Microemulsion Systems with Rhodium Tris(3‐sulfophenyl)phosphine Trisodium Salt Complex for Product Isolation and Catalyst Recycling in the Hydrogenation of Dimethyl Itaconate

Abstract

AbstractMicroemulsion systems with the nonionic surfactant p‐tert‐octylphenoxy polyethoxyethanol (OP9.5EO), the anionic surfactant dioctyl sulfosuccinate sodium salt (DOSS) and the narrow range nonionic surfactant alkyl polyethylene glycol ether (C10EO5) were used as solvent systems in the catalytic hydrogenation of dimethyl itaconate (DMI) catalysed by the water soluble catalyst complex Rh‐TPPTS in order to achieve product isolation and catalyst recycling. The DOSS systems, which are more sensitive to the substrate and catalyst addition allowed for the hydrogenation to proceed with an initial hydrogenation rate about three times higher than with the nonionic surfactants, when the surfactant concentration was 15 wt%. Systems with 3 wt% surfactant were used in order to accomplish catalyst recycling. With a biphasic DOSS mixture a turnover number (TON) of 1,200 mol of DMI hydrogenated per mol of catalyst (Rh) was obtained in 3 consecutive runs. A three‐phase system for the OP9.5EO mixture allowed the catalyst to be recycled 3 times and a TON of 1,500 in 4 runs was obtained. A TON of 800 in 2 runs was obtained using a three‐phase C10EO5 mixture.