Related Experiment Video
Updated: Jun 21, 2025
08:12
Depolymerizable Olefinic Polymers Based on Fused-Ring Cyclooctene Monomers
Published on: December 16, 2022
3.3K
Ring-Opening Metathesis Polymerization of Butyl Substituted trans-Cyclooctenes.
Wesley S Farrell1,2, Kathryn L Beers1,2
1Materials Science and Engineering Division, National Institute of Standards and Technology, ǂ Gaithersburg, Maryland 20899, United States.
ACS Macro Letters
|July 11, 2024
Summary
Researchers explored ring-opening metathesis polymerization of strained cyclooctenes to create branched polyethylene. While 1-butyl-trans-cyclooctene yielded regioregular polymers, broader molar mass distributions suggest non-uniform polymerization.
Area of Science:
- Polymer Chemistry
- Organic Synthesis
- Materials Science
Background:
- Ring-opening metathesis polymerization (ROMP) is a versatile technique for polymer synthesis.
- Highly-strained cyclic olefins offer unique polymerization behaviors.
- Regioregular polymers with narrow molar mass distributions are desirable for precise material properties.
Purpose of the Study:
- To investigate the ROMP of 3- and 1-butyl-trans-cyclooctenes.
- To achieve regioregular polymers with narrow molar mass distributions.
- To explore their potential as precursors for branched polyethylene.
Main Methods:
- Synthesis of 3- and 1-butyl-trans-cyclooctene monomers.
- Ring-opening metathesis polymerization using specific catalysts.
- Characterization of polymer regioregularity and molar mass distribution via NMR spectroscopy.
Main Results:
- 3-butyl-trans-cyclooctene did not yield regioregular polymers.
- 1-butyl-trans-cyclooctene produced regioregular polymers, but with higher than anticipated dispersities.
- NMR analysis indicated non-uniform propagating alkylidene species during polymerization.
Conclusions:
- The polymerization of 1-butyl-trans-cyclooctene can yield regioregular polymers.
- Broader molar mass distributions are attributed to non-uniform polymerization kinetics.
- Further optimization is needed to narrow molar mass distributions for precise polyethylene precursor applications.
More Related Videos
Related Concept Videos
01:16Olefin Metathesis Polymerization: Ring-Opening Metathesis Polymerization (ROMP)
2.6K
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...
2.6K
01:13Olefin Metathesis Polymerization: Overview
2.1K
Recently, the development of olefin metathesis polymerization advanced the field of polymer synthesis. Simply put, the reorganization of substituents on their double bonds between two olefins in the presence of a catalyst is known as the olefin metathesis reaction. The use of metathesis reaction for polymer synthesis is called olefin metathesis polymerization.
Ruthenium-based Grubbs catalyst is the most commonly used catalyst for olefin metathesis polymerization. Grubbs catalyst consists...
Ruthenium-based Grubbs catalyst is the most commonly used catalyst for olefin metathesis polymerization. Grubbs catalyst consists...
2.1K
01:26Thermal and Photochemical Electrocyclic Reactions: Overview
2.3K
Electrocyclic reactions are reversible reactions. They involve an intramolecular cyclization or ring-opening of a conjugated polyene. Shown below are two examples of electrocyclic reactions. In the first reaction, the formation of the cyclic product is favored. In contrast, in the second reaction, ring-opening is favored due to the high ring strain associated with cyclobutene formation.
2.3K
00:53Olefin Metathesis Polymerization: Acyclic Diene Metathesis (ADMET)
1.9K
Acyclic diene metathesis polymerization or ADMET polymerization involves cross-metathesis of terminal dienes, such as 1,8-nonadiene, to give linear unsaturated polymer and ethylene. As ADMET is a reversible process, the formed ethylene gas must be removed from the reaction mixture to complete the polymerization process.
Similar to cross-metathesis, ADMET also involves the formation of metallacyclobutane intermediate by [2+2] cycloaddition of one of the double bonds of a terminal diene with...
Similar to cross-metathesis, ADMET also involves the formation of metallacyclobutane intermediate by [2+2] cycloaddition of one of the double bonds of a terminal diene with...
1.9K
01:16Cycloaddition Reactions: Overview
2.5K
Cycloadditions are one of the most valuable and effective synthesis routes to form cyclic compounds. These are concerted pericyclic reactions between two unsaturated compounds resulting in a cyclic product with two new σ bonds formed at the expense of π bonds. The [4 + 2] cycloaddition, known as the Diels–Alder reaction, is the most common. The other example is a [2 + 2] cycloaddition.
2.5K
01:17Thermal Electrocyclic Reactions: Stereochemistry
2.0K
The stereochemistry of electrocyclic reactions is strongly influenced by the orbital symmetry of the polyene HOMO. Under thermal conditions, the reaction proceeds via the ground-state HOMO.
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
2.0K