Catalytic application of SO₄²⁻/Fe–ZrO₂nanoparticles synthesized by a urea hydrolysis method for environmentally benign one pot synthesis of 1,8-dioxodecahydroacridines

Abstract

A series of Fe 2 O 3 -ZrO 2 mixed oxides (FexZr) were prepared by colloidal precipitation method using urea as mild hydrolyzing agent. The sulfate ions were grafted onto the surface of the mixed oxide by treatment with dilute sulfuric acid and subsequent thermal activation. The resulting sulfated grafted mixed oxides (SFexZr) were characterized using XRD, FTIR, Raman, surface area measurement, UV-Vis, XPS, TPD, FESEM and HRTEM techniques. XRD study indicated formation of a substitutional type solid solution in a limited composition range due to incorporation of iron ions into the zirconia lattice. The selective stabilization of the tetragonal phase of zirconia was observed in the mixed oxide system. The microstructural properties of the sulfate grafted mixed oxide were obtained from the Fourier analysis of the broadened XRD profiles. The presence of well dispersed iron oxide species in the zirconia lattice was ascertained from the Raman and UV-Vis study. XPS and FTIR study confirmed the presence of grafted sulfate functional groups. HRTEM analysis of the SFe10Zr sample revealed the presence of well dispersed mixed oxide particles with size in the range of 10-30 nm. The catalytic activity of the SFexZr material was evaluated for the synthesis of 1,8-dioxo-decahydroacridines by multicomponent condensation of dimedone, substituted aryl aldehyde and substituted anilines. A variety of dioxodecahydroacridines molecules were obtained with high yield and purity. The SFe10Zr material exhibited high surface area, enhanced sulfur retention and excellent catalytic activity for synthesis of the 1,8-dioxo-decahydroacridines molecules.

Ba/ZrO2 nanoparticles as efficient heterogeneous base catalyst for the synthesis of β-nitro alcohols and 2-amino 2-chromenes

“…ZrO 2 is a direct band gap insulator which shows an interband transition in the UV region of the spectrum. [41][42][43] The monoclinic form of ZrO 2 has two direct interband transitions at 5.93 and 5.17 eV, whereas the tetragonal form has a band gap of 5.1 eV. 41 In the present case, the peak at 214 nm can be assigned to the O 2− → Zr 4+ charge transfer transition arising from the host zirconia matrix (figure 6 I).…”

“…The stabilization of the tetragonal phase in zirconia sample has been a subject of intense study in literature. [38][39][40][41][42][43] The tetragonal phase being metastable in nature undergoes a martensitic transformation to the monoclinic phase. 41 The presence of aliovalent impurities in zirconia structure as well as surface modification by ionic species selectively stabilizes the tetragonal phase.…”

“…41 The presence of aliovalent impurities in zirconia structure as well as surface modification by ionic species selectively stabilizes the tetragonal phase. [40][41][42][43] The aliovalent dopants such as Fe 3+ ions induce oxygen ion vacancy in the zirconia lattice which in turn helps in the stabilization of tetragonal phase. 41,43 The surface modification process on the other hand reduces the grain boundary area among the zirconia particles preventing the mobility of ions during phase transformation.…”

“…[40][41][42][43] The aliovalent dopants such as Fe 3+ ions induce oxygen ion vacancy in the zirconia lattice which in turn helps in the stabilization of tetragonal phase. 41,43 The surface modification process on the other hand reduces the grain boundary area among the zirconia particles preventing the mobility of ions during phase transformation. 42 It has also been reported that there is a critical crystallite size of zirconia below which the tetragonal phase is stabilized.…”

Acridine‐1,8‐diones: Synthesis and Biological Applications

“…[92] Simple technique, green reaction media, diverse functional utility, magnetically recovered and reusable catalyst are the additional advantages of the present methodology [Scheme 11, Method 3]. Pradhan and Mishra [93] synthesized SO 4 2À /Fe-ZrO 2 nanoparticles using colloidal precipitation method, where sulfate ions were fabricated on the surface of mixed oxides and further studied their catalytic efficiency on acridinediones synthesis using MeCN solvent. The authors also evaluated the effect of Fe Firstly, Rahmani and coauthors [94] demonstrated the applicability of nano titanium dioxide as an proficient and recyclable heterogenous catalyst for the synthesis of variety of 1,8dioxodecahydroacridines in excellent yields via simple procedure [Scheme 12, Method 1].…”