SciELO - Scientific Electronic Library Online

vol.65Development and application of solid phase extraction method for polycyclic aromatic hydrocarbons in water samples in Johannesburg area, South AfricaSynthesis and antitumour activity of gold(I) and silver(I) complexes of hydrazine-bridged diphosphine ligands author indexsubject indexarticles search
Home Pagealphabetic serial listing  

Services on Demand



Related links

  • On index processCited by Google
  • On index processSimilars in Google


South African Journal of Chemistry

On-line version ISSN 1996-840X
Print version ISSN 0379-4350


SHOZI, Mzamo L.  and  FRIEDRICH, Holger B.. Heterogenization of some PNP ligands for the oligomerization of ethylene. S.Afr.j.chem. (Online) [online]. 2012, vol.65, pp.214-222. ISSN 1996-840X.

Bis(diphenylphosphino)amine ligands were supported on Merrifield's resin and tested in catalytic ethylene oligomerization reactions with a chromium source. The supported ligands were characterized via IR, solid-state NMR, SEM and TGA-DSC. In order to compare activity of the supported and unsupported ligands, homogeneous bis(diphenylphosphino)amine ligands were synthesized and characterized via NMR, elemental analysis, IR and GC-MS. Oligomerization reactions were carried out in a Parr pressure reactor using Cr(acac)3 as the precursor and MMAO-3A as the activator. The system with the homogeneous ligands proved active in the tetramerization of ethylene, with the selectivity of 1-octene in the C8 fraction being comparable with that mentioned in literature (>98 wt%). When comparing the homogeneous ligands with their heterogeneous counterparts, the latter showed a four-fold drop in activity compared to their homogeneous counterparts. The selectivity towards the main product, 1-octene, was less than 10 wt%. These supported ligands created a system that favoured the formation of C6 products more than any other product, with C6 cyclics (methylcyclopentane and methylenecyclopentane) being the most dominant, probably due to steric effects caused by the polymer chain.

Keywords : Oligomerization; bidentate phosphine; supported catalysts.

        · text in English     · English ( pdf )


Creative Commons License All the contents of this journal, except where otherwise noted, is licensed under a Creative Commons Attribution License