The Preparation of Phosphazene Crosslinked Cyclen Microspheres as Host for Cu2+ Ions and Their Utilization as a Support Material for the Preparation of a Copper Nanocatalyst

摘要

In this study firstly, phosphazene crosslinked cyclen microspheres were synthesized. Then, supported copper nanoparticles were prepared on these phosphazene crosslinked cyclen microspheres for use as a metal catalyst. The prepared microparticles and microparticle-supported metal catalyst were characterized using FT-IR, SEM-EDX, TEM and XPS analysis. Also, the prepared metal composite was used as a catalyst for the reduction reaction of 4-nitrophenol in the presence of NaBH4 in aqueous media. The catalytic activity of the Cu-cyclen composite catalyst was investigated using UV-Vis spectroscopy. The reduction studies were completed at four different temperatures (30-60 A degrees C). The activation parameters were calculated from the obtained rate constants at the four different temperatures (30-60 A degrees C). The activation energy, activation enthalpy and activation entropy for the reduction reaction of 4-NP in the presence of Cu-cyclen composite catalyst were calculated as 39.88, 36.56 and -143.30 kJmol(-1), respectively. The total turnover frequency (TOF) for Cu-cyclen composite catalyst was 0.794 mol 4-NP (mol Cu)(-1) (min)(-1).