Name: romp polymerization driven by ring strain
Uploaded: 2023-04-30T11:25:32.000Z
Duration: 1 min 16 s
Channel: JoVE

Recall that ring-opening metathesis polymerization, or ROMP, utilizes the olefin metathesis reaction to synthesize polymers.
ROMP involves strained cycloalkenes as substrates, such as cyclopentene.
The release of the ring strain upon open-chain product formation acts as a driving force for the reaction.
Initially, cyclopentene reacts with Grubbs catalyst, a metal carbene, and forms a metallacyclobutane intermediate.
Subsequently, the intermediate undergoes a ring-opening reaction to give a new substituted carbene.
This new carbene further reacts with another molecule of cyclopentene via a ring-opening reaction and extends the alkyl chain.
Repetition of these steps leads to the formation of an unsaturated polymer product.
Generally, the reactivity of cycloalkenes towards ROMP increases with an increase in the ring strain or a decrease in the ring size.
ROMP reactions are useful in synthesizing fully conjugated and highly unsaturated materials by retaining the unsaturation of monomers in the polymeric product.

olefin metathesis polymerization: ring-opening metathesis polymerization (romp)

Olefin Metathesis Polymerization: Ring-Opening Metathesis Polymerization (ROMP)

Ring-opening metathesis polymerization or ROMP involves strained cycloalkenes as starting materials. The mechanism of ROMP proceeds by reacting cycloalkene with Grubbs catalyst to give metallacyclobutane intermediate which undergoes a ring-opening reaction to form new carbene. The new carbene reacts with another molecule of cycloalkene. Repetition of these steps leads to the formation of an unsaturated open-chain polymer product. All these steps are reversible, however, relieving the ring strain drives the reaction forward.
The characteristic feature of the ROMP is that the unsaturation present in the reactants is conserved in the products. The reactivity of cycloalkenes towards ROMP decreases with an increase in the ring size.
Poly(phenylene vinylene) (PPV), an important polymer having alternating phenyl and vinyl groups used for electro-optical applications, is prepared by ROMP reaction. Acetyl-substituted bicyclooctadiene undergoes ROMP in the presence of Grubbs catalyst and gives processable polymer which upon heating loses two moles of acetic acid and aromatizes to form poly(phenylene vinylene) polymer.
<img alt="Ring-opening metathesis polymerization, reaction scheme, Grubbs catalyst, norbornene derivative." src="/files/ftp_upload/12935/12935_PT_Figure_1.svg" style="text-align: center; height: 95px;" data-altupdatedat="1761830439000" data-alt="Figure1" />
Figure 1. ROMP synthesis of poly(phenylene vinylene).

Ring-opening metathesis polymerization or ROMP involves strained cycloalkenes as starting materials. The mechanism of ROMP proceeds by reacting ...

olefin-metathesis-polymerization-ring-opening-metathesis

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Organic Chemistry

Unit 1

Synthetic Polymers

KEY TERMS AND CONCEPTS

romp polymerization driven by ring strain

Ring-opening metathesis polymerization, or ROMP, is a polymer method that starts with strained cycloalkenes. A cycloalkene is a ring-shaped alkene, which means it contains a carbon-carbon double bond inside a ring. In ROMP, the ring strain helps push the reaction forward.

The reaction begins when a cycloalkene reacts with Grubbs catalyst. This forms a metallacyclobutane intermediate, which then opens to make a new carbene. That new carbene can react with another cycloalkene molecule, and the same steps repeat to build an open-chain polymer with unsaturation still present.

These steps are reversible, but the loss of ring strain drives the polymerization toward products. Cycloalkenes with smaller rings are generally more reactive in ROMP than larger rings. One important example is poly(phenylene vinylene), or PPV, which has alternating phenyl and vinyl groups and is used in electro-optical applications.

PPV can be made by ROMP from acetyl-substituted bicyclooctadiene in the presence of Grubbs catalyst. The process gives a polymer that can be handled before further change. When heated, it loses two moles of acetic acid and aromatizes to form poly(phenylene vinylene).

ROMP Polymerization Driven by Ring Strain

romp-polymerization-driven-by-ring-strain

characteristics and nomenclature of homopolymers

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Naming Homopolymers from Their Monomers

Homopolymers are polymers made from identical monomer units. They contain only one repeating unit in the polymer chain. A clear example is polypropylene, which is built from propylene monomers. The name of a homopolymer is usually formed by adding the prefix poly to the monomer name. That is why the polymer from propylene is called polypropylene. When the monomer has multiple parts or substituents, the monomer name may be placed in parentheses after poly. Examples include...

characteristics and nomenclature of copolymers

characteristics-and-nomenclature-of-copolymers

Copolymers: Types, Structures, and Naming

Copolymers are polymers made from more than one kind of monomer. When different monomer species are polymerized together, the chain can contain multiple repeating units. This process is called copolymerization. Copolymers can be named by the number of monomers involved. A polymer made from two monomers is a bipolymer. Polymers made from three monomers are called terpolymers, and those made from four monomers are quaterpolymers. A common example is poly(styrene-co-acrylonitrile), also called...

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Polymer chain size and dispersity describe how uniform the chains are in a polymer sample. The weight average molecular weight, Mw, is usually higher than or equal to the number average molecular weight, Mn. These two values are equal only when every chain has the same molecular weight. That exact match is rare in synthetic polymers. It is difficult to control polymerization at the molecular level with complete accuracy. Because of this, the ratio Mw to Mn is used to describe the molecular...

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radical chain-growth polymerization: overview

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Radical Chain-Growth Polymerization Steps

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Radical Polymer Chain Growth and Ending

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radical chain-growth polymerization: chain branching

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How Radical Polymer Chains Branch

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anionic chain-growth polymerization: overview

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Anionic Polymerization and Everyday Plastics

Anionic polymerization is a chain-growth process that uses a carbanion as an intermediate. It begins when a strong nucleophile, such as an organolithium compound or a Grignard reagent, starts the reaction. Butyl lithium is the most commonly used initiator for this process. The monomers used in anionic polymerization must have a vinyl group attached to one or two electron-withdrawing groups. Acrylonitrile, vinyl chloride, and styrene each have one electron-withdrawing group and can form anionic...

anionic chain-growth polymerization: mechanism

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Living Polymers in Anionic Polymerization

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cationic chain-growth polymerization: mechanism

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Cationic Polymerization Steps in Chain Growth

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ziegler&ndash;natta chain-growth polymerization: overview

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Ziegler-Natta Catalysts and Linear Polymers

Ziegler-Natta polymerization uses a special catalyst to make linear polymers. It is a type of addition polymerization, also called chain-growth polymerization. This method favors straight polymer chains over branched ones. The catalyst is called a Ziegler-Natta catalyst. It is named after Karl Ziegler and Giulio Natta, who developed it in 1953. The catalyst is an organometallic complex made from titanium tetrachloride and triethyl aluminum. Its active form is an alkyl titanium compound. With...

step-growth polymerization: overview

Step-Growth Polymerization in Common Polymers

Step-growth polymerization is a condensation process that builds long-chain polymers from bi- or multifunctional monomers. In this reaction, the monomers are reactive from the start. Early in the process, most monomers form short oligomers, which are small reactive chains. These oligomers then link together later to make long polymer chains. Because the chains grow step by step, the reaction must run for a long time to reach high molecular weight. Many natural and synthetic polymers come from...

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Step-growth polymerization builds polymers by linking bi- or multifunctional monomers. Bifunctional monomers form linear step-growth polymers. Multifunctional monomers can form non-linear or branched polymers. As the reaction continues, the molecular weight keeps building up step by step. High molecular weight polymers usually appear at the late stages of the polymerization. By that point, about 99% of the monomers have been consumed. The extent of the reaction can be found with the Carothers...

types of step-growth polymers: polyesters

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olefin metathesis polymerization: overview

olefin-metathesis-polymerization-overview

Olefin Metathesis Polymerization Pathways

Olefin metathesis polymerization creates polymers by rearranging double bonds in olefins with a catalyst. The metathesis reaction moves substituents between two alkene molecules, and that same chemistry can be used to build polymer chains. Ruthenium-based Grubbs catalyst is the most common catalyst for this process. Grubbs catalyst contains a carbon-metal double bond called a carbene. The reaction is reversible and starts when the catalyst reacts with an alkene in a [2+2] cycloaddition. This...

Ring-opening metathesis polymerization, or ROMP, is a polymer method that starts with strained cycloalkenes. A cycloalkene is a ring-shaped alkene, which means it contains a carbon-carbon double bond inside a ring. In ROMP, the ring strain helps push the reaction forward. The reaction begins when a cycloalkene reacts with Grubbs catalyst. This forms a metallacyclobutane intermediate, which then opens to make a new carbene. That new carbene can react with another cycloalkene molecule, and the...

olefin metathesis polymerization: acyclic diene metathesis (admet)

olefin-metathesis-polymerization-acyclic-diene-metathesis-admet

ADMET Polymerization for Linear Polymers

ADMET polymerization is a type of olefin metathesis used to build linear unsaturated polymers from terminal dienes. In this reaction, molecules such as 1,8-nonadiene react with each other and release ethylene gas. The process is reversible, so the ethylene must be removed from the reaction mixture for polymerization to continue. ADMET works through a metallacyclobutane intermediate, which forms when one double bond in a terminal diene undergoes [2+2] cycloaddition with a Grubbs catalyst. The...

key terms and concepts

Learn how ring-opening metathesis polymerization uses strained cycloalkenes, Grubbs catalyst, and ring strain relief to form unsaturated polymers and PPV.

ROMP Polymerization Driven by Ring Strain | JoVE K12

organic chemistry

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ROMP Polymerization Driven by Ring Strain

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