Preparation, Characterization and First Application of Alumina Supported Polyphosphoric Acid (PPA/Al₂O₃) as a Reusable Catalyst for the Synthesis of 14-Aryl-14H-dibenzo[a, j]xanthenes

Abstract

Alumina supported polyphosphoric acid (PPA/Al 2 O 3 ) was successfully prepared by impregnation of alumina support by polyphosphoric acid and characterized using FT-IR spectroscopy, the N 2 adsorption/desorption analysis (BET), thermal analysis (TG/DTG), and X-ray diffraction (XRD) techniques. The catalytic behavior of this new solid acid supported heterogeneous catalyst was checked in the synthesis of 14-aryl-14H-dibenzo[a, j]xanthenes by cyclocondensation reaction of β-naphthol and aryl aldehydes under solvent-free conditions. The results showed that the novel catalyst has high activity and the desired products were obtained in very short reaction times with high yields. Moreover, the catalyst can be easily recovered by filtration and reused at least three times with only slight reduction in its catalytic activity.

Preparation, Characterization and First Application of Aerosil Silica Supported Acidic Ionic Liquid as a Reusable Heterogeneous Catalyst for the Synthesis of 2,3-Dihydroquinazolin-4(1H)-ones

“…In most of these cases, the supported catalysts so prepared could provide advantages over their unsupported counterparts in terms of separation, reusability, and particularly, the ability to provide practical conveniences in a continuous system that is valued in industry. [5][6][7] In supported catalysts, the catalytic behavior of the catalyst is strongly dependent on support properties. Among the various supported catalysts, particularly, alumina and silica supported reagents have advantages of low cost, ease of preparation, and catalyst recycling.…”

Alumina Supported Acidic Ionic Liquid: Preparation, Characterization, and Its Application as Catalyst in the Synthesis of 1,8-dioxo-octahydroxanthenes

“…As shown, the compound 3d was obtained in moderate yields in H 2 O, CH 3 CN, AcOEt, and EtOH (entries [16][17][18][19], but in high-yield in CH 2 Cl 2 (entry 20) and also in solvent-free conditions (entry 13). Although, there is no significant difference between solvent-free conditions and CH 2 Cl 2 as solvent in the model reaction, based on our investigations, in CH 2 Cl 2 as solvent, the catalyst has poor reusability, but in solvent-free condition, the reusability of [Et 3 NC 4 SO 3 H][HSO 4 ]/Al 2 O 3 was found to be favorable and it could be recovered and subsequently reused several times.…”

“…For showing the effect of solvent, the same model reaction was also carried out in different solvents including H 2 O, CH 3 CN, AcOEt, EtOH, and CH 2 Cl 2 in the presence of 0.2 g of the catalyst ( Table 2, entries [16][17][18][19][20]. As shown, the compound 3d was obtained in moderate yields in H 2 O, CH 3 CN, AcOEt, and EtOH (entries [16][17][18][19], but in high-yield in CH 2 Cl 2 (entry 20) and also in solvent-free conditions (entry 13).…”

“…Among the various supported catalysts, particularly, alumina and silica supported reagents have advantages of low cost, ease of preparation, and catalyst recycling. [15][16][17][18] Xanthenes have received great attention because of their wide range of therapeutic and biological properties, such as antibacterial, [19] antiviral, [20] and anti-inflammatory activities. [21] Apart from their use as valuable synthetic precursors for many organic compounds [22] and dyes [23] they also found uses in laser technologies, [24] and fluorescent materials for visualization of biomolecules.…”

Polymer Support Immobilized Acidic Ionic Liquid: Preparation and Its Application as Catalyst in the Synthesis of Hantzsch 1,4-Dihydropyridines

“…According to this method and due to our interest in the applications of reusable catalysts in organic reactions [40][41][42][43][44][45][46][47] …”