Download or read book Kinetic Investigation of Different Supported Catalysts for the Polymerization of Propylene Under Industrially Relevant Conditions written by Joana Kettner and published by Cuvillier. This book was released on 2019-05-14 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt: Scope of the work is the kinetic investigation of two fourth generation Ziegler-Natta catalysts as well as a supported metallocene catalyst for the polymerization of propylene under industrially relevant conditions and the development of simplified phenomenological kinetic models describing the polymerizations. Therein, the influence of different reaction conditions (temperature, pressure, hydrogen concentration) and, in particular, the effect of prepolymerization on catalyst kinetics as well as on polymer characteristics are studied. The Ziegler-Natta catalysts were investigated under gas-phase conditions in a 5 l horizontal stirred tank reactor operating in semi-batch mode. Both catalysts showed a similar kinetic behavior as well as hydrogen response at the different reaction conditions. Applying a prepolymerization led to an increase in activity at higher reaction temperatures as well as an improved polymer morphology. The impact of prepolymerization is catalyst specific and depends on the catalyst activity reached at main polymerization temperature. The supported metallocene catalyst was studied under bulk conditions in liquid propylene using a special 250 ml reaction calorimeter. A focus was set on procedure development (in-situ and external prepolymerization) with the target of defined prepolymerization conditions and early access to the kinetic profile. Final kinetic measurements were carried out using the developed external prepolymerization procedure. Based on the experimental studies, simplified phenomenological kinetic models are developed for each catalyst type enabling the quantitative description of the polymerization reactions at the different reaction conditions including the effect of prepolymerization. Main hypothesis for the mathematical description of the prepolymerization effect is that particle overheating at the beginning of the polymerization is the major reason for lower activities obtained when no prepolymerization is applied. For particle

Download or read book Ziegler Natta Catalysts Polymerizations written by John Jr. Boor and published by Elsevier. This book was released on 2012-12-02 with total page 689 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ziegler-Natta Catalysts and Polymerizations reviews the general aspects of Ziegler-Natta catalysts and polymerizations of olefins, dienes, and many other types of monomers. Topics covered include the physical state of the polymer during polymerization; modification of Ziegler-Natta catalysts by third components; and termination of polymer chain growth. The oxidation state of catalysts and active centers is also discussed, along with copolymerizations and block polymerizations. This book is comprised of 23 chapters and begins with an overview of Ziegler-Natta catalysts and polymerizations, their historical origins, scientific and commercial importance, and major advances in polymer science. The next chapter focuses on definitions and stereochemistry of Ziegler-Natta catalysts, together with analytical methods used to identify and quantitatively measure their structures. Some of the polymers produced commercially with Ziegler-Natta catalysts are considered. The discussion then turns to mechanisms for initiating and propagating olefins; mechanisms for stereochemical control of conjugated and nonconjugated dienes; and the basic kinetic parameters that characterize Ziegler-Natta polymerizations. This monograph is written especially for chemistry and engineering graduate students and for industrial chemists, engineers, and managers who may become involved in a Ziegler-Natta problem.

Download or read book Kinetics of Ziegler Natta Polymerization written by Tominaga Keii and published by Kluwer Academic Publishers. This book was released on 1972 with total page 280 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Catalytic Olefin Polymerization written by T. Keii and published by Elsevier. This book was released on 1990-09-12 with total page 597 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent development of a new generation of Ziegler-Natta Catalysts using either magnesium dichloride as carrier or methylaluminoxane as cocatalyst has markedly stimulated the research activity in the field of olefin polymerization. These discoveries have not only yielded economical processes for polyolefin production but also opened the way to a new generation of novel polymers. Moreover, the nature of active species is being clarified well by the effort to simplify catalyst systems. The present volume includes 38 papers from the 31 lectures and 18 posters presented at the symposium on `Recent Developments in Olefin Polymerization Catalysts', which covered the following topics: Overview of super-active homogeneous and heterogeneous catalysts, kinetic profile of olefin polymerization including copolymerization, characterization of catalysts and polymers, methods for the determination of active center concentration, role of Lewis bases on the catalysts isospecificity, polymerization mechanisms, and synthetic pathways for functionalized polyolefins. The contents are well balanced between fundamental research and application as well as between homogeneous and heterogeneous catalyst systems.

Download or read book Isospecific Polymerization of Olefins with Heterogeneous Ziegler Natta Catalysts written by Y. V. Kissin and published by . This book was released on 1985 with total page 464 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Metalorganic Catalysts for Synthesis and Polymerization written by Walter Kaminsky and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 674 pages. Available in PDF, EPUB and Kindle. Book excerpt: 45 years after the discovery of transition metals and organometallics as cocatalysts for the polymerization of olefins and for organic synthesis, these compounds have not lost their fascination. The birthday of Karl Ziegler, the great pioneer in this metalorganic catalysis, is now 100 years ago. Polyolefins and polydienes produced by Ziegler-Natta catalysis are the most important plastics and elastomers. New impulses for the polymerization of olefins have been brought about by highly active metallocenes and other single site catalysts. Just by changing the ligands of the organometallic compounds, the structure of the polymers produced can be tailored in a wide manner. In invited lectures and posters, relevant aspects of the metalorganic catalysts for synthesis and polymerization are discussed in this book. This includes mechanism and kinetics, stereochemistry, material properties, and industrial applications.