Catalytic Reactions in Surfactant Systems:Product Isolation and Catalyst Recycling

The potential of surfactant based reaction media was studied with different homogeneous catalytic reactions. Micellar systems with the surfactants (p-tert-octylphenoxy) polyethoxyethanol (Triton X-100) and dodecyl sulfate sodium salt were used as reaction media for the enantioselective catalytic hydrogenation of dimethyl itaconate (DMI) with the Rh catalyst complexed with the chiral ligand (2S,4S)-1-tert-butoxycarbonyl-4-diphenylphosphino-2-(diphenylphosphinometyl)-pyrrolidine (BPPM) at 30 °C and 1.1 bar, obtaining an enantiomeric excess (ee) of up to 69%. After complete hydrogenation was achieved, micellar enhanced ultrafiltration (MEUF) was used to recycle the catalyst achieving up to 95% retention. A microemulsion system stabilized with the surfactant Triton X-100 was used as alternative reaction media for the hydrogenation of DMI with a Rh catalyst complexed with the water-soluble tris(3-sulfophenyl)phosphine trisodium salt (TPPTS) at 50 °C and 1.1 bar. With the Triton X-100 system, phase separation by temperature induced separation allowed for up to four repetitive batches of DMI hydrogenations, resulting in a TON of 1530. Suzuki coupling for the synthesis of 4′-methyl-2-biphenylcarbonitrile proceeded faster in a narrow range alkylpolyglycol ether (Novel 8 = Novel 1216CO-8 Ethoxylate) three-phase system than in an dioctyl sulfosuccinate sodium salt (AOT) two-phase system, demonstrating the retarding effect of the salinization on the reaction rate.