Ureido-modified macroporous hollow silica microspheres for recovery of Wilkinson's catalyst in hydrogenated nitrile butadiene rubber

Abstract Hydrogenated nitrile butadiene rubber (H-NBR), which is obtained by the selective hydrogenation of nitrile butadiene rubber (NBR), has attracted great interests in many industrial fields. However, the recovery of the catalyst remains a challenge in the homogeneous catalytic hydrogenation of NBR, restricting its industrial production. In the present work, ureido-modified macroporous hollow silica microspheres were designed for the recovery of the Rh-based catalyst, with Wilkinson's catalyst (RhCl(P(C 6 H 5 ) 3 ) 3 ) as an example, in the homogeneous catalytic hydrogenation of NBR. After the effects of the adsorbent loading, adsorption parameters (temperature, agitating speed and time), and separation condition (centrifugal speed and time) on the Rh recovery rate were optimized in detail, a maximum Rh recovery rate of 92.2% was achieved.