Catalysis with Soluble Hybrids of Highly Branched Macromolecules with Palladium Nanoparticles in a Continuously Operated Membrane Reactor

The continuous recovery and recycling of soluble metal nanoparticles by means of ultrafiltration is described, employing hybrids of palladium nanoparticles with highly branched amphiphilic polyglycerol as a catalyst for cyclohexene hydrogenation as a model reaction. In a continuously operated membrane reactor a productivity of 29000 TO over 30 exchanged reactor volumes was observed for nanoparticles of 2.2 nm size, with a maximum rate of 1200 TO h-1. Catalysis by soluble metal complexes can be excluded. After 30 hours of operation, some decrease in activity is observed which is due to deposition of palladium on the ultrafiltration membrane, however this material does not contribute to catalytic activity

Diamines for Polymer Materials via Direct Amination of Lipid- and Lignocellulose-based Alcohols with NH₃

Via an all‐catalytic route, long‐chain diamines were prepared by the catalytic direct amination of long‐chain diols, derived from plant oils. High conversion was achieved with good selectivity, with the amount of nitrile impurities formed suppressed to a low level. From the lignocellulose‐based 5‐hydroxymethylfurfural (5‐HMF), or from bis(hydroxymethyl)furan, 2,5‐bis(aminomethyl)furan (BAMF) was generated. 5‐HMF was converted in a one‐pot, one‐step direct amination and reductive amination using ammonia. In both cases, the reaction proceeded very efficiently. In the combined amination and reductive amination, the H2 concentration is a rate‐limiting factor. Reducing the partial pressure of H2 also shortened the reaction time required significantly. Polycondensation of the long‐chain diamines with long‐chain diacids led to higher molecular weight polyamides, illustrating the quality of the diamines obtained by this synthetic approach as monomers.publishe