Preparation of facile separable homogeneous Rhodium catalyst and its application for the catalytic hydrogenation of nitrile butadiene rubber and styrene-butadiene rubber

Poly(propylene imine) dendrimer (G2-PPI) terminated by nitrogen-containing triolefinic macrocycle on the periphery (G2-M) was synthesized by a nucleophilic substitution reaction. The structure and composition of G2-M were characterized by FT-IR, H-1-NMR and elemental analysis. The Rh3+ dendrimer-stabilized catalyst (G2-M(Rh3+)) was prepared by utilizing G2-M as stabilizer and analyzed by UV-Vis spectroscopy, H-1-NMR spectrometry, XPS and XRD. G2-M(Rh3+) demonstrates excellent catalytic activity and selectivity for the hydrogenation of nitrile-butadiene rubber (NBR) and styrene-butadiene rubber (SBR), and Rh residue contents for HNBR and HSBR are only 35 and 13 ppm, respectively, without any post treatment.