Magnetically recoverable, nanoscale-supported heteropoly acid catalyst for green synthesis of biologically active compounds in water

12-Tungstophosphoric acid supported on aerosil silica and silica-coated gamma-Fe2O3 nanoparticles was prepared and characterized using transmission electron microscopy, scanning electron microscopy, and inductively coupled plasma atomic emission spectroscopy. The catalytic activity of the two prepared catalysts was compared in the synthesis of 1,8-dioxo-9,10-diaryldecahydroacridines in water. 12-Tungstophosphoric acid was highly dispersed on the silica-coated gamma-Fe2O3 nanoparticles and showed higher activity and a higher reuse number compared with the acid supported on aerosil silica. The catalyst could be recovered simply by using an external magnetic field and could be reused several times without appreciable loss of its catalytic activity. (C) 2013, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.