Dicyclopentadiene metathesis

Cyclic Polyolefins (GPO) and Gycloolefin Copolymers (GOG). Japanese and European companies are developing amorphous cycHc polyolefins as substrate materials for optical data storage (213—217). The materials are based on dicyclopentadiene and/or tetracyclododecene (10), where R = H, alkyl, or COOCH. Products are formed by Ziegler-Natta polymerization with addition of ethylene or propylene (11) or so-called metathesis polymerization and hydrogenation (12), (101,216). These products may stiU contain about 10% of the dicycHc stmcture (216). 

Ring-Opening Metathesis Polymerization. Several new titanacyclobutanes have been shown to initiate living ring-opening metathesis polymerization (ROMP) systems. These have been used to make diblock and triblock copolymers of norbomene [498-66-8] (N) and its derivatives (eg, dicyclopentadiene [77-73-6] (D)) (Fig. 2) (41). 

Poly(dicyclopentadiene). The development of polydicyclopentadiene [25038-78-2] for reaction injection molding is an area which has generated much interest. The polyDCPD is obtained via metathesis polymerization of high purity (usually greater than 98%) DCPD. Excellent reviews (61—62) of the chemistry and properties of polyDCPD have been pubHshed. The patent Hterature of polyDCPD synthesis, catalysts, modifiers, and appHcations is dominated by Hercules (44 patents) and B. F. Goodrich (43 patents) in the U.S. Other participants are Orkem, SheU, Nippon Zeon, and Teijin. 

Nickel or Cobalt acetylacetonate Metathesis Poly(dicyclopentadiene) in cyclohexane Nippon Zeon Co., Ltd 27 (1996)... 

D. Schaubroeck, S. Brughmans, C. Vercaemst, J. Schaubroeck and F. Verpoort, Qualitative FT-Raman investigation of the ring opening metathesis polymerization of dicyclopentadiene, J. Mol. Catal. A Chem., 254, 180-185 (2006). 

Figure 1.7 Ring opening metathesis polymerization of dicyclopentadiene using transition metal catalysts...

Curable poly(dicyclopentadiene), (V), was prepared by Konze et al. (4) using ring-opening metathesis polymerization with tungsten oxychloride and diallyldimethylsilane. 

The ring-opening metathesis polymerization of dicyclopentadiene was monitored by ultrasonic spectroscopy.16 The thermoset poly(dicyclopentadiene) is formed by ringopening and cross-linking in a reaction injection molding system. A reaction cell with a plastic window was constructed for use with pulse echo ultrasonic spectroscopy. Realtime measurements of density, longitudinal velocity, acoustic modulus and attenuation were monitored. Reaction kinetics were successfully determined and monitored using this technique. 

Constable, G.S. Lesser, A.J. Coughlin, E.B., Ultrasonic spectroscopic evaluation of the ringopening metathesis polymerization of dicyclopentadiene J. Polym. Sci., Part B Poly Phys. 2003, 41, 1323-1333. 

Among cyclic polyenes, cyclic dienes, trienes and tetraenes have been ring-open polymerised via the metathesis reaction. Representative of the cyclodienes most commonly used for polymerisation are 1,5-cyclooctadiene, norbornadiene (bicyclo[2.2.1]hept-2,5-diene) and dicyclopentadiene as mono-, bi- and tricyclic diolefins respectively. Cycloocta-1,5-diene metathesis polymerisation is another approach to the preparation of 1,4-polybutadiene ... 

The metathesis polymerisation of dicyclopentadiene (endo, exo) yields a linear polymer when carried out with single-component homogeneous metathesis catalysts of the metallacyclobutane or metal alkylidene type in diluted toluene solutions [142, 143]. 

The metathesis polymerisation of dicyclopentadiene, an inexpensive monomer (commercially available cyclopentadiene dimer produced by a Diels-Alder addition reaction containing ca 95 % endo and ca 5 % exo form), leads to a polymer that may be transformed into a technically useful elastomer [144-146, 179] and thermosetting resin [180,181]. The polymerisation has characteristics that make it readily adaptable to the reaction injection moulding ( rim ) process [182], The main feature of this process comes from the fact that the polymerisation is carried out directly in the mould of the desired final product. The active metathesis catalyst is formed when two separate reactants, a precatalyst (tungsten-based) component and an activator (aluminium-based) component, are combined. Monomer streams containing one respective component are mixed directly just before entering the mould, and the polymerisation into a partly crosslinked material takes place directly in this mould (Figure 6.5) [147,168,183-186],... 

Applications of the olefin metathesis reversible chemical reaction, discovered by Phillips Petroleum in the 1960s, were also developed in the subsequent years. By this reaction, Arco produces propylene from ethylene and butene-2 Hercules prepares its plastic, Metton, from dicyclopentadiene and Shell synthesizes its C12-C14 SHOP (Shell Higher Olefin Process) alcohols used for detergents. 

When cyclic alkenes are utilized as starting materials the metathesis reaction will lead to long chain polymers and/or cyclic oligomers [103, 104, 107, 108]. If a strained cyclic alkene is employed the reaction is effectively irreversible. Industrially cyclooctene (polymer Vestenamer), 2-norbornene (polymer Norsorex), and dicyclopentadiene (polymer Telene, Metton, Pentam) are used as monomers. Upon polymerization cyclooctene and 2-norbornene yield straight chain polymers while dicyclopentadiene also allows cross-linking (Scheme 5.56). 

Figure 5.46. Ring-opening metathesis polymerization (ROMP) of dicyclopentadiene catalyzed by Grubbs catalyst.

To date, low volumes of materials have been produced commercially from norbomene and cyclo-octene. Numerous products are expected to result from the materitd produced by the ROMP of dicyclopentadiene in a RIM (reaction injection molding) process. In a RIM process, two streams of a monomer are mixed in the mold where it is polymerized to the final part. In this case, one of the monomer streams contains a tungsten complex while the second contains an alkyl aluminum activator. When the two streams of dicyclopentadiene are mixed, the metathesis catalyst is formed and the monomer is ROMP polymerized (equation 12). 

Matyjaszewski et al. demonstrated that living ring opening metathesis polymerization (ROMP) could also be combined with ATRP to produce novel block copolymers [292]. ROMP of norbornene (NB) and dicyclopentadiene (CPD) were performed using an Mo-alkylidene complex, followed by reaction with p-(bro-momethyl) benzaldehyde to generate a benzyl bromide terminated polymer capable of being used as a macroinitiator for ATRP (Scheme 41). 

Metathesis is a versatile reaction that forms the basis for several important industrial processes, such as the Phillips triolefin process, which produces propene by cross-metathesis of 2-butene with ethene, and the Shell higher olefins process (SHOP), which involves a combination process that converts ethene to detergent-range olefins. Several interesting polymeric materials are commercially produced via the ROMP of different types of unsaturated cyclic monomers, including nor-bornene, cyclooctene, and dicyclopentadiene [1]. 

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