Video Experimental Relacionado
Updated: Jan 1, 2026
08:12
Depolymerizable Olefinic Polymers Based on Fused-Ring Cyclooctene Monomers
Published on: December 16, 2022
3.8K
Los éteres de enol son monómeros efectivos para la polimerización de la metátesis de apertura de anillo: síntesis de
1Department of Chemistry , Stanford University , Stanford , California 94305 , United States.
Journal of the American Chemical Society
|December 28, 2019
Resumen
Los investigadores lograron la polimerización de metátesis de apertura de anillo (ROMP) de éteres de enol cíclicos, creando nuevos poliéteres degradables. Este avance permite el reciclaje del catalizador y la despolimerización del polímero, ofreciendo soluciones materiales sostenibles.
Área de la Ciencia:
- Química de los polímeros
- Síntesis orgánica
- Ciencias de los materiales
Sus antecedentes:
- Los éteres de enol típicamente apagan los catalizadores de Grubbs, limitando su uso en la polimerización.
- Los complejos de alquileno de rutenio pueden permanecer activos para la metátesis de olefinas ricas en electrones.
Objetivo del estudio:
- Para demostrar la polimerización por metástasis de apertura de anillo (ROMP) de éteres de enol cíclicos.
- Desarrollar poliéteres degradables y despolimerizables.
- Establecer métodos para la desactivación y eliminación del catalizador.
Principales métodos:
- Se utilizó el 2,3-dihidrofurano como monómero para el ROMP con catalizadores Grubbs.
- Peso molecular controlado del polímero utilizando agentes de carga del iniciador y transferencia de la cadena.
- Se han desarrollado protocolos de oxidación de H2O2 para la eliminación de catalizadores.
Principales resultados:
- Logrado el primer ejemplo de ROMP para éteres de enol cíclicos, dando lugar a poli (dihidrofurano).
- Polímeros producidos con una perfecta regioregularidad y pesos moleculares controlables.
- Se ha demostrado la desactivación del catalizador, la eliminación y la posterior despolimerización/degradación del polímero.
Conclusiones:
- Los éteres de enol cíclicos son monómeros viables para el ROMP, produciendo nuevos polímeros degradables.
- El polidihidrofurano sintetizado es reciclable a monómero y degradable a moléculas pequeñas.
- Esta investigación abre nuevas vías para el desarrollo sostenible de polímeros utilizando monómeros de éter enol.
Videos de Conceptos Relacionados
01:13Olefin Metathesis Polymerization: Overview
2.5K
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 of a...
Ruthenium-based Grubbs catalyst is the most commonly used catalyst for olefin metathesis polymerization. Grubbs catalyst consists of a...
2.5K
01:16Olefin Metathesis Polymerization: Ring-Opening Metathesis Polymerization (ROMP)
3.1K
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...
3.1K
00:53Olefin Metathesis Polymerization: Acyclic Diene Metathesis (ADMET)
2.2K
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...
2.2K
02:26Base-Catalyzed Ring-Opening of Epoxides
9.9K
Due to their highly strained structures, epoxides can readily undergo ring-opening reactions through nucleophilic substitution, either in the presence of an acid or a base. The nucleophilic substitution reactions in the presence of acid are called acid-catalyzed ring-opening reactions, and nucleophilic substitution reactions in the presence of a base are called base-catalyzed ring-opening reactions. Epoxides undergo base-catalyzed ring-opening reactions in the presence of a strong nucleophile...
9.9K
02:29Ethers from Alcohols: Alcohol Dehydration and Williamson Ether Synthesis
12.4K
Overview
Ethers can be prepared from organic compounds by various methods. Some of them are discussed below,
Preparation of Ethers by Alcohol Dehydration
In this method, in the presence of protic acids, alcohol dehydrates to produce alkenes and ethers under different conditions. For example, in the presence of sulphuric acid, dehydration of ethanol at 413 K yields ethoxyethane, whereas it yields ethene at 443 K.
Ethers can be prepared from organic compounds by various methods. Some of them are discussed below,
Preparation of Ethers by Alcohol Dehydration
In this method, in the presence of protic acids, alcohol dehydrates to produce alkenes and ethers under different conditions. For example, in the presence of sulphuric acid, dehydration of ethanol at 413 K yields ethoxyethane, whereas it yields ethene at 443 K.
12.4K
02:24Acid-Catalyzed Ring-Opening of Epoxides
8.5K
Epoxides that are three-membered ring systems are more reactive than other cyclic and acyclic ethers. The high reactivity of epoxides originates from the strain present in the ring. This ring strain acts as a driving force for epoxides to undergo ring-opening reactions either with halogen acids or weak nucleophiles in the presence of mild acid. The acid catalyst converts the epoxide oxygen, a poor leaving group, into an oxonium ion, a better leaving group, making the reaction feasible. The...
8.5K