Реферат: The concept of the basic role of the transition metal-carbon bond in the catalytic polymerization of olefins was formulated in the early stages of the study of Ziegler-Natta catalysts (see Ref. 1). In this connection, attempts to use the individual organometallic transition metal compounds as catalysts for olefin polymerization have been made regularly when such compounds were synthesized[2–10]. Polymerization of ethylene in the presence of organometallic compounds containing -CH3[2, 3], -C6H5[7], -CH2C6H5[5, 6], -C3H5[4, 10], -CH2-C(CH3)3[10], and -CH2-Si(CH3)3[10] as organic ligands have been reported. In some cases such compounds were considered to be “models of the active centers.” However, considering the experimental results from this point of view led to a discrepancy with the following observations: 1. The rate of olefin polymerizatton by solutions of individual organometallic compounds is very low. According to various authors, this rate ranges from 0.1 to 10 g C2H4/mmole M/hr/atm (M is a transition metal) whereas for various Ziegler-Natta catalysts it is equal to 10 to lo3 g C2H4/mmole M/hr/atm. This difference suggests that the propagation centers formed in the solutions of organometallic compounds either have a very low activity (the propagation rate constant is very low) or their number is very small. 2. An increase in the polymerization rate was observed under conditions where decomposition of the initial organometallic compounds was possible. For example, the activity increased after addition of substances (water, alkylhalides, alcohols, organic acids) which decompose the organometallic transition metal compounds. Addition of water to solutions of n-allylic complexes of chromium and zirconium (mole ratio H2O:M = 0.5) led to an increase in activity [11, 12]. As the amount of added water was increased, a precipitate was formed which was active in polymerization whereas a filtered solution had no activity.

Библиографическая ссылка: Zakharov V.A. , Ermakov Y.I.
Supported Organometallic Catalysts for Olefin Polymerization
Catalysis Reviews. 1979. V.19. N1. P.67-103. DOI: 10.1080/03602457908065101 WOS Scopus РИНЦ CAPlusCA OpenAlex Sciact

Даты:

Опубликована в печати:	1 янв. 1979 г.
Опубликована online:	6 дек. 2006 г.

Идентификаторы БД:

Web of science:	WOS:A1979GX82800003
Scopus:	2-s2.0-0018298126
РИНЦ:	23132533
Chemical Abstracts:	1979:104377
Chemical Abstracts (print):	90:104377
OpenAlex:	W2024299663
Sciact:	16181

Цитирование в БД:

БД	Цитирований
Scopus	110
OpenAlex	137

Альметрики: