Active Centers of the Supported Organic and Hydride Transition Metal Catalysts for Ethylene Polymerization Научная публикация
Конференция |
Transition Metals and Organometallics as Catalysts for Olefin Polymerization : International Symposium 21-24 сент. 1987 , Hamburg |
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Сборник | Transition Metals and Organometallics as Catalysts for Olefin Polymerization : Proceedings of an International Symposium, Hamburg (FRG), September 21-24, 1987 Сборник, Springer-Verlag. Berlin, Heidelberg.1988. 442 c. ISBN 9783642832789. |
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Вых. Данные | Год: 1988, Страницы: 91-100 Страниц : 10 DOI: 10.1007/978-3-642-83276-5_9 | ||||
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Реферат:
Catalytic polymerization of olefins is one of the fields of catalysis in which the concept of similarity of action mechanisms of homogeneous and heterogeneous catalysts has long been accepted. This similarity is based on the idea that in both homogeneous and heterogeneous catalysts the active center is an organometallic compound of a transition element having a metal-alkyl bond via which the polymer chain propagation occurs. On this basis a general approach to the preparation of heterogeneous polymerization catalysts is an intentional synthesis of surface organometallic compounds which are active sites of these systems. One of the methods of synthesis of such compounds consists of the interaction of organic complexes with the LxMRy composition (M is a transition element, R is an organic ligand, and L is an inorganic ligand) with surface hydroxyl groups of silica or alumina. Using this approach, efficient supported catalysts for ethylene polymerization have been obtained (Yermakov et al. 1972; Karol et al. 1972; Ballard 1973; Yermakov et al. 1981). These catalysts contain surface organometallic compounds (I) of the type (E-0)n-MLxRm (E = Si, Al; M = Ti, Zr, Hf, Cr; L is halide; R is allyl, benzyl, tetramethylsylil etc.; n = 1−3; x = 0−2; m = 1−3) as active components. It might be expected that surface organometallic compounds (I) serve as direct active sites of these systems. However, such a simple approach is inconsistent with a series of experimental data obtained:
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The number of active sites in the systems of interest is significantly smaller than the total number of surface organometallic complexes (I) (Yermakov et al. 1981, Ballard 1975). In many situations the activity of these systems can appreciably be enhanced using additional activation by heating, hydrogen treatment or UV-irradiation (Yermakov et al. 1981). In a number of cases the high activity is revealed by the systems in which surface compounds of transition metals do not have initial organic ligands at all.
Библиографическая ссылка:
Zakharov V.A.
, Nesterov G.A.
, Vasnetsov S.A.
, Thiele K.H.
Active Centers of the Supported Organic and Hydride Transition Metal Catalysts for Ethylene Polymerization
В сборнике Transition Metals and Organometallics as Catalysts for Olefin Polymerization : Proceedings of an International Symposium, Hamburg (FRG), September 21-24, 1987. – Springer-Verlag., 1988. – C.91-100. – ISBN 9783642832789. DOI: 10.1007/978-3-642-83276-5_9
Active Centers of the Supported Organic and Hydride Transition Metal Catalysts for Ethylene Polymerization
В сборнике Transition Metals and Organometallics as Catalysts for Olefin Polymerization : Proceedings of an International Symposium, Hamburg (FRG), September 21-24, 1987. – Springer-Verlag., 1988. – C.91-100. – ISBN 9783642832789. DOI: 10.1007/978-3-642-83276-5_9
Идентификаторы БД:
Chemical Abstracts | 1989:193436 |
Chemical Abstracts (print) | 110:193436 |
OpenAlex | W122519222 |
Цитирование в БД:
БД | Цитирований |
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OpenAlex | 4 |