Abstract
The WCl6 / AliBu3 initiated polymerisation of cyclopentene has been investigated as a chain reaction and attempts have been made tostudy the reactions of the chain, ie initiation, propagation and
termination.
The reactions between alkenes and tungsten hexachloride at low
molar ratios of alkene : W have been studied using spectrophotometric
techniques and analysis of the products by gas chromatography. These studies showed that a series of reactions takes place between tungsten hexachloride and alkenes and that a number of species are present in the system which, on addition of aluminium alkyl, produce metathesis-active complexes.
Dilatometric and calorimetric techniques have been used to study the kinetics of the reaction. Previous studies conceming the kinetics
of the initiation of polymerisation were confirmed using the
dilatometric technique. Comparison of the results obtained by these
two techniques suggested that more than one active species was formed
on the addition of aluminium triisobutyl to a solution originally
containing tungsten hexachloride and cyclopentene. It is suggested
that these active species produce high and low molecular weight
materials independently and that the rate of production of polymer
is measured dilatometrically and the overall rate of consumption of
monomer calorimetrically.
Polymerisations initiated by WCl6 / 2AliBuz did not reach an
equilibrium conversion of monomer. Addition of a second aliquot
of initiator components or oxygen re-initiated polymerisation.
The termination was interpreted from kinetic data and shown to be
complex. Computer simulation of the reaction indicated second order
termination involving both propagating and terminated species.
Studies on the role of oxygen as a catalyst activator indicated the
production of a system similar in nature to WCl6 / EtOH.
| Date of Award | Nov 1980 |
|---|---|
| Original language | English |
| Awarding Institution |
|
Keywords
- metathesis polymerisation