The kinetics of the catalytic hydrogenation of dimethyl itaconate (DMI) was studied in a biphasic cyclohexane-water system and in a [Triton X-100/1-pentanol]/cyclohexane/water microemulsion, in both cases using the water-soluble catalyst complex Rh-TPPTS. The reaction was carried out at a pressure of 1.1 bar and in the temperature range 298-308 K. A typical profile of a zero-order reaction was observed in the case of the biphasic system. Against that the reaction order for DMI changed to 1 in a microemulsion. A rate law based on an Osborn-Wilkinson-like kinetics was used to describe the experimental results which were governed by the irreversible attack of free DMI at the rhodium complex. The activation energy of the ratedetermining step is 53 kJ mol -1 and is similar in both systems.

The hydrogenation of itaconic acid and dimethyl itaconate is transferred from methanol to aqueous micellar solutions of several surfactants, e.g., SDS and Triton X-100, in order to facilitate the recovery of the catalyst. The reaction rate and selectivity strongly depends on the chosen surfactant and in some cases also on the surfactant concentration. In the best case the selectivity is the same as in methanol but the reaction rate is still lower because of a lower hydrogen solubility in water. Repetitive semi-batch experiments are chosen to demonstrate that high turn-over-numbers (.1000) can be reached in aqueous micellar solutions. No notable catalyst deactivation is observed in these experiments. The performance of micellar reaction systems is controlled by the partition coefficient of the substrates between the micelles and the continuous aqueous phase which can be predicted using the Conductor-like Screening Model for Real Solvents (COSMO-RS).

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-4diphenylphosphino-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.

The effect of the P/Rh ratio and the surfactant concentration on the partial hydrogenation of sunflower oil in Triton X-100 microemulsion systems with the watersoluble catalyst complex Rh-TPPTS has been studied. An unusual hindering effect of the surfactant on the production of elaidic acid and stearic acid as the oil is hydrogenated was observed. When increasing the concentration of Triton X-100 in the reaction medium from 3 to 15 wt%, the content of elaidic acid and stearic acid were lowered 21 and 34%, respectively. The maximum content of oleic acid was attained when the concentration of Triton X-100 was 15 wt%, obtaining a high content of 51.8% of oleic acid. When the ligand/metal ratio was higher, the reaction was slower but more selective to oleic acid. The Rh-TPPTS catalyst could be recycled up to 3 times after hydrogenation of sunflower oil by extracting the oil phase of a three-phase microemulsion system, observing a continuous deactivation of the catalyst.