杂环化聚丙烯亚胺树状聚合物负载钌铑双金属纳米粒子的制备及在催化丁腈橡胶氢化中的应用

摘要

A series of Ru/Rh bimetallicdendrimer-stabilized nanoparticles [ Gn-M ( Rux Rh100-x ) DTNs, x:mole molar fraction of Ru ] was prepared by complexing-reducing method with the 15-membered azamacrocycles-terminated poly ( propylene imine ) dendrimer ( Gn-M, n=2, 3, 4 ) as template. These bimetallic DTNs were used as catalysts for the hydrogenation of nitrile-butadiene rubber( NBR) . The results of UV-Vis spectroscopy( UV-Vis) , X-ray diffraction( XRD) and energy dispersive spectrum( EDS) indicated that bimetallic ions were successful reduced and stabilized by Gn-M. Particle size analysis showed that the average size of G2-M(Ru50Rh50), G3-M ( Ru50 Rh50 ) and G4-M ( Ru50 Rh50 ) DTNs were 7. 5, 8. 1 and 4. 5 nm, respectively. G4-M( Ru30 Rh70 ) DTNs catalyst reached the maximum hydrogenation degree( HD) of 99. 51%, and the results of gel fraction measurement and 1 H nuclear magnetic resonance ( 1 H NMR ) indicated that Ru/Rh DTNs were highly selective for the catalytic hydrogenation of NBR. Moreover, the HD can still reach 90. 58% after twice recycle.%以十五元三烯氮杂大环改性的不同代数聚丙烯亚胺树状聚合物(Gn-M,n=2,3,4)为模板,通过共络合-还原方法制备了一系列钌/铑双金属纳米粒子[Gn-M(Rux Rh100-x)DTNs,x为Ru摩尔分数],并将其应用于丁腈橡胶(NMR)的催化氢化.用紫外-可见光谱(UV-Vis)、X射线衍射分析(XRD)及X射线能谱(EDS)表征DTNs的金属组成和结构,结果表明,DTNs上的双金属离子被还原成金属单质并负载于Gn-M上;粒度分析结果表明,G2-M(Ru50Rh50),G3-M(Ru50Rh50)和G4-M(Ru50Rh50)DTNs的平均粒径分别为7.5,8.1和4.5 nm.凝胶测试及核磁共振波谱(1 H NMR)结果表明,Ru/Rh DTNs催化剂对丁腈橡胶的催化氢化反应具有良好的选择性.当以G4-M(Ru30 Rh70)DTNs为催化剂时,NBR的氢化度最高可达99.51%,循环使用2次后,丁腈橡胶的氢化度仍可达到90.58%.