Silica-coated magnetic NiFe2O4 nanoparticles-supported H3PW12O40; synthesis, preparation, and application as an efficient, magnetic, green catalyst for one-pot synthesis of tetrahydrobenzo[b]pyran and pyrano[2,3-c]pyrazole derivatives

• Published in: Research on chemical intermediates 2016-04, Vol.42 (4), p.3071-3093
• Main Authors: Maleki, Behrooz, Eshghi, Hossein, Barghamadi, Mohammad, Nasiri, Negar, Khojastehnezhad, Amir, Sedigh Ashrafi, Samaneh, Pourshiani, Omid
• Format: Article
• Language: English
• Subjects: Catalysis; Chemistry; Chemistry and Materials Science; Inorganic Chemistry; Physical Chemistry
• ISSN: 0922-6168; 1568-5675
• DOI: 10.1007/s11164-015-2198-8

A powerful, magnetic, supported, acid catalyst, NiFe 2 O 4 @SiO 2 –H 3 PW 12 O 40 , was prepared by chemical support of Keggin (H 3 PW 12 O 40 ) heteropolyacid (HPA) on silica-coated NiFe 2 O 4 magnetic nanoparticles. XRD, TEM, SEM, VSM, and FTIR confirmed that the keggin HPA is well dispersed on the surface of silica-coated NiFe 2 O 4 magnetic nanoparticles. The magnetically recoverable catalyst could be easily recycled at least six times without significant loss of catalytic activity. After full characterization, its catalytic activity was investigated in the synthesis of tetrahydrobenzo[ b ]pyran and pyrano[2,3- c ]pyrazole derivatives. Graphical Abstract (1) Novel silica-coated magnetic NiFe 2 O 4 nanoparticles-supported H 3 PW 12 O 40 was fabricated and characterized. (2) Recyclability of the catalyst. (3) Avoiding use of corrosive acid catalysts. (4) Green chemistry.