Remove Rhodium Catalysts from HNBR Solution

Rhodium complex is excellent catalyst for nitrile-butadiene rubber homogeneous hydrogenation with difficulties in its recovery. A new extraction method for recovery noble metal catalysts from hydrogenated nitrile-butadiene rubber solution was investigated. Rhodium metal catalysts can be efficiently, easily removed from hydrogenated nitrile-butadiene rubber solution using amine as ligand and hydrogen peroxide as oxidant. The condition of removing noble metal catalysts from hydrogenated nitrile-butadiene rubber solution was carefully studied, including oxidant, reaction temperature, and the concentration of amine. The removal rate of the rhodium catalyst over 96% with the optimal conditions.1H-NMR characterization showed that there was no change in the structure and nitrile group of hydrogenated nitrile-butadiene rubber after rhodium catalysts were removed.