Removal of rhodium catalyst from HNBR solution

摘要

This paper is concerned with a novel process for removal of the metal rhodium catalyst from HNBR solution by using the compound and the extraction. The process comprises treating the solution with thiourea and formic acid, followed by isolating the two phases. Optimum conditions for removal of rhodium and effective compound-extraction system were determined by experiments. 15 moles of ethanol solution of thiourea were used with one mole Rh catalyst; and an 88% formic acid solution was used as the extraction reagent, with double volumetric amount of polymer solution. The extraction reaction was maintained at 110～120℃ for 2 hours. In the end, the recovery rate of Rhodium as determined by atomic absorption spectroscopy was about 97.5%.