α‐olefin oligomers and polymers with metallocene catalysts

Abstract

Metallocenes offer new synthetic routes to olefin oligomers and polymers covering a wide range of molecular weights and melting points. This paper deals with some important features of the preparation of oligomers, wax‐like polymers as well as highmolecular‐weight polymers via metallocene catalysis. Taking the oligomerization of hexene as an example, a simple kinetic scheme is established, which is suitable to describe the course of the reaction and the resulting oligomer distribution with metallocenes as catalysts. For low and high‐molecular‐weight polymers, the metallocene route to polypropylene is compared to existent processes in terms of reaction conditions and product properties. An attempt is made to separate the effect of different chain defects like chain ends, regioirregularities and comonomers on the melting point.

Analyses of Propene and 1-Hexene Oligomers from Zirconocene/MAO Catalysts - Mechanistic Implications by NMR, SEC, and MALDI-TOF MS

“…These are derived from a bmethyl elimination as chain-termination reaction (16). [24] Vinyl double bonds are observed for the octamethylzirconocene (3), the mono-phospholyl and the bis-phopholyl zirconocene (4 and 5) and for decamethylzirconocene (7). The vinylidine/vinyl ratio (from 1 H NMR) was included in Table 1.…”

“…[1 -3] We investigated the oligomerization of propene and 1-hexene of 12 different systematically alkylsubstituted zirconocenes and phospholyl-zirconocenes (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12) in combination with MAO. [4] The use of olefin oligomers as intermediates for specialty chemicals drives the interest in the catalytic oligomerization.…”

“…[5,6] A variety of metals and methods are available for the oligomerization of a-olefins, [4] but feasible processes involving well-defined catalysts are rare. [7] Full Paper: A series of Cp9(C 5 H 5 )ZrCl 2 and Cp9 2 ZrCl 2 precatalysts (Cp9 = C 5 HMe 4 , C 4 Me 4 P, C 5 Me 5 , C 5 H 4 t Bu, C 5 H 3 -1,3-t Bu 2 , C 5 H 2 -1,2,4-t Bu 3 ) together with (C 5 H 5 ) 2 ZrCl 2 was used for the directed oligomerization of propene and 1-hexene in comparative experiments. Oligomer characterization was carried out by 1 In the beginning of metallocene catalysis the finding of low molar-mass products from propene polymerizations with zirconocene catalysts was generally regarded as unfortunate.…”

“…[7] Also, a-olefin oligomers or derivatives thereof can be used as (macro)monomeric building blocks for novel graft copolymers containing oligo-olefin side chains. [15] The functionality of a double bond at the end of each chain together with the product homogeneity are the advantages of oligomers from metallocene catalysis.…”

Oligomerisation of 1-pentene with metallocene catalysts

“…At present there is no commercial application for higher odd-numbered a-olefins, although even-numbered a-olefins are widely used as co-monomers in linear low-density polyethylene (LLDPE). Applications for the use of functionalized oligomers of a-olefins with low molar masses as adhesives, fuel additives, copolymers, lubricants and fragrances were proposed by Hungenberg et al 1) . Early reports about the polymerisation of poly(1-pentene) with heterogeneous Ziegler-Natta catalysts date back to the 1960's 2,3) .…”