Contents
1 Kinetics of Olefin Polymerization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
1.1 Influence of Catalyst and Cocatalyst Concentrations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
1.2 Main Reactions of Olefin Polymerization . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . 101
1.3 Kinetic Profile of Polymerization Reactions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
1.4 Dependence of Polymerization Rate Order on Monomer Concentration . . . . . . . . . . . 102
1.5 Concentration of Monomer Near the Active Centers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108
1.6 Hydrogen Effect . . . . . . . . . . . .. . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . .. . . . . . . . . 110
1.7 Heterogeneity of Active Centers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112
1.8 Copolymerization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
1.9 Comonomer Effect in Olefin Copolymerization Reactions . . . . . . . . . . . . . . . . . . . . . . . . . 114
2 Number of Active Centers and Propagation Rate Constants for Olefin Polymerization on
ZN Catalysts . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . 116
2.1 Kinetic Methods . . . . . . . . . . . .. . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . .. . . . . . . . . 117
2.2 Radiochemical Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
2.3 Number of Active Centers in Ethylene and Propylene Polymerization on
Traditional ZN Catalysts and Supported Titanium–Magnesium Catalysts . . . . . . . . . 121
2.4 Number of the Active Centers and Propagation Rate Constants in Polymerization
in the Presence of Hydrogen . . . . . . . . . . . . .. . . . . . . . . . . . .. . . . . . . . . . . . . .. . . . . . . . . . . . .. . . . . 122
2.5 Heterogeneity of Active Centers of ZN Catalysts, Taking into Account Data on the
Distribution of Active Centers on Propagation Rate Constants and Their
Stereospecificity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130
Kinetic investigations of olefin polymerization with Ziegler–Natta (ZN) catalysts
provide information for understanding the mechanism of these reactions. Knowledge of kinetic regularities is also necessary for development of industrial productions
of polyolefins.
The complex nature of ZN catalysts, the chemical interaction between the
components of the catalyst during polymerization, the decay in activity during
polymerization, and the heterogeneity of active centers make it difficult to study
the kinetics of olefin polymerization processes and to interpret the results.
For analysis of the kinetics and mechanism of olefin polymerization it is
important to know the number of active centers, which depends on the structure
and composition of the catalyst and on the polymerization conditions. Properties
of catalysts are also determined by the characteristics of the main reactions of
the polymerization process, including initiation of active centers, propagation
of polymer chain, transfer of the growing polymer chain with the subsequent
reactivation of active centers, and deactivation of active centers.
In this review, the conventional heterogeneous ZN catalysts and modern highly
active MgCl 2 -supported catalysts, modified by electron donor stereoregulating
compounds, are considered.
The review includes two parts, in which the main features of the kinetics
of olefin polymerization with heterogeneous ZN catalysts (Sect. 1) and data on
the number of active centers and the propagation rate constants depending on the
nature of these catalysts (Sect. 2) are considered.
100
L.A. Novokshonova and V.A. Zakharov
1 Kinetics of Olefin Polymerization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
1.1 Influence of Catalyst and Cocatalyst Concentrations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
1.2 Main Reactions of Olefin Polymerization . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . 101
1.3 Kinetic Profile of Polymerization Reactions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
1.4 Dependence of Polymerization Rate Order on Monomer Concentration . . . . . . . . . . . 102
1.5 Concentration of Monomer Near the Active Centers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108
1.6 Hydrogen Effect . . . . . . . . . . . .. . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . .. . . . . . . . . 110
1.7 Heterogeneity of Active Centers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112
1.8 Copolymerization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
1.9 Comonomer Effect in Olefin Copolymerization Reactions . . . . . . . . . . . . . . . . . . . . . . . . . 114
2 Number of Active Centers and Propagation Rate Constants for Olefin Polymerization on
ZN Catalysts . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . 116
2.1 Kinetic Methods . . . . . . . . . . . .. . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . .. . . . . . . . . 117
2.2 Radiochemical Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
2.3 Number of Active Centers in Ethylene and Propylene Polymerization on
Traditional ZN Catalysts and Supported Titanium–Magnesium Catalysts . . . . . . . . . 121
2.4 Number of the Active Centers and Propagation Rate Constants in Polymerization
in the Presence of Hydrogen . . . . . . . . . . . . .. . . . . . . . . . . . .. . . . . . . . . . . . . .. . . . . . . . . . . . .. . . . . 122
2.5 Heterogeneity of Active Centers of ZN Catalysts, Taking into Account Data on the
Distribution of Active Centers on Propagation Rate Constants and Their
Stereospecificity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130
Kinetic investigations of olefin polymerization with Ziegler–Natta (ZN) catalysts
provide information for understanding the mechanism of these reactions. Knowledge of kinetic regularities is also necessary for development of industrial productions
of polyolefins.
The complex nature of ZN catalysts, the chemical interaction between the
components of the catalyst during polymerization, the decay in activity during
polymerization, and the heterogeneity of active centers make it difficult to study
the kinetics of olefin polymerization processes and to interpret the results.
For analysis of the kinetics and mechanism of olefin polymerization it is
important to know the number of active centers, which depends on the structure
and composition of the catalyst and on the polymerization conditions. Properties
of catalysts are also determined by the characteristics of the main reactions of
the polymerization process, including initiation of active centers, propagation
of polymer chain, transfer of the growing polymer chain with the subsequent
reactivation of active centers, and deactivation of active centers.
In this review, the conventional heterogeneous ZN catalysts and modern highly
active MgCl 2 -supported catalysts, modified by electron donor stereoregulating
compounds, are considered.
The review includes two parts, in which the main features of the kinetics
of olefin polymerization with heterogeneous ZN catalysts (Sect. 1) and data on
the number of active centers and the propagation rate constants depending on the
nature of these catalysts (Sect. 2) are considered.
100
L.A. Novokshonova and V.A. Zakharov