Polymerization cyclooctene

Table 8.2 Acid-promoted cyclooctene polymerization with catalysts I at room temperature".

Table 8.3 Cyclooctene polymerization catalyzed by isolated indenylidene complexes XV—XVII at room temperature".

The ruthenium indenylidene complex XV, prepared in situ from RuCl(ri -p-cymene) (=C=C=CPh2)(PCy3)][CF3S03] Ib vith different acids showed very high activity in the cyclooctene polymerization (Table 8.2) [33]. 

The isolated complex XV and its derivatives having PiPr3 (XVI) and PPh3 (XVII) instead of PCy3 were also tested in cyclooctene polymerization at room temperature. Very good yields were obtained vhth XV and XVI (Table 8.3) [34[. 

Figure 6. Comparison of cyclooctene extractable macrocyclics obtained by catalyst treatment of high molecular weight polyoctenamer with extractable macrocyclics obtained during cyclooctene polymerization...

Cyclooctene polymerization Degussa-Hiils operated since 1980 cyclooctene 12 kt/a polyoctenamer (Vestenamer ) WCle 25-100°C... 

On in situ generation of indenylidene species 33 high TOP for cyclooctene polymerization could be reached. 

Table 5. Acid promoted cyclooctene polymerization at room temperature ...

Typical Examples of Calalysl Systems for the Homogeneous Ring-Opening Polymerization of Cydopentene and Cyclooctene c-,... 

Steric factors may also be important in situations where alternative modes of reaction are available. Dall Asta (44) examined the ring-opening polymerization of 3-methyl-m-cyclooctene. By infrared analysis of the product formed, he obtained quantitative information about the occurrence of head-to-head and head-to-tail successions. More than 90% of the links in the polymethyloctenamer were of the head-to-tail type, but the sterically more hindered and, therefore, unfavored head-to-head links were also observed (about 5%). Ofstead (39) investigated the ring-opening polymerization of some 1,5-cyclooctadienes substituted at one of the two... 

ROMP reactions have been extensively carried out in water, and the first examples in liquid and scC02 [15] and ionic liquids [16] have been demonstrated. ROMP of norbomene and cyclooctene in scC02 exhibit a similar efficiency to that of chlorinated organic solvents. However, the carbon dioxide based system allows simple and highly convenient work-up of the polymer products. In [bdmim][PF6] (bdmim = 1-butyl-2,3-dimethylimidazolium cation), norbornene has been polymerized using a cationic catalyst as shown in Scheme 10.15. 

Polymerization of cis-cyclooctene with the cyclic ruthenium initiator LXVIII produces cyclopolyoctenamer LXIX as the monomer undergoes ring opening and insertion into the ruthenium-carhene bond of the initiator [Bielawski et al., 2002]. Unlike most ROMPs... 

Allenylidene-ruthenium complex Ib readily promotes the ROMP of norbornene, much faster than the precursor RuCl2(PCy3)(p-cymene) [39] (Table 8.1, entry 1). The ROMP of cyclooctene requires heating at 80 °C (5 min), however a pre-activation of the catalyst allows the polymerization to take place at room temperature. The activation consists, for example, in a preliminary heating at 80 °C or UV irradiation of the catalyst before addition of the cyclic aikene, conditions under which rearrangement into indenylidene and arene displacement take place [39] (Table 8.1, entries 2,3). The arene-free allenylidene complexes, the neutral RuCl2(=C=C=CPh2)... 

It is generally agreed that alkenyl hydroperoxides are primary products in the liquid-phase oxidation of olefins. Kamneva and Panfilova (8) believe the dimeric and trimeric dialkyl peroxides they obtained from the oxidation of cyclohexene at 35° to 40° to be secondary products resulting from cyclohexene hydroperoxide. But Van Sickle and co-workers (20) report that, The abstraction/addition ratio is nearly independent of temperature in oxidation of isobutylene and cycloheptene and of solvent changes in oxidations of cyclopentene, tetramethylethylene, and cyclooctene. They interpret these results to support a branching mechanism which gives rise to alkenyl hydroperoxide and polymeric dialkyl peroxide, both as primary oxidation products. This interpretation has been well accepted (7, 13). Brill s (4) and our results show that acyclic alkenyl hydroperoxides decompose extensively at temperatures above 100°C. to complicate the reaction kinetics and mechanistic interpretations. A simplified reaction scheme is outlined below. 

Polymerization conversions of norbomene and cyclooctene using complexes 1 and 5 were performed and results summarized in Table 1. Polymerization conversion using... 

TABLE 1. Polymerization Conversion Rates Observed for Norbornene and Cyclooctene Varying Reaction Conditions"... 

Ring-opening metathesis polymerization was conducted by Verpoort et al. (4) using cyclooctene with a ruthenium Schiff base complex, (V), and proceeded with a monomer-to-catalyst ratio of 150,000 1, respectively. 

The interaction of norbornene with iron, chromium, molybdenum, and tungsten atoms affords highly unstable and uncharacterized systems of polymeric materials (102, 134). The use of other strained olefins, such as /ran.v-cyclooctene, in metal atom syntheses has yet to be explored. 

The polymerization of cyclooctene shows a pronounced dependence of the N-heterocyclic carbene ligand, due to steric effects. 

M.A. Hillmyer, W.R. Laredo, and R.H. Grubbs, Ring-opening metathesis polymerization of functionalized cyclooctenes by a ruthenium-based metathesis catalyst, Macromolecules, 28(18) 6311-16,1995. 

The synthesis of polyoctenamer has been commercialized by Huels.150 In contrast with the transformation of cyclooctene to 1,9-decadiene [Eq. (12.31)], homogeneous catalyst compositions, such as WClg + EtAlCl2, are used to promote ring-opening metathesis polymerization of cyclooctene. A polymer of narrow molecular-weight distribution with high trans content (55-85%) called Vestenamer is produced and used as blend component in different rubbers and thermoplastics. 

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