Preparation method effect on the properties of Ziegler-type hydrogenation catalysts based on bis(acetylacetonato)cobalt

Resumo

The turnover frequency and turnover number of Ziegler-type systems based on Co(acac)₂ · nH₂O (n = 0, 0.5, and 2) and AlEt₃ or AlEt₂(OEt) are reported in relation to the Al: Co molar ratio and to the concentrations of the initial components. Proton donor compounds have an effect on the catalytic characteristics of the systems. ESR data are presented for the interaction of Co(acac)₂ with organometallic compounds (AlEt₃, AlEt₂(OEt), Li(n-Bu), and (C₆H₅CH₂)MgCl) in the presence of various arenes. Seven preparation methods and a formation scheme are suggested for catalytic species that are active in styrene hydrogenation and are based on Co(acac)₂ combined with AlEt₃ or AlEt₂(OEt) and.