In polymer chemistry, ring-opening metathesis polymerization (ROMP) is a type of chain-growth polymerization involving olefin metathesis. The reaction is driven by relieving ring strain in cyclic olefins. A variety of heterogeneous and homogeneous catalysts have been developed for different polymers and mechanisms. Heterogeneous catalysts are typical in large-scale commercial processes, while homogeneous catalysts are used in finer laboratory chemical syntheses. Organometallic catalysts used in ROMP usually have transition metal centres, such as tungsten, rubidium, titanium, etc., with organic ligands.
Heterogeneous catalysis
ROMP reaction giving polynorbornene. Like most commercial alkene metathesis processes, this reaction does not employ a well-defined molecular catalyst.
Heterogeneous catalysis consists of catalysts and substrates in different physical states. The catalyst is typically in solid phase. The mechanism of heterogeneous ring-opening metathesis polymerization is still under investigation.
Ring-opening metathesis polymerization of cyclic olefins has been commercialized since the 1970s. Examples of polymers produced on an industrial level through ROMP catalysis are Vestenamer and Norsorex, among others.
Mechanism
The mechanism of homogeneous ring-opening metathesis polymerization is well-studied. It is similar to any olefin metathesis reaction. Initiation occurs by forming an open coordination site on the catalyst. Propagation happens via a metallacycle intermediate formed after a 2+2 cycloaddition. When using a G3 catalyst, 2+2 cycloaddition is the rate determining step.
Frontal ring-opening metathesis polymerization
Frontal ring-opening metathesis polymerization (FROMP) is a variation of ROMP. It is a polymerization system that only reacts on a localized zone. One example of this system is the FROMP of dicyclopentadiene with a Grubbs' catalyst initiated by heat.
See also
Further reading
- Bano, Tahira; Zahoor, Ameer Fawad; Rasool, Nasir; Irfan, Muhammad; Mansha, Asim (June 2022). "Recent trends in Grubbs catalysis toward the synthesis of natural products: a review". Journal of the Iranian Chemical Society. 19 (6): 2131–2170. doi:10.1007/s13738-021-02463-x. ISSN 1735-207X.
- Sveinbjörnsson, Benjamin R.; Weitekamp, Raymond A.; Miyake, Garret M.; Xia, Yan; Atwater, Harry A.; Grubbs, Robert H. (2012-09-04). "Rapid self-assembly of brush block copolymers to photonic crystals". Proceedings of the National Academy of Sciences. 109 (36): 14332–14336. Bibcode:2012PNAS..10914332S. doi:10.1073/pnas.1213055109. PMC 3437898. PMID 22912408.
References
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- Duda, Andrzej; Kowalski, Adam (2009-01-28), Dubois, Philippe; Coulembier, Olivier; Raquez, Jean-Marie (eds.), "Thermodynamics and Kinetics of Ring-Opening Polymerization", Handbook of Ring-Opening Polymerization (1 ed.), Wiley, pp. 1–51, doi:10.1002/9783527628407.ch1, ISBN 978-3-527-31953-4, retrieved 2024-12-02
- Hilf, Stefan; Kilbinger, Andreas F. M. (2009-09-23). "Functional end groups for polymers prepared using ring-opening metathesis polymerization". Nature Chemistry. 1 (7): 537–546. Bibcode:2009NatCh...1..537H. doi:10.1038/nchem.347. ISSN 1755-4330. PMID 21378934.
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- Cowie, J. M. G.; Arrighi, V. (2008). Polymers: chemistry and physics of modern materials (3rd ed.). Boca Raton: CRC Press. ISBN 978-0-8493-9813-1. OCLC 82473191.
- Ehrhorn, Henrike; Tamm, Matthias (March 2019). "Well-Defined Alkyne Metathesis Catalysts: Developments and Recent Applications". Chemistry – A European Journal. 25 (13): 3190–3208. doi:10.1002/chem.201804511. ISSN 0947-6539. PMID 30346054.
- Greenlee, Andrew J.; Weitekamp, Raymond A.; Foster, Jeffrey C.; Leguizamon, Samuel C. (2024-04-19). "PhotoROMP: The Future Is Bright". ACS Catalysis. 14 (8): 6217–6227. doi:10.1021/acscatal.4c00972. ISSN 2155-5435. PMC 11036397. PMID 38660608.
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- Hyatt, Michael G.; Walsh, Dylan J.; Lord, Richard L.; Andino Martinez, José G.; Guironnet, Damien (2019-11-06). "Mechanistic and Kinetic Studies of the Ring Opening Metathesis Polymerization of Norbornenyl Monomers by a Grubbs Third Generation Catalyst". Journal of the American Chemical Society. 141 (44): 17918–17925. doi:10.1021/jacs.9b09752. ISSN 0002-7863.
- Pojman, J.A. (2012), "Frontal Polymerization", Polymer Science: A Comprehensive Reference, Elsevier, pp. 957–980, doi:10.1016/b978-0-444-53349-4.00124-2, ISBN 978-0-08-087862-1, retrieved 2024-12-02
- Moneypenny, Timothy P.; Liu, Huiying; Yang, Anna; Robertson, Ian D.; Moore, Jeffrey S. (2017-04-13). "Grubbs-inspired metathesis in the Moore group". Journal of Polymer Science Part A: Polymer Chemistry. 55 (18): 2935–2948. Bibcode:2017JPoSA..55.2935M. doi:10.1002/pola.28592. ISSN 0887-624X.