Visualization of on-surface ethylene polymerization through ethylene insertion.
Science
; 375(6585): 1188-1191, 2022 03 11.
Article
en En
| MEDLINE
| ID: mdl-35271314
ABSTRACT
Polyethylene production through catalytic ethylene polymerization is one of the most common processes in the chemical industry. The popular Cossee-Arlman mechanism hypothesizes that the ethylene be directly inserted into the metal-carbon bond during chain growth, which has been awaiting microscopic and spatiotemporal experimental confirmation. Here, we report an in situ visualization of ethylene polymerization by scanning tunneling microscopy on a carburized iron single-crystal surface. We observed that ethylene polymerization proceeds on a specific triangular iron site at the boundary between two carbide domains. Without an activator, an intermediate, attributed to surface-anchored ethylidene (CHCH3), serves as the chain initiator (self-initiation), which subsequently grows by ethylene insertion. Our finding provides direct experimental evidence of the ethylene polymerization pathway at the molecular level.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Idioma:
En
Revista:
Science
Año:
2022
Tipo del documento:
Article
País de afiliación:
China