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Titolo:
EXTERNAL SILANE DONORS IN ZIEGLER-NATTA CATALYSIS - A 3-SITE MODEL ANALYSIS OF EFFECTS ON CATALYST ACTIVE-SITES
Autore:
HARKONEN M; SEPPALA JV; SALMINEN H;
Indirizzi:
HELSINKI UNIV TECHNOL,DEPT CHEM ENGN SF-02150 ESPOO FINLAND BOREALIS POLYMERS OY SF-06101 PORVOO FINLAND
Titolo Testata:
Polymer Journal
fascicolo: 3, volume: 27, anno: 1995,
pagine: 256 - 261
SICI:
0032-3896(1995)27:3<256:ESDIZC>2.0.ZU;2-C
Fonte:
ISI
Lingua:
ENG
Soggetto:
ALKOXYSILANE DONORS; POLYMERIZATION; PROPENE;
Keywords:
ZIEGLER-NATTA CATALYSTS; EXTERNAL DONOR; ALKOXYSILANE; POLYPROPYLENE; 3-SITE MODEL;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
15
Recensione:
Indirizzi per estratti:
Citazione:
M. Harkonen et al., "EXTERNAL SILANE DONORS IN ZIEGLER-NATTA CATALYSIS - A 3-SITE MODEL ANALYSIS OF EFFECTS ON CATALYST ACTIVE-SITES", Polymer Journal, 27(3), 1995, pp. 256-261

Abstract

A three-site model of the active sites in a MgCl2-supported Ziegler-Natta catalyst was used to simulate the effects of various external alkoxysilane donors on the catalyst active sites. The simulations correlated well with the experimental data, and it is evident that the polypropylene produced by this catalyst system originates mainly from three types of active sites. One site is a highly isospecific enantiomorphicsite producing boiling heptane insoluble polymer. Two sites are responsible for the major part of the polymers of the heptane soluble firaction: a moderately isospecific enantiomorphic site (the fluctuating site) and a symmetric Bernoullian syndiospecific site. All the alkoxysilanes tested,including monoalkoxysilanes, exhibited a stabilizing role,making fluctuating sites more isospecific. In addition, the silanes having more than one alkoxy group were capable of deactivating active Ti-sites, and the selectivity of deactivation depends mainly on the size of the hydrocarbon part.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 06/07/20 alle ore 05:52:39