ring-opening metathesis polymerization
{{short description|Type of chain-growth polymerisation reaction involving cyclic olefins}}
{{Other uses of|ROMP|Romp (disambiguation)}}
In polymer chemistry, ring-opening metathesis polymerization (ROMP) is a type of chain-growth polymerization involving olefin metathesis.{{Citation |last=Buchmeiser |first=Michael R. |title=Ring-Opening Metathesis Polymerization |date=2009-01-28 |work=Handbook of Ring-Opening Polymerization |pages=197–225 |editor-last=Dubois |editor-first=Philippe |url=https://onlinelibrary.wiley.com/doi/10.1002/9783527628407.ch8 |access-date=2024-12-02 |edition=1 |publisher=Wiley |language=en |doi=10.1002/9783527628407.ch8 |isbn=978-3-527-31953-4 |editor2-last=Coulembier |editor2-first=Olivier |editor3-last=Raquez |editor3-first=Jean-Marie|url-access=subscription }} The reaction is driven by relieving ring strain in cyclic olefins.{{Citation |last1=Duda |first1=Andrzej |title=Thermodynamics and Kinetics of Ring-Opening Polymerization |date=2009-01-28 |work=Handbook of Ring-Opening Polymerization |pages=1–51 |editor-last=Dubois |editor-first=Philippe |url=https://onlinelibrary.wiley.com/doi/10.1002/9783527628407.ch1 |access-date=2024-12-02 |edition=1 |publisher=Wiley |language=en |doi=10.1002/9783527628407.ch1 |isbn=978-3-527-31953-4 |last2=Kowalski |first2=Adam |editor2-last=Coulembier |editor2-first=Olivier |editor3-last=Raquez |editor3-first=Jean-Marie}} A variety of heterogeneous and homogeneous catalysts have been developed for different polymers and mechanisms.{{Cite journal |last1=Hilf |first1=Stefan |last2=Kilbinger |first2=Andreas F. M. |date=2009-09-23 |title=Functional end groups for polymers prepared using ring-opening metathesis polymerization |url=https://www.nature.com/articles/nchem.347 |journal=Nature Chemistry |language=en |volume=1 |issue=7 |pages=537–546 |doi=10.1038/nchem.347 |pmid=21378934 |bibcode=2009NatCh...1..537H |issn=1755-4330|url-access=subscription }} Heterogeneous catalysts are typical in large-scale commercial processes, while homogeneous catalysts are used in finer laboratory chemical syntheses.{{Cite book |url=https://onlinelibrary.wiley.com/doi/book/10.1002/0471238961 |title=Kirk-Othmer Encyclopedia of Chemical Technology |date=2001-01-26 |publisher=Wiley |isbn=978-0-471-48494-3 |editor-last=Kirk-Othmer |edition=1 |language=en |doi=10.1002/0471238961.metanoel.a01}} Organometallic catalysts used in ROMP usually have transition metal centres, such as tungsten, ruthenium, titanium, etc., with organic ligands.{{Cite book |last1=Cowie |first1=J. M. G. |url=https://www.worldcat.org/title/ocm82473191 |title=Polymers: chemistry and physics of modern materials |last2=Arrighi |first2=V. |date=2008 |publisher=CRC Press |isbn=978-0-8493-9813-1 |edition=3rd |location=Boca Raton |oclc=ocm82473191}}
Heterogeneous catalysis
:File:Polynbornene.png. 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.{{Cite journal |last1=Ehrhorn |first1=Henrike |last2=Tamm |first2=Matthias |date=March 2019 |title=Well-Defined Alkyne Metathesis Catalysts: Developments and Recent Applications |url=https://chemistry-europe.onlinelibrary.wiley.com/doi/10.1002/chem.201804511 |journal=Chemistry – A European Journal |language=en |volume=25 |issue=13 |pages=3190–3208 |doi=10.1002/chem.201804511 |pmid=30346054 |issn=0947-6539|url-access=subscription }} The mechanism of heterogeneous ring-opening metathesis polymerization is still under investigation.{{Cite journal |last1=Greenlee |first1=Andrew J. |last2=Weitekamp |first2=Raymond A. |last3=Foster |first3=Jeffrey C. |last4=Leguizamon |first4=Samuel C. |date=2024-04-19 |title=PhotoROMP: The Future Is Bright |journal=ACS Catalysis |language=en |volume=14 |issue=8 |pages=6217–6227 |doi=10.1021/acscatal.4c00972 |issn=2155-5435 |pmc=11036397 |pmid=38660608}}
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, Norsorex and ZEONEX, among others.{{Cite journal |last=Mol |first=J. C. |date=2004-04-13 |title=Industrial applications of olefin metathesis |url=https://linkinghub.elsevier.com/retrieve/pii/S1381116903007830 |journal=Journal of Molecular Catalysis A: Chemical |series=The 15th. International Symposium on Olefin Metathesis and Related Chemistry |volume=213 |issue=1 |pages=39–45 |doi=10.1016/j.molcata.2003.10.049 |issn=1381-1169|url-access=subscription }}
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.{{Cite journal |last=Hyatt |first=Michael G. |last2=Walsh |first2=Dylan J. |last3=Lord |first3=Richard L. |last4=Andino Martinez |first4=José G. |last5=Guironnet |first5=Damien |date=2019-11-06 |title=Mechanistic and Kinetic Studies of the Ring Opening Metathesis Polymerization of Norbornenyl Monomers by a Grubbs Third Generation Catalyst |url=https://pubs.acs.org/doi/10.1021/jacs.9b09752 |journal=Journal of the American Chemical Society |language=en |volume=141 |issue=44 |pages=17918–17925 |doi=10.1021/jacs.9b09752 |issn=0002-7863|url-access=subscription }}
=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.{{Citation |last=Pojman |first=J.A. |title=Frontal Polymerization |date=2012 |work=Polymer Science: A Comprehensive Reference |pages=957–980 |url=https://linkinghub.elsevier.com/retrieve/pii/B9780444533494001242 |access-date=2024-12-02 |publisher=Elsevier |language=en |doi=10.1016/b978-0-444-53349-4.00124-2 |isbn=978-0-08-087862-1|url-access=subscription }} One example of this system is the FROMP of dicyclopentadiene with a Grubbs' catalyst initiated by heat.{{Cite journal|last1=Moneypenny|first1=Timothy P.|last2=Liu|first2=Huiying|last3=Yang|first3=Anna|last4=Robertson|first4=Ian D.|last5=Moore|first5=Jeffrey S.|date=2017-04-13|title=Grubbs-inspired metathesis in the Moore group|journal=Journal of Polymer Science Part A: Polymer Chemistry|language=en|volume=55|issue=18|pages=2935–2948|doi=10.1002/pola.28592|issn=0887-624X|bibcode=2017JPoSA..55.2935M|doi-access=free}}
See also
Further reading
- {{Cite journal |last1=Bano |first1=Tahira |last2=Zahoor |first2=Ameer Fawad |last3=Rasool |first3=Nasir |last4=Irfan |first4=Muhammad |last5=Mansha |first5=Asim |date=June 2022 |title=Recent trends in Grubbs catalysis toward the synthesis of natural products: a review |url=https://link.springer.com/10.1007/s13738-021-02463-x |journal=Journal of the Iranian Chemical Society |language=en |volume=19 |issue=6 |pages=2131–2170 |doi=10.1007/s13738-021-02463-x |issn=1735-207X|url-access=subscription }}
- {{Cite journal |last1=Sveinbjörnsson |first1=Benjamin R. |last2=Weitekamp |first2=Raymond A. |last3=Miyake |first3=Garret M. |last4=Xia |first4=Yan |last5=Atwater |first5=Harry A. |last6=Grubbs |first6=Robert H. |date=2012-09-04 |title=Rapid self-assembly of brush block copolymers to photonic crystals |journal=Proceedings of the National Academy of Sciences |volume=109 |issue=36 |pages=14332–14336 |bibcode=2012PNAS..10914332S |doi=10.1073/pnas.1213055109 |pmc=3437898 |pmid=22912408 |doi-access=free}}