Solid olefin polymerization

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,... 

Yu. I. Yermakov and V. A. Zakharov, The Number of Propagation Centers in Solid Catalysts for Olefin Polymerization and Some Aspects of Mechanism of Their Action, in Ref. 9, p. 91. 

Solid-Catalyzed Olefin Polymerization. A third area where extremely challenging polymerization reaction engineering problems arise is in transition-metal catalyzed polymerization of olefins such as ethylene, propylene and their copolymers. 

Since mixing and good heat transfer are of vital importance in viscous polymerization reactions, a mechanically agitated continuous stirred-tank reactor is widely used in polymerization processes. Solution polymerization, emulsion polymerization, and solid-catalyzed olefin polymerization are all carried out in a mechanically agitated slurry reactor. 

Emulsion polymerization is usually carried out isothermally in batch or continuous stirred-tank reactors. Temperature control is much easier than for bulk or solution polymerization because the small ( 0.5 fim) polymer particles, which are the locus of the reaction, are suspended in a continuous aqueous medium. This complex, multiphase reactor also shows multiple steady states under isothermal conditions. In industrial practice, such a reactor often shows sustained oscillations. Solid-catalyzed olefin polymerization in a slurry batch reactor is a classic example of a slurry reactor where the solid particles change size and characteristics with time during the reaction process. 

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 two-component catalytic systems used for olefin polymerization (Ziegler-Natta catalysts) are combinations of a compound of a IV-VIII group transition metal (catalyst) and an organometallic compound of a I-III group non-transition element (cocatalyst) An active center (AC) of polymerization in these systems is a compound (at the surface in the case of solid catalysts) which contains a transition metal-alkyl bond into which monomer insertion occurs during the propagation reaction. In the case of two-component catalysts an AC is formed by alkylation of a transition metal compound with the cocatalyst, for example ... 

In this article the problems of kinetics and the mechanism of olefin polymerization proceeding on solid Ziegler-Natta catalysts are discussed, using the novel data accumulated in polymer research ... 

Such species are also part of the evolution of homogeneous and heterogeneous catalysts, including key oxidation and olefin polymerization processes. A burgeoning area is controlled immobilization of reactive centers on solid surfaces. In recognition, this Chapter concludes with a commentary on the development of heterogeneous catalysis and the synthesis of surfaces with controlled properties. 

Use Catalyst for olefins, diens, polyesters, combustion, solid propellants polymerization vulcanizing coloring for synthetic resins deposition of metal and/or oxide as memory storage for computers intermediate for synthesis glass tinting. 

Liquid solid Ion exchange Electrode reactions (including plating) Enzyme reactions peptide synthesis Liquid phase olefin polymerization Cheese making High-fructose corn sweeteners... 

The modeling of heterogeneous polymerization systems is generally more complicated than that of the homogenous systems because mass and heat transfer effects between two or more immiscible phases must be considered. Industrially important heterogeneous polymerization reactions include emulsion polymerization, suspension polymerization, precipitation polymerization, and solid-catalyzed olefin polymerization. The general polymerization rate equation is represented simply as... 

M.P. McDaniel, M.D. Jensen, K. Jayaratne, K.S. Collins, E.A. Benham, N.D. McDaniel, P.K. Das, J.L. Martin, Q. Yang, M.G. Thom, A.P. Masino, Metallocene activation by solid acids, in J. Severn, J.C. Chadwick (Eds.), Tailor-Made Polymers Via Immobilization of Alpha-Olefin Polymerization Catalysts, Wiley-VCH, Weinheim, 2008, pp. 171-210 XVI, Chapter 7. 

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