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The number of propagating species and some rate constants of elementary acts for the polymerization of ethylene and α-olefins using supported Ziegler catalysts

✍ Scribed by A.A. Baulin; A.G. Rodionov; S.S. Ivanchev; N.M. Domareva

Publisher
Elsevier Science
Year
1980
Tongue
English
Weight
333 KB
Volume
16
Category
Article
ISSN
0014-3057

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✦ Synopsis

Concentrations of propagating species (PS) and chain propagation constants (k,) were determined for the polymerizations of ethylene, propylene, butene-1 and hexene-1 using TiCI,dMgO-AI(C2Hs) 3 (I) and TiCI,dAI203, SiO2-AI(CzHs)3 (!1) catalytic systems. The concentrations of propagating species for all monomers and a particular catalytic system are close. They give an idea of high degree of application of transition metal (-~35-39~ of total Ti for system i and --20-23°.o for system !I). Values of kp for ethylene, propylene, butene-l, hexene-1 at 70 ° for system I are 2440 _+ 240, 4.8 + 0.5, 4.6 + 0.5 and 2.5 _+ 0.3 I/mol.sec respectively. For system il, kp values for the first three monomers are 110 + !1, !.0 + 0.t and 0.13 -_+_ 0.01 I/mol.sec. These results indicate the relation of reactivity of propagating species and chemical nature of the support to the surface of which they are fixed. Rate constants for chain transfer to monomer or triethyl aluminium and spontaneous disproportionation (at 70 °) were compared for the polymerizations of ethylene and propylene using catalytic system I.

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## Abstract The number of active centers (__C__~P~) and propagation rate constant (__k__~P~) for ethylene polymerization with homogeneous catalyst LCoCl~2~ + MAO and supported catalyst LCoCl~2~/SiO~2~ + Al(__i__‐Bu)~3~, where L is 2,6‐(2,6‐(Me)~2~C~6~H~3~N = CMe)~2~C~5~H~3~N, have been determined u