A novel MgCl₂‐supported Ziegler‐Natta catalyst composition: Stereospecific polymerization of propene without external donor

Highly active MgCl2-supported catalysts containing novel diether donors for propene polymerization

“…Therefore, no external donors are needed for this kind of catalysts. [7][8][9][10] Common features are found in Fig. 2: [mmmm] A [mmmr] and [rrrr] A [rrrm] implying that, instead of isotactic and atactic sequences, some isotactic and syndiotactic sequences are present in the main structure of the polypropene.…”

“…[4,5] However, a novel and simplified generation of MgCl 2 -supported catalysts was developed with the discovery of 1,3-diethers. [6,7] These donors (used as internal donors) are known for having the property to produce highly active and stereospecific catalysts without any external donors. This has been ascribed to the fact that diethers show chemical stability toward TiCl 4 and AlR 3 and, therefore, are not extracted from the support.…”

Propylene polymerization over MgCl2‐supported TiCl4 catalysts bearing different amounts of a diether internal electron donor: Extrapolation to the role of internal electron donor on active site

“…In general, the specific pair of internal and external donors, such as phthalate/alkoxysilane,5 is necessary to obtain i ‐PP with high isotacticity. However, the discovery of 1,3‐diethers has made it possible to obtain highly isospecific catalysts by using only an internal donor 6…”

“…In this study, the typical 1,3‐diether 9,9‐bis(methoxymethyl)fluorine (BMMF) is selected as internal donor due to its advantages. During propylene polymerization, 1,3‐diethers in diether‐based catalysts cannot be extracted by alkylaluminum and no external donor is added, so the active sites formed in diether‐based catalyst are the ones catalyzing propylene polymerization and hence they can be characterized through the polymers obtained 6, 9, 10. Moreover, there are fewer interactions between 1,3‐diether and MgCl 2 , which make it simple to study the influence of 1,3‐diether on active sites 30.…”

Magnesium chloride supported Ziegler‐Natta catalysts containing succinate internal electron donors for the polymerization of propylene

“…Study of the effects of internal2–5 and external6–8 donors have been carried out in academic and industrial laboratories 9–15. Good internal donors can produce highly active and stereospecific catalysts without any external donor 14, 16. The widely used internal electron donors are phthalate ester and diether, such as diisobutyl phthalate (DIBP)17, 18 and 9,9‐bis(methoxymethyl)fluorene (BMMF) 19…”