Heteropolytungstate nanoparticles: Microemulsion-mediated preparation and investigation of their catalytic activity in the epoxidation of olefins

• Keggin type Q3PW12O40 nanoparticles were synthesized by using microemulsion system.
• The nanoparticles have uniform size of about 25 nm and spherical morphologies.
• The prepared nanoparticles act as reusable catalyst in the epoxidation of olefins with H2O2.

Keggin type Q3PW12O40 nanoparticles (Q = cetyltrimethylammonium cation) were synthesized in water-in-oil (w/o) microemulsion consisted of water/cetyltrimethylammonium bromide/n-butanol/isooctane. Reaction of Na2WO4, Na2HPO4 and hydrochloric acid within water containing nanoreactors of reverse micelles resulted in the preparation of Q3PW12O40 nanoparticles. The resultant nanoparticles were analyzed by physicochemical methods such as FT-IR spectroscopy, X-ray diffraction, energy-dispersive X-ray analysis, thermogravimetric analyses (TGA-DTA), scanning and transmission electron microscopy and atomic force microscopy which show nearly uniform spherical nanoparticles with size of about 15 nm. Finally, catalytic activity of the Q3PW12O40 nanoparticles was examined in the epoxidation of olefins with H2O2. The prepared nanoparticles acted as recoverable and reusable catalyst in the epoxidation of olefins with H2O2.

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