Synthesis and characterization of Si-Zr-Mo nanocomposite as a rapid and efficient catalyst for aromatization of Hantzsch 1,4-dihydropyridines

Abstract

Nanocomposite of Silica-zirconia-molybdate designated as Si-Zr-Mo was prepared via the reaction of the in situ generated zirconium-tetra octanoxide [Zr(Oct) 4 ] through condensation of zirconium-tetra-n-butoxide and 1-octanol in a sol–gel method with sulfuric acid and tetraethylorthosilicate (TEOS) followed by grafting of MoO 4 2− on modified silico zirconia nanocomposite under reflux conditions. The prepared nanocomposite was characterized using inductively coupled plasma (ICP), N 2 sorption isotherms, transmission electron microscopy (TEM), and FT-IR spectroscopy. The as prepared nanocomposite had a surface area and pore dimension of 140 m 2 /g and 1.48 nm, respectively. The morphology of sulphated silico zirconia nanocomposite after immobilization MoO 4 2− has been changed from nanoparticles to nanaorods. It was found that the synthesized nanocomposite successfully catalyze the oxidative dehydrogenation of 1,4-dihydropyridines (1,4-DHPs) with 92–100% conversion and 80–100% selectivity toward the desired products.