Olefin Metathesis Reaction in Rubber Chemistry and Industry and Beyond

Abstract

The olefin metathesis reaction has showed promising application in rubber chemistry and industry in the last decades for the production of specialty rubbers (polyene rubbers, low-molecular-weight telechelic oligomers, hydrogenated diene-based rubbers, liquid rubbers, and other functional rubbers) and characterization and recycling of rubber products (waste tires or others) via ring-opening metathesis polymerization (ROMP) or the cross-metathesis (CM) degradation technique. Here, recent advances in both molecular modeling and experimental investigations of the olefin metathesis reaction in rubber chemistry and industry are reviewed, and the challenges of future applications are also prospected.

Synthesis of ultra‐high‐molecular‐weight ethylene‐propylene copolymer via quasi‐living copolymerization with N‐heterocyclic carbene ligated vanadium complexes

“…Nevertheless, the living character of polymerization was not reported in the polymerization systems as mentioned above. N ‐heterocyclic carbenes (NHCs) have been widely used as organocatalysts and ubiquitous ligands in organometallic chemistry for organic reaction, especially in olefin metathesis reaction . We also reported vanadium complexes containing NHC ligands for ethylene/propylene copolymerization and it was interesting that the catalytic activity could be kept at high level with high Al/V molar ratio due to the stability of active species contributed by NHC ligands .…”

Catalytic Living Ring Opening Metathesis Polymerisation: The Importance of Ring Strain in Chain Transfer Agents

“…Ring opening metathesis polymerisation (ROMP), which uses the metathesis of cyclic olefins to synthesise linear polymers,h as become av ery important method for polymer synthesis in biomedical, material, academic and industrial applications. [1][2][3][4][5][6][7][8] Living ROMP,w herein irreversible chaintransfer events and termination reactions are absent, is an important polymerisation technique,d ue to its excellent control of molecular weight and the narrow molecular weight distribution of the resulting polymers. [9,10] Forp olymerisations,r uthenium carbene complexes developed by Grubbs et al (G2:( 1,3-bis(2,4,6-trimethylphenyl)-2-imidazolidinylidene) dichloro (phenylmethylene)(tricyclohexylphosphine)ruthenium and G3:dichloro[1,3-bis(2,4,6-trimethylphenyl)-2imidazolidinylidene] (benzylidene)bis(3-bromopyridine)ruthenium(II)) are frequently used mainly due to their easy handling and high functional group tolerance.H owever,i n atypical living ROMP polymerisation, the ruthenium catalyst will always be covalently bound to the end of the growing polymer chain.…”

Selectively Depolymerizable Polyurethanes from Unsaturated Polyols Cleavable by Olefin Metathesis

“…Olefin metathesis is an attractive route to depolymerization of unsaturated rubbers, critically enabled by the nuanced chain microstructure (1,4‐ and 1,2‐addition products) characteristic of polydienes. [ 45–64 ] Adjacent double bonds in side‐ and main‐chain configurations are ring‐closed by Ru carbenes (Grubbs’ catalysts) to cyclopentene and cyclohexene species with concomitant cleavage of the polymer chain. [ 48,57,64 ] The further realization that cyclopentene, functionalized cyclopentenes, and other five‐membered alkene rings can be ring‐opened through judicious selection of reaction conditions has spawned recent development of polypentenamer elastomers and related materials, including networks with continuous recyclability through sequential ring‐opening and ring‐closing metathesis.…”