Continuous-flow Synthesis of Ruthenium Nanoparticles using a Microreactor for the Selective Hydrogenation Reaction

In this study, a continuous flow reactor was used to synthesize Ru nanoparticles with a well-distributed size and good stability. The effects of reactant dilution and flow rate on the synthesis were investigated, and it was found that optimization of these parameters was critical in obtaining small-sized Ru nanoparticles using a solution of 0.00025 M RuCl3.3H2O and 0.001M NaBH4 at a flow rate of 30mL/h. The Ru nanoparticles obtained were coated with CTAB surfactant, which was confirmed by TEM and PSD studies. The interaction between the surfactant and the nanoparticles was also confirmed by FTIR analysis. The synthesized Ru nanoparticles were then tested for their catalytic activity in high-pressure alkene hydrogenation and were found to be effective in producing the corresponding hydrogenated products in good yields. Furthermore, the catalytic effect of Ru nanoparticles was utilized for the synthesis of two natural products, brittonin A and dehydrobrittonin A. Both products were successfully isolated in measurable yields. This synthesis protocol had several advantages, including low catalyst loading, no use of additives, wide substrate scope, simple product separation, and catalyst recovery up to 8 times. Overall, this study demonstrated the potential of continuous flow reactor technology for synthesizing stable and well-distributed nanoparticles, and the effectiveness of Ru nanoparticles as catalysts in various chemical reactions. The study's findings have important implications for the development of more efficient and sustainable chemical synthesis protocols.