Polymerization of Cyclopentene

In early studies of the molecular weight-regulating efficiency of various olefins in the metathesis polymerization of cyclopentene, the results of... 

Polymerization of Cyclopentene in the Presence of 2-Pentene by WF6/C2H5A1C12 Catalyst"... 

Polymers containing rings incorporated into the main chain (e.g., by double-bond polymerization of a cycloalkene) are also capable of exhibiting stereoisomerism. Such polymers possess two stereocenters—the two atoms at which the polymer chain enters and leaves each ring. Thus the polymerization of cyclopentene to polycyclopentene [IUPAC poly(cyclopen-tane-l,2-diyl)] is considered in the same manner as that of a 1,2-disubstituted ethylene. The... 

Alkene metathesis, a remarkable reaction catalyzed by transition metal catalysts, can be traced back to Ziegler-Natta chemistry as its origin [11], In 1964, Natta et al. reported a new type polymerization of cyclopentene using Mo- or W-based catalyst, without knowing the mechanism. This was the first example of ring-opening metathesis polymerization (ROMP eq. 1.9) [12],... 

Fig. 27. Vinyl polymerization of cyclopentene and norbornene is possible using metalo-cene/MAO catalysts (137).

Polymerization of cyclopentene with metallocene catalyst and MAO gives 1,3 rather than 1,2 linked polymers. Why ... 

Table 22. Polymerization of cyclopentene by metallocene/MAO catalysts. 45 ml toluene, 5 ml cyclopentene, [Zr] = 0.5 mmol/1, [MAO] = 100 mmol/1, 25 °C, 24 h...

Weiss and co-workers reported a series of papers on the use of alkylidyne complexes as precursors for olefin metathesis catalysts. W(CCMe3)-Cl3(dme) was found to initiate ring-opening metathesis polymerization of cyclopentene [Eq. (209)] and metathesis of -hexene as well as other 1-alkenes 203.204). The rate of metathesis is slowed down by branching... 

It is of interest to point out that polypentenamer (obtained by ring opening polymerization of cyclopentene) that possesses a structure similar to that of 1,4-polybutadiene, with an extra methylene group in each monomeric unit, also undergoes cis—trans isomerization [47]. However, vinyl group formation according to... 

Complexes X, XI and XlVa mimic the steps of the ring-opening polymerization of five-membered cyclic alkenes and account for the reversibility of the polymerization of cyclopentene. In the structure of compound XlVb the double bond shifts so that, once more a five-membered ring is formed. 

The catalyst/monomer ratio required to achieve equilibrium or high conversion can be extremely low, of the order of 10 or less. Even a 10 ratio is sufficient to cause significant polymerization of cyclopentene when the catalyst system is W(=CMe)Br(CO)4/TiCl4 (Fischer, E.O. 1976). A chain mechanism is clearly indicated. 

SYNTHESIS Ring-opening polymerization of cyclopentene. Trflns-jxrlypentenamer is produced by Ziegler-Natta polymerization employing a catalyst based on aluminum triethyl/tungsten hexachloride compound. Aluminum diethylchloride/ molybdenum pentachloride compounds may be employed to produce the as isomer. Both macrocycles and linear chains are produced during polymerization. 

Poly(pentenamer) is obtained from the polymerization of cyclopentene ... 

Example 3.33 Poly(l-Pentenylene) by Metathesis Polymerization of Cyclopentene with a Ziegler-Natta-Catalyst in Solution... 

Collins, S. Kelly, W. M. The microstructure of poly(cyclopentene) produced by polymerization of cyclopentene with homogeneous Ziegler-Natta catalysts. Macromolecules 1992, 25, 233-237. 

Kelly, W. M. Taylor, N. J. Collins, S. Polymerization of cyclopentene using metallocene catalysts Polymer tacticity and properties. Macromolecules 1994, 27, 4477-4485. 

Guenther, P Haas, F. Marwede, G Nuetzel, K. Oberkirch, W Pampus, G Schoen, N. Witte, J. Ring-opening polymerization of cyclopentene (catalysts, polymerization, and product properties). Angew. Makromol. Chem. 1970,14, 87-109. 

Many but not all cycloolefins from cyclobutene to cyclododecene have been polymerized successfully. A wide range of Ziegler catalysts were explored [536,537]. The main interest is directed to the polymerization of cyclopentene. There are two pathways for the polymerization of cycloalkenes [538-543]. One is the double-bond opening ... 

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