Aluminum olefin polymerization

However, in olefin polymerization by two-component catalysts during polymerization not only active transition metal-polymer bonds are formed, but also inactive aluminum-polymer ones, as a result of the transfer process with the participation of a co-catalyst (11, 162-164). The aluminum-polymer bonds are quenched by tritiated alcohol according to the scheme (25), so an additional tagging of the polymer occurs. The use of iodine (165, 166) as a quenching agent also results in decomposing inactive metal-polymer bonds. 

Olefin polymerization by catalysts based on transition metal halogenides is usually designated as coordinated anionic, after Natta (194). It is believed that the active metal-carbon bond in Ziegler-Natta catalysts is polarized following the type M+ - C. The polarization of the active metal-carbon bond should influence the route of its decomposition by some compounds ( polar-type inhibitors), e.g. by alcohols. When studying polymerization by Ziegler-Natta catalysts tritiated alcohols were used in many works to determine the number of metal-polymer bonds. However, as it was noted above (see Section IV), in two-component systems the polarization of the active bond cannot be judged by the results of the treatment of the system by alcohol, as the radioactivity of the polymer thus obtained results mainly from the decomposition of the aluminum-polymer bonds. 

Kennedy, J. P. and Trivedi, P. D. Cationic Olefin Polymerization Using Alkyl Halide - Alkyl-aluminum Initiator Systems. I. Reactivity Studies. II. Molecular Weight Studies. Vol. 28, pp. 83-151. 

Other half-sandwich Cr complexes which show good activities for olefin polymerization include those with ether and thioether pendant arms (93) and (94) which show activities of 1,435gmmol-1 h-1 bar-1 and 2,010 gmmol-1 h 1 bar-1 respectively.252 The half-sandwich phosphine complex (95) affords a-olefins arising from chain transfer to aluminum,256,257 while the related boratabenzene chromium(III) complex (96) generates linear PF.258,259 Cationic species have also been investigated, and (97) polymerizes ethylene with an activity of 56 gmmol-1 h-1 bar-1.260-263... 

Frjedel-Crafts Reaction. Any organic reaction brought about by the catalytic action of anhydrous aluminum chloride or related, so-called Lewis acid type catalysts. Discovered in 1877 by C. Friedel and J.M. Crafts, who later uncovered most of the types of reaction such as substitution, isomerization, elimination, cracking, olefin polymerization, addition, etc. Commonly used to displace an aromatic hydrogen atom with an alkyl, aryl or acyl chain... 

It is now clear that, when propagation centers are formed, olefin polymerization by all solid catalysts (including the Phillips Petroleum catalyst from chromium deposited on oxides, and the Standard Oil catalyst of molybdenum oxide on aluminum oxide) essentially follows the same mechanism chain growth through monomer insertion into the transition-metal-carbon bond, with precoordination of the monomer. Interestingly,... 

Group 4 elements (e.g., Ti, Zr) are used as typical catalyst precursors for olefin polymerization and serve as potent cationic components for polymer chain growth with the aid of aluminum (e.g., MAO) or boron co-catalysts. It would be more efficient and convenient if organoaluminum cations were used to polymerize olefins. From this viewpoint, following an earlier precedent with two-coordinate cations (Equation (98)),319,320 some three-coordinate organoaluminum cations hold promise, and their ability to promote polymerization of ethylene or terminal olefins is now... 

In spite of its ill-defined nature, MAO has become one of the most important aluminum alkyls it is produced commercially on a large scale to be an activator for zirconocene-based olefin polymerization catalysts (see Chapter 22). 

Solid-state hydroxyisobutylaluminoxane co-catalysts prepared by Wu [4] were as effective in activating metallocenes in olefin polymerization as the corresponding alkyl aluminoxanes but at a lower aluminum/metal ratio. 

The purpose of this study was to investigate the mechanism of cationic olefin polymerizations by model experiments using alkyl-aluminum/alkyl halide initiator systems and to correlate the results of model experiments with corresponding polymerization reactions. 

The predominant product in each case was titanium trichloride (aka "tickle 3"), an active catalyst for olefin polymerization. The preferred cocatalyst was diethyl-aluminum chloride (DEAC). TiCl from eq 3.1 contains co-crystallized aluminum trichloride. TiCl from eq 3.3 may contain small amounts of complexed aluminum alkyl. Products from eq 3.1 and 3.2 were supplied commercially by companies such as Stauffer Chemical and Dart (both now defunct). Catalyst from eq 3.3 was manufactured on site by polyolefin producers, usually in an inert hydrocarbon such as hexane. 

Mono-Cp titanium derivatives show reactivity as catalyst precursors for olefin polymerizations, particularly for the polymerization of styrene and functionalized monomers. A review highlighting the developments in the design and applications of non-metallocene complexes, including mono-Cp derivatives, as catalyst systems for a-olefin polymerization has appeared.440 Titanium complexes bearing Cp in addition to chloro ligands and activated by aluminum... 

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