SYNOPSISMg( OEt).Jbenzoyl chloride ( BC)/TiC14 catalyst has been prepared by the chemical reaction method, and the chemical composition and X-ray structure of the catalyst were studied. The effect of various conditions on catalyst activity and isospecificity were also examined. With 13C-NMR analysis, it was found that aluminum carbinolate is formed during polymerization by reaction of triethyl aluminum cocatalyst with BC remaining in the prepared catalyst. The formed aluminum carbinolate acts as an additional donor to increase the isotactic index of polypropylene (PP) . The morphology of the prepared catalyst and PP was also observed. 0 1993 John Wiley & Sons, Inc. INTRODUCTIONMany modern Ziegler-Natta catalysts for stereospecific olefin polymerization employ the high-surface-area support matrices for active transition metal catalyst sites. The first significant results were obtained in the early 1960s by using the reactive Mg compounds such as Mg( OH) C1,l hydroxylated MgO or MgS04.' In the past 20 years, there have been many reports about the various supports for TiC14 catalysts including such magnesium compounds as Mg0,3 Mg ( OH ) 2 , MgC12, Grignard compounds, and Mga l k y l~.~ Among these supports, in the early of 1970s, it was discovered that MgC12 was a good support for stereospecific catalysts. The discovery of active magnesium chloride as an ideal support for the fixation of titanium chloride and its derivatives opened a new era in the field of Ziegler-Natta catalysis, and then the preparation and characterization of MgC12-supported high-active titanium catalysts were studied inten~ively.8~~ But MgC12-supported catalysts have high chlorine content and dealing with MgC12 is not easy due to its high hygroscopicity. From these reasons, magnesium alkoxides were reported as efficient supports in some patients."Recently, Mg ( OEt )2-supported TiC14 catalysts including an organic chloride and/or an internal donor prepared by the physical milling method were studied and it was found that Mg( OEt)2 is converted to MgC12 by reaction with TiC14 and that organic chloride is necessary to promote the conversion of Mg( OEt)2 to MgCl,." In addition, the polymerization activity and isospecificity of polypropylene with the catalyst prepared by the chemical reaction method showed almost the same results as those corresponding to the physical milling method."In this paper, the Mg( OEt)2/benzoyl chloride (BC ) /TiC14 catalyst was prepared by the chemical reaction method and the chemical compositions of the prepared catalysts were examined in detail. The polymerization behaviors of the prepared catalysts were studied for various polymerization conditions. The chemical reaction of triethyl aluminum cocatalyst and BC remaining in the prepared catalyst has also been examined in detail. In addition, the morphology of the catalyst and polymer was observed. Ind. Co. and dried by passing through two columns of preactivated molecular sieve 4A. Nitrogen of extrapure grade, 99.999%, was dried by passing through the molecular sieve ...

SUMMARTCatalysts obtained from TiCl , and ball-milled Mg(OEt), in the presence of a halide compound (dichloroethane, chlorobenzene or dichlorobenzene) and/or an internal donor (ethyl benzoate or diisobutyl phthalate) were prepared for propene polymerization. The composition of the catalysts was analyzed by IR, GC, atomic absorption spectroscopy and titration. The exchange reaction between the ethoxy group of the support and the chloride group of TiCI, was found to depend profoundly on the halide compound and/or the internal donor used. The propene polymerizations were carried out using various Mg(OEt),-supported catalysts and triethylaluminium as cocatalyst with or without external donor (triethoxyphenylsilane). The catalyst activity and stereospecificity were examined. on the Mg(OR),-supported titanium catalysts for olefin polymerization '). This paper reports on the effects of the chemical composition of Mg(OEt),supported TiCl, catalysts on the activity and specificity for the synthesis of isotactic polypropylene. The effects of Lewis bases') on the present catalysts were also examined. Experimental partMuteriuk Propene (purity >%J,5%) (from Korea Petrochemical Ind. Co.) was used without further purification. Nitrogen of an extra pure grade (99,999010) was dried by passing it through the molecular sieve 3A column, and harane was passed through the molecular sieve 4A column.CCC 0025-1 16X/90/$03.00

SUMMARY: Monocyclopentadienyl compounds, CpMCl 3 (M = Ti, Zr) supported on activated MgCl 2 were used for the polymerizations of ethylene in the presence of methylaluminoxane (MAO) or a common alkylaluminium as a cocatalyst. By supporting CpMCl 3 on MgCl 2 , the catalyst activity was increased drastically to show high activity similar to MgCl 2 -supported TiCl 4 catalysts. The activity of the CpZrCl 3 /MgCl 2 catalyst was higher than that of the CpTiCl 3 /MgCl 2 one. Both catalysts gave polymers with high molecular weight (M

The catalyst systems Mg (OC2H,),/benzoyl chloride (BC)/TiCl, and Mg(OC,H,),/ethyl benzoate (EB)/TiCl, were prepared for the polymerization of propene. In case of the Mg(OC,H,),/BC/TiCl, catalyst, BC changes into the internal donor EB during the in situ preparation of the catalyst and the unchanged BC acts as additional donor after reaction with triethylaluminium (TEA). Catalyst activity and isospecificity were also studied for the two catalysts by changing the amounts of BC or EB in the polymerization of propene cocatalyzed with TEA.

Polymerization and characterization of polymers: The procedures of polymerization and characterization of polymers were described in the previous paper I). a) Part I: cf. '). a) Systematic IUPAC name of MPT = methyl 4-methylbenzoate.