Ring‐opening polymerization of unsaturated alicyclic compounds

Calderon, Nissim; Ofstead, E. A.; Judy, W. A.

doi:10.1002/pol.1967.150050901

Cited by 130 publications

(41 citation statements)

References 9 publications

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“…1) 1) . The reverse reaction of the ROMP is called back biting and proceeds intramolecularly as a degradation process generating rings and shorter chains.…”

Section: Introductionmentioning

confidence: 98%

Quantitative description of the metathesis polymerization/depolymerization equilibrium in the 1,4-polybutadiene system, 1. Influence of feed concentration and temperature

Thorn‐Csányi

Ruhland

1999

Macromol. Chem. Phys.

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SUMMARY: As reported recently, our results about the ring distribution in the polybutadiene (resp. cyclobutene) system at the metathesis polymerization/depolymerization equilibrium differ strongly from literature data published earlier. To support our findings with thermodynamic data, the product spectrum in toluene was determined at equilibrium in dependence of the feed concentration (0.1 to 1.8 mol [2C 4 H 6 2]/L) and the temperature (4 8C to 508C). For better understanding of the ring-chain distribution we introduced the turning point. This is the feed concentration at which the differential change of the ring equilibrium concentration equals that of the chains. In contrast to the terminology used until now, as for example "cut off point" or "critical concentration", the turning point describes what exactly happens in the system and has a physical meaning not only for the integral ring concentration but also for the concentration of every individual ring. The integral turning point was determined, it is temperature dependent. A strong preference for the cyclic trimers (especially for the all-trans one) was observed, which is the only ring size to show a temperature influence as a whole. The all-trans cyclic trimer is built the most exothermically in comparison with any other cyclic geometric isomer. The ctt-isomer is built endothermically. Tetramers are disfavoured regarding the pentamers. The amount of trans double bonds in the trimers at 25 8C is 97%. The trans amount decreases with increasing ring size and approaches a trans/cis ratio of about 83/17 at 25 8C. In the whole temperature region the polymeric chains show a most probable distribution. The trans/cis ratio in the polymeric fraction as a function of the temperature follows a clear tendency in accordance with the thermodynamic prediction. The trans respectively cis double bonds are distributed randomly across the chains. For all cases mentioned, quantitative thermodynamic data are presented.

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“…1) 1) . The reverse reaction of the ROMP is called back biting and proceeds intramolecularly as a degradation process generating rings and shorter chains.…”

Section: Introductionmentioning

confidence: 98%

Quantitative description of the metathesis polymerization/depolymerization equilibrium in the 1,4-polybutadiene system, 1. Influence of feed concentration and temperature

Thorn‐Csányi

Ruhland

1999

Macromol. Chem. Phys.

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“…However, the presence of trace amounts of acyclic olefins explains why the high molecular weight fractions observed are acyclic hydrocarbons, obtained by cross metathesis, rather than cyclic, polymers [7]. Cyclic alkenes, except cyclohexene, from C 4 to C 12 , yield polyalkenes which vary from amorphous elastomers to crystalline materials.…”

Section: Cyclic Olefinsmentioning

confidence: 96%

Olefin Metathesis and Related Reactions

Mortreux¹,

Petit²

1988

Industrial Applications of Homogeneous Catalysis

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“…The dependence of the stereospecificity on the nature of the organometallic compound for WCl 6 based catalytic systems has been studied by Gunther, Haas et al [283,284]. Calderon et al [285] have found that the catalytic activity at room temperature increases in the order AlEtCl z > AlEtzCI > AlEt3 for WCl 6 based systems.…”

Section: Ring Opening Polymerization Of Cycloolefinsmentioning

confidence: 97%