Video Experimental Relacionado
Updated: May 8, 2026
07:28
Ethylene Polymerizations Using Parallel Pressure Reactors and a Kinetic Analysis of Chain Transfer Polymerization
Published on: November 27, 2015
Mono ((imidazolin-2-iminato) complejos de titanio para la polimerización de etileno a bajas cantidades de
Dana Shoken1, Manab Sharma, Mark Botoshansky
1Schulich Faculty of Chemistry, Institute of Catalysis Science and Technology, Technion - Israel Institute of Technology, Technion City, 32000 Haifa, Israel.
Journal of the American Chemical Society
|August 17, 2013
Resumen
Los investigadores exploraron la polimerización del etileno utilizando complejos de titanio con ligandos voluminosos de imidazolina-2-iminato. La actividad catalítica óptima se logró con complejos específicos con una relación aluminio/titanio de 8.
Área de la Ciencia:
- Química de Polímeros La Química de Polímeros es la química de los polímeros.
- Química organometálica Química orgánica de los metales.
- La catálisis de la catálisis.
Sus antecedentes:
- Los complejos de titanio son catalizadores cruciales en la polimerización de las olefinas.
- Los ligandos voluminosos pueden influir en la actividad del catalizador y en las propiedades del polímero.
- Comprender las especies activas es clave para optimizar los procesos de polimerización.
Objetivo del estudio:
- Para investigar la polimerización del etileno utilizando complejos de titanio con ligandos voluminosos de imidazolina-2-iminato.
- Para preparar y caracterizar el complejo LTiCl3 y sus derivados metilados.
- Determinar las condiciones óptimas para la actividad catalítica, centrándose en las proporciones de cocatalizador.
Principales métodos:
- Síntesis de complejos de titanio con ligandos imidazolin-2-iminato.
- Experimentos de polimerización de etileno con el uso de cocatalizadores de metilaluminoxano (MAO) y/o tris ((pentafluorofenil) boro (TTPB).
- Caracterización de los complejos de titanio y análisis de la actividad de polimerización.
Principales resultados:
- Exploración de la polimerización del etileno con complejos de titanio y cocatalizadores MAO/TTPB.
- Preparación del complejo LTiCl3 y sus formas metiladas para estudiar especies activas.
- Identificación de una relación óptima aluminio:titanio de 8 para la máxima actividad catalítica con ciertos complejos.
Conclusiones:
- El estudio proporciona información sobre las especies activas involucradas en la polimerización del etileno con sistemas de titanio-imidazolin-2-iminato.
- El rendimiento del catalizador es sensible a la estructura del ligando y la relación del cocatalizador.
- Las condiciones optimizadas, incluida una relación Al:Ti de 8, pueden conducir a una mayor actividad catalítica.
Más Videos Relacionados
Videos de Conceptos Relacionados
01:22Alkenes via Reductive Coupling of Aldehydes or Ketones: McMurry Reaction
The radical dimerization of ketones or aldehydes gives vicinal diols through a pinacol coupling reaction. However, the behavior of titanium metals used for the reaction as a source of electrons is unusual. When the reaction is carried out in the presence of titanium, diols can be isolated at low temperatures. Else titanium further reacts with diols, forming alkenes through the McMurry reaction.
00:53Olefin Metathesis Polymerization: Acyclic Diene Metathesis (ADMET)
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...
01:13Olefin Metathesis Polymerization: Overview
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...
01:17Ziegler–Natta Chain-Growth Polymerization: Overview
Ziegler–Natta polymerization is another form of addition or chain‐growth polymerization used for synthesizing linear polymers over branched polymers. The catalyst used for polymerization is the Ziegler–Natta catalyst, named after Karl Ziegler and Giulio Natta, who developed it in 1953. This catalyst is an organometallic complex of titanium tetrachloride and triethyl aluminum, with the active form of the catalyst being an alkyl titanium compound. Using the Ziegler–Natta catalyst, high molecular...
02:35Free-Radical Chain Reaction and Polymerization of Alkenes
The conversion of alkenes to macromolecules called polymers is a reaction of high commercial importance. The structure of the polymer is defined by a repeating unit, while the terminal groups are considered insignificant. The average degree of polymerization represents the number of repeating units in the polymer molecule and is denoted by the subscript n.
01:16Olefin 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...