NEW RESULTS WITH PHILLIPS SYSTEMS - SURFACE-COMPOUNDS OF TRANSITION-METALS .32.

Using chromium catalysts, three experiments were performed: (a) the use of higher olefins, yielding comb-like polymers which are kept in solution during the whole reaction; (b) the use of higher temperatures, which allows the isolation of low molecular weight products; (c) IR reflectance spectroscopy of catalyst surfaces during the first moments of contact with olefin. The first experiments (a) gave information on the reactivity versus time, reaction order and the lifetime of the centres. In the second experiment, at T>120 °C, other reactions become involved, including in particular isomerization, CH2 transfer and redox reactions (the formation of alkanes and Cr(IV) π-allyl complexes). In the third experiment - using the 'slow' surface FeII analog - the reversible formation of a first reaction product can be observed which already shows the IR absorption of a CH3group.