Catalyst Kaminsky-Sinn

This model would explain the inability of metallocene-alkylaluminium halide systems to promote the polymerisation of propylene and higher a-olefins [94] it is obvious that there is insufficient capability of the more weakly coordinating a-olefins to form reactive, olefin-separated ion pairs by displacement of an aluminate anion from the metal centre. At any rate, the limitation of homogeneous catalysts to the polymerisation of only ethylene was a crucial obstacle to progress in this field for many years. This impediment was fortunately overcome, however, by a series of serendipitous observations [90-95, 100,101,103] that led, around the 1980s, to the discovery by Kaminsky, Sinn et al. [90, 91,94,95,100,101] that metallocenes are activated for catalysing the polymerisation of propylene and other a-olefins (without a, a-disubstituted olefins) by methylaluminoxane [30],... 

Kaminsky, Sinn and coworkers discovered in the late 1970s that an enormous increase in activity with metallocene single-site catalysts is realized when methylaluminoxane (discussed in Chapter 6) is used as cocatalyst. 

Though metallocenes have been known since 1951 (5), it was not until the work of Kaminsky, Sinn and coworkers (6, 7) in the mid- and late-1970s that the enormous potential of metallocene single site catalysts was realized. The key discovery was the dramatic increase in activity resulting from use of methylaluminoxanes in place of diethylaluminum chloride and other conventional cocatalysts. Commercial use of metallocene single site catalysts began in the early 1990s. 

The main class of metallocene catalysts used today is Kaminsky-Sinn catalysts. They are based on titanium, zirconium, or hafnium, and use methylaluminoxane as a co-catalyst. These catalysts produce very uniform comonomer incorporation and very narrow molecular weight distributions. 

Soga, K. Nakatani, H. Syndiotactic polymerization of styrene with supported Kaminsky-Sinn catalysts. Macromolecules 1990, 23, 957-959. 

In the 1970 s Kaminsky, Sinn, and others discovered that bis(cyclo-pentadienyl)dimethyltitanium when mixed with trimethyl aluminum and water provided a catalyst system capable of polymerizing ethylene [5]. The titanium structure bears some resemblance to that of ferrocene. Ferrocene was reported in 1951 [6,7] and the following year, the correct structure reported [8]. A brief, interesting account of the early days of the research on the structure proof of ferrocene has been written [9]. Because the Kaminsky catalysts have the same sandwich structure of ferrocene, they are referred to as metallocene catalysts. Just as the ferrocene ushered in a new era of organometallic chemistry, the Kaminsky metallocene spurred a tremendous amount of research in olefin polymerization catalysts. 

First metaUocene/alumoxane catalysts (Breslow, Sinn and Kaminsky) MUestones in metallocene research... 

EinaHy, in 1976, Kaminsky and Sinn in Germany discovered a new family of catalysts for ethylene polymerization. These catalysts (ie, Kaminsky catalysts) contain two components a metallocene complex, usually a zkconocene, and an organoaluminum compound, methylaluminoxane (8,9). These catalysts and thek various later modifications enable the synthesis of ethylene copolymers with a high degree of branching uniformity. Formally classified as MDPE, LLDPE, or VLDPE, the resins thus produced have a number of properties that set them apart from common PE resins in terms of performance... 

W. Kaminsky and co-workers, iu W. Kaminsky and H. Sinn, eds.. International Symposium of Transition Metals and Organometallics as Catalysts for Olefin Polymeri tion, Sponger Press, Berlin, 1988, p. 291. 

Kaminsky W, Sinn H (eds) (1988) Transition metals and organometallics as catalysts for olefin polymerization. Springer, Berlin Heidelberg New York... 

Bohm, L. L, Franke, R., Thum, G., The microreactors as a model for the description of the ethylene polymerization with heterogeneous catalysts, in Kaminsky, W., Sinn, H. (Eds.), Transition metals and organometallics as catalysts for olefln polymerization, pp. 391-403, Springer-Verlag, Berlin (1988). 

Also in the 1980s, the discovery of homogeneous stereospecific catalysts for the polymerization of 1-alkenes has opened up new prospects for research on stereospecific polymerization and stereoregular polyolefins. Ewen and coworkers79 achieved this discovery on the basis of earlier research on metallocenes in combination with alkyl-Al-oxanes by Sinn and Kaminsky.10... 

Kaminsky and Sinn et al. 115-119) have found highly active catalysts for the polymerization of ethylene combining titanium or zirconium compounds with methylalum-oxane (13)... 

In early 1981 Sinn and Kaminsky reported that mixtures of bis-cyclopentadienyl-zirconiumdimethyl (Cp2ZrMe2, a metallocene ) and methylalumoxane (MAO a complex and ill-defined mixture of oxo-bridged alkylaluminum oligomers produced by the partial hydrolysis of trimethylaluminum) produced a highly active and long-lived olefin polymerization catalyst [18]. The unique properties of this... 

Metals and Orqanometallics as Catalysts for Olefin Polymerization. Kaminsky, W. Sinn, H. eds. Springer Verlag, New York, N.Y. (1988). 

A. F. Andresen, H.-G. Cordes, J. Herwig, W. Kaminsky, A. Merck, R. Mottweiler, J. Pein, H. Sinn, and H. J. Vollmer, Halogen-free Soluble Ziegler Catalysts for Ethylene Polymerization. Control of Molecular Weight by the Choice of the Reaction Temperature, Angew. Chem. Int. Ed. Engl. 15, 630-632 (1976). 

Tait P (1988) in Kaminsky W, Sinn H (eds) Transition Metals and Organo- metallics as Catalysts for Olefin Polymerization, Springer Press, Berlin, p 309... 

Corradini P, Busico V, Guerra, G (1987) in Kaminsky W, Sinn H Transition Metals and Organometallics as Catalysts for Olefin Polymerisation. Springer Verlag, Berlin, p 337... 

F. J. Karol, K. J. Cann, B. E. Wagner in Transition Metals and Organometallics as Catalysts for Olefin Polymerization (Eds. W. Kaminsky, H. Sinn), Springer, Berlin, 1988. 

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