Exciting Results from the Field of Homogeneous Two-Phase Catalysis

摘要

With the advent of two-phase catalysis, the last and in fact inherent disadvantage of homogeneous catalysis relative to its heterogeneous counterpart appears to have been swept away. This breakthrough has been achieved by arranging the process such that, at least when reaction is complete, the organometallic complex serving as a catalyst on one hand, and the reaction product (and residual starting material) on the other, are located in different phases, so a. simple phase separation is sufficient forisolating the product from the catalyst (which may then be introduced immediately into another catalyst cycle). The catalyst is situated in a mobile phase which, because it is confined within the reactor, also serves as an immobilization medium. Interestingly, quite atypically, the principle itself was implemented on a large (ca. 10~6 tonnes per annum) scale in industry in the Shell higher olefins process (SHOP), as well as the Ruhrchemie Rhone-Poulenc oxo process even prior to the onset of comprehensive scientific investigation, initiated later by a number of academic research groups.I2) An indication of the significance of the process as far as the scientific world is concerned is the fact that the "standard ligand" for aqueous two-phase catalysis,triphenylphosphane trisulfonate (TPPTS). now appears in the Aldrich Catalogue of Fine Chemicals.