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La polimerización de metátesis de apertura de anillo regional y estereoselectiva de ciclooctenos 3-sustituidos
Shingo Kobayashi1, Louis M Pitet, Marc A Hillmyer
1Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455-0431, United States.
Journal of the American Chemical Society
|March 31, 2011
Resumen
Los investigadores sintetizaron nuevos modelos de polietileno lineal de baja densidad (LLDPE) utilizando la polimerización de metástasis de apertura de anillo (ROMP) de cis-ciclooctenos 3-sustituidos. Este método controla con precisión la estructura del polímero, produciendo materiales de polietileno de alta calidad.
Área de la Ciencia:
- Química de Polímeros La Química de Polímeros es la química de los polímeros.
- Ciencia de los materiales Ciencia de los materiales.
- Síntesis orgánica La síntesis orgánica.
Sus antecedentes:
- El polietileno lineal de baja densidad (LLDPE) es un polímero versátil con amplias aplicaciones industriales.
- El control preciso de la microestructura del polímero es crucial para adaptar las propiedades del LLDPE.
- Las rutas sintéticas existentes pueden ofrecer un control limitado sobre la regioregularidad y la estereoregularidad.
Objetivo del estudio:
- Para sintetizar muestras de polietileno lineal de baja densidad (LLDPE) modelo con microestructuras controladas.
- Para investigar la polimerización de la metátesis de apertura de anillo (ROMP) de cis-ciclooctenos 3 sustituidos (3RCOEs).
- Para evaluar el efecto del tamaño del sustituto en la selectividad de polimerización.
Principales métodos:
- Síntesis de cis-ciclooctenos 3 sustituidos (3RCOE) con diferentes grupos R (metilo, etilo, hexilo, fenilo).
- La polimerización por metástasis de apertura de anillo (ROMP) de 3RCOE utilizando el catalizador de Grubbs.
- La hidrogenación de los poli(3RCOE) resultantes para obtener modelos de LLDPE.
Principales resultados:
- ROMP de 3RCOEs procedió con una alta regionalidad y estereoselectividad, produciendo polioctenámeros con una alta regioregularidad de cabeza a cola y trans-stereoregularidad.
- La selectividad de polimerización aumentaba con el tamaño del sustituto R.
- La hidrogenación produjo LLDPE de precisión con sustituyentes de R ubicados con precisión en cada octavo carbono de la columna vertebral.
Conclusiones:
- El ROMP de 3RCOEs ofrece un método preciso para sintetizar el modelo LLDPEs.
- El tamaño del sustituto R influye en la región y la estereoselectividad de la polimerización.
- Este enfoque permite la creación de estructuras LLDPE bien definidas para aplicaciones de materiales avanzados.
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