ABSTRACT
While the model used to describe our anchored homogeneous catalyst system is a simple one, it was sufficient for the general development of these catalysts. However, a more complete understanding of the types of interactions occurring in these catalysts is important for their full optimization. Data have been obtained which indicate that the catalytically active species in these anchored homogeneous catalysts is not present as a Rh+ species in an ion pair but, rather, is attached to the heteropoly acid through the metal atom of the complex. Results have been obtained which indicate that the nature of the observed catalyst activation on hydrogenation may be the result of the removal of the diene group on the catalyst during the preparation of the anchored species. Preliminary XPS data show that there appears to be no change in the nature of the tungsten of the PTA but there were some oxidation state changes in the Rh atom of the complex. Further work in this area is on-going at present.
