Water-soluble metal complexes and catalysts Part 6. A new, efficient water-soluble catalyst for two-phase hydroformylation of olefins

The diphosphane 2,2′-bis(diphenylphosphinomethyl)-1,1′-biphenyl (1, BISBI) was sulfonated by means of oleum containing 65% SO₃. The sulfonation product, 2 (BISBIS), was purified by extraction-reextraction techniques. The sodium salts, 3, of BISBIS (2) are accessible as a mixture of several sulfonated derivatives. In the heterogeneous (biphasic) hydroformylation of propene, this sulfonated ligand 3 yields exceptionally high n/iso ratios of the resulting butyric aldehyde (rhodium catalysis). High activity and productivity at low phosphane/rhodium ratios are additional advantages of using 3. Hydroformylation of higher olefins, e.g., 1-hexene, is also within the scope of the new catalytic Rh(I)/BISBIS system.