1,3-insertion of cyclopentene into the polyethylene main chain during ethylene and cyclopentene copolymerization over Phillips catalyst...

The maximum in the polymerization rate curves for isobutyl vinyl ether,2-phenylvinyl alkyl ethers, 1-octene, norbornene/ " vinyl acetate,butene isomers,and cyclopentene copolymerizations with MA are located somewhat outside the 1 1 feed ratios. Even though 1 1 copolymer is obtained, the maximum rate of styrene-MA copolymerization is normally not at 1 1 feed equivalency. However, Tsuchida and Tomono show that addition of naphthalene causes the rate maximum point to shift... 

Cyclopentene copolymerized with norbornene in the presence of a wide variety of transition metal catalysts yields copolymalkenamers with structures (63), having rubber-like properties [42] ... 

Most Kaminsky catalysts contain only one type of active center. They produce ethylene—a-olefin copolymers with uniform compositional distributions and quite narrow MWDs which, at their limit, can be characterized by M.Jratios of about 2.0 and MFR of about 15. These features of the catalysts determine their first appHcations in the specialty resin area, to be used in the synthesis of either uniformly branched VLDPE resins or completely amorphous PE plastomers. Kaminsky catalysts have been gradually replacing Ziegler catalysts in the manufacture of certain commodity LLDPE products. They also faciUtate the copolymerization of ethylene with cycHc dienes such as cyclopentene and norhornene (33,34). These copolymers are compositionaHy uniform and can be used as LLDPE resins with special properties. Ethylene—norhornene copolymers are resistant to chemicals and heat, have high glass transitions, and very high transparency which makes them suitable for polymer optical fibers (34). 

Palladium(II) complexes possessing bidentate ligands are known to efficiently catalyze the copolymerization of olefins with carbon monoxide to form polyketones.594-596 Sulfur dioxide is an attractive monomer for catalytic copolymerizations with olefins since S02, like CO, is known to undergo facile insertion reactions into a variety of transition metal-alkyl bonds. Indeed, Drent has patented alternating copolymerization of ethylene with S02 using various palladium(II) complexes.597 In 1998, Sen and coworkers also reported that [(dppp)PdMe(NCMe)]BF4 was an effective catalyst for the copolymerization of S02 with ethylene, propylene, and cyclopentene.598 There is a report of the insertion reactions of S02 into PdII-methyl bonds and the attempted spectroscopic detection of the copolymerization of ethylene and S02.599... 

The gas chromatographic analysis of the unreacted monomers in the experiments from Table II discloses a constant C5/C8 ratio comparing the starting comonomer composition to the final composition. This means that monomer conversion is the same for 1,5-cyclooctadiene and cyclopentene in the copolymerization so that copolymer compositions are equal to the charge ratios. This result is consistent with the product analysis by 13C NMR spectroscopy where the copolymer composition is nearly identical to the starting comonomer composition. 13C NMR is used to determine the composition of the cyclopentene/1,5-cyclooctadiene copolymers as part of a detailed study of their microstructure (52). The areas of peaks at 29-30 ppm (the pp carbon from cyclopentene units) and at 27.5 ppm (the four ap carbons from the 1,5-cyclooctadiene) are used to obtain the mole fractions of the two comonomers (53, 54, 55). 13C NMR studies and copolymer composition determinations are described by Ivin (51, 56, 57) for various systems. 

Conversions of about 80% were obtained within a few minutes at 90°C. The polymer could also be cleaved by cross-metathesis with an excess of 4-octene which gave, as the main product, 9-tridecenyl-7-undecenoate, thus confirming the structure assignment as indicated in Eq. (62). The unsaturated lactone was also copolymerized with cyclooctene, 1,5-cy-clooctadiene, and cyclopentene under the previously stated conditions to afford linear copolymers which were high molecular weight, unsaturated, rubbery polyesters (110). 

Counterion effects similar to those in ionic chain copolymerizations of alkenes (Secs. 6-4a-2, 6-4b-2) are present. Thus, copolymerizations of cyclopentene and norbomene with rhenium- and ruthenium-based initiators yield copolymers very rich in norbomene, while a more reactive (less discriminating) tungsten-based initiator yields a copolymer with comparable amounts of the two comonomers [Ivin, 1987]. Monomer reactivity ratios are also sensitive to solvent and temperature. Polymer conformational effects on reactivity have been observed in NCA copolymerizations where the particular polymer chain conformation, which is usually solvent-dependent, results in different interactions with each monomer [Imanishi, 1984]. 

A terpolymer has been prepared from cyclopentene, sulfur dioxide, and acrylonitrile by Y. Yamashita and co-workers. The mechanism was recognized as a binary copolymerization between a cyclopentene/S02 complex and free acrylonitrile. 

Spontaneous copolymerization of cyclopentene (CPT) with sulfur dioxide (SOt) suggests the participation of a charge transfer complex in the initiation and propagation step of the copolymerization. The ESR spectrum together with chain transfer and kinetic studies showed the presence of long lived SOg radical. Terpolymerization with acrylonitrile (AN) was analyzed as a binary copolymerization between CPT-SOt complex and free AN, and the dilution effect proved this mechanism. Moderately high polymers showed enhanced thermal stability, corresponding to the increase of AN content in the terpolymer. 

As a development of our studies on charge transfer complexes and polymerization, we reported on the spontaneous copolymerization of cyclopentene and sulfur dioxide (11), and kinetic evidence for the participation of the charge transfer complex in the copolymerization was presented. This paper discusses the terpolymerization of cyclopentene, sulfur dioxide, and acrylonitrile to give further evidence for the charge transfer... 

The cyclopentene derivatives 89348, 92349 and 93350 do not appear to undergo ROMP, probably because their free energy of polymerization is positive. However, the fact that 1% of 89 can completely inhibit the polymerization of 90 and 91 indicates that it is likely to add preferentially to the active site forming the head carbene complex, [W](=CMeCH2CH2CH2CH=CHR), which is then unable to add any of these three monomers. It should be capable of copolymerization with norbornene. 

For 5- or 5,6-substituted norbomenes the exo-isomer is usually rather more reactive than the ewrfo-isomer. An extreme case is provided by the exo- and mfo-isomers of 190 where the exo-isomer polymerizes first, followed much more slowly by the endo-isomer see Section Vm.C.12. In other cases the endo-isomer will not polymerize but will copolymerize to some extent with its exo-isomer, as with the isomers of 197531. Other examples of this kind, where M2 will not homopolymerize using a particular catalyst, are the copolymerization of norbomene (Mi), (i) with cyclopentene (M2), catalysed by Ru(OTs)2(OH2)6597, (ii) with 192, catalysed by WClg/Me4Sn526 and (iii) with cyclohexene (M2), catalysed by WCl6/Me4Sn358,359. 

Although homopolymerization of cyclopentene results in 1,3 enchainment of the monomer units in copolymerization, blocks of cyclic monomer units are rarely observed as a consequence of the unfavorable copolymerization parameters. The isolated cyclopentene units maybe incorporated in a cis-1,2 or cis-1,3 fashion, with their ratio dependent on the catalyst used (238-240). Thus, ethylene compensates for the steric hindrance at the a carbon atom of the growing chain after insertion of the cyclopentene. 

Alternating polymers can be produced by taking advantage of the functional group tolerance, high activity, and chemoselectivity of 3. Copolymerization of cycloalkenes such as cyclooctene or cyclopentene with diacrylates affords regular alternating polymers (Eq. 15) [32]. Based on the different reactivity of the two monomers (class 1 and class 2, respectively) the more... 

Cyclopentadiene with WCVAlBrs as catalyst gives a high yield of powdery amorphous polymer (Marshall 1969) with WCU as catalyst in toluene, a soluble polymer of low MW is formed (Sumitomo 1980). It also copolymerizes with cyclopentene (Ofstead 1979) and norbomene (Minchak 1979), but the products have not been closely characterized. 

The metathesis copolymerization of the cyclobutene derivative, 7,8-bis(trifluoro-methyl)tricyclo[4.2.2.0 ]deca-3,7,9-triene (MO (7 in Ch. 13), with norbomene or cyclopentene (M2) gives copolymers that are readily converted into acetylene copolymers by elimination of l,2-bis(trifluoro)benzene from the Mi units, but the compositional sequence distribution in these copolymers is difficult to establish (Ramakrishnan 1989b). 

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