Anion effects in the formation of the active catalyst in the Ruhrchemie - Rhône-Poulenc aqueous biphasic hydroformylation process. Are there any?1

The water soluble [Rh(OAc)(CO)(mtppms)^sub 2^] containing monosulfonated triphenylphosphine ligands was prepared for the first time and its hydrogenation was studied in aqueous solutions. In the presence of additional mtppms, the reaction yielded [RhH(CO)(mtppms)^sub 3^], a close analogue of [RhH(CO)(mtppts)^sub 3^], the immediate catalyst precursor in the Ruhrchemie - Rhône-Poulenc aqueous biphasic hydroformylation process. The extent of the [Rh(OAc)(CO)(mtppms)^sub 2^] [arrow right] [RhH(CO)(mtppms)^sub 3^] transformation strongly depended on the solution pH, similar to the case of the hydrogenation of [RhCl(CO)(mtppms)^sub 2^] studied earlier. In this respect, RhCl^sub 3^*aq and Rh(OAc)^sub 3^*aq can be used equally well for the in situ preformation of [RhH(CO)(mtppts)^sub 3^], although the latter is the preferred choice in the industrial process. [PUBLICATION ABSTRACT]