Silica-coated MgAl2O4 nanoparticles supported phosphotungstic acid as an effective catalyst for synthesis of -aminophosphonates

摘要

In this research, a recoverable catalyst (MgAl2O4@SiO2-PTA) was prepared by a simple utilization method. The prepared catalyst was characterized by XRD, FT-IR, SEM, EDX, ICP-AES, and BET techniques. The average crystallite size of MgAl2O4 was calculated to be 40nm by the Debye-Scherrer formula. The nanocomposite was examined as a heterogeneous catalyst for synthesis of -aminophosphonates under solvent-free conditions at room temperature. In this process, magnesium aluminate spinel (MgAl2O4), used as the base and supporting catalyst for H3PW12O40 (PTA), provides the recycling and reusing of the catalyst and also increases the efficiency of the reaction, which is due to the increase in the surface/volume ratio. In order to obtain optimal conditions, the synthesis of -aminophosphonates reactions was investigated with different solvents and catalysts. The results showed that -aminophosphonate prepared from the benzaldehyde and aniline reaction has higher efficiency and a shorter time than other reactions. The catalyst was recovered by simple filtration, and it can be recycled for at least five successive times without loss of catalytic activity.