Pinky Gogoi

Synthesis of dibenzoxanthene and acridine derivatives catalyzed by 1,3-disulfonic acid imidazolium carboxylate ionic liquids

New members of 1,3-disulfonic acid imidazolium carboxylate ionic liquids [DSIM][X] (where X = [CH3COO]−, [CCl3COO]−, [CF3COO]−) were prepared and characterized by 1H NMR,13C NMR, FT-IR, TGA,UV-vis and elemental analysis. The more acidic ILs [DISM][CCl3COO] and [DSIM][CF3COO] were efficiently utilized as recyclable catalysts for the preparation of 14H-dibenzo[a,j]xanthene and 1,8-dioxo-decahydroacridine derivatives in short times under solvent-free conditions at 80–100 °C with excellent yields. The above two ILs could be effectively utilized as catalysts for the synthesis of 1,8-dioxo-decahydroacridine in water at the same temperature.

Studies on Structural Changes and Catalytic Activity of Y-zeolite Composites of 1,3-disulfoimidazolium trifluoroacetate Ionic Liquid (IL) for Three Component Synthesis of 3,4-dihydropyrimidinones

This report describes the development of six acidic composites of Y-zeolite with 1,3-disulfoimidazolium trifluoroacetate [Dsim][CF3COO] ionic liquid (IL) and displays the gradual increase of acidic IL mediated dealumination within zeolite framework with increasing loading in Powder XRD and IR studies. The structural changes of modified framework of zeolite were analyzed by SEM-EDX, TEM, TGA, BET and UV–Vis techniques. Out of the six composites, the more acidic [Dsim][CF3COO]/NaY = 20% (e) composite was evaluated as heterogeneous catalyst for multicomponent synthesis of 3,4-dihydropyrimidinones (DHPMs) under neat condition at various temperature.Graphical Abstract

1,3-Disulfoimidazolium chloronickellate immobilized HZSM-5 framework as visible-light-induced heterogeneous photocatalyst for advanced oxidation process

Ionic solid 1,3-disulfoimidazolium chloronickellate [Dsim]2[NiCl4] with low band gap value can be modified as a heterogeneous photocatalyst after immobilization on siliceous zeolite HZSM-5. In this study, different percentages of [Dsim]2[NiCl4]/HZSM-5 supported ionic systems were prepared as acidic solid materials via wet impregnation. The structural changes of the parent HZSM-5 framework within the heterogenized materials were studied using IR, UV, SEM-EDX, PXRD, Raman, BET, TGA, Hammett acidity, HRTEM and ICP-OES techniques. Assessment of their thermal and water tolerance and intensity of photoluminescence spectra instigate the hybrid samples as possible heterogeneous photocatalysts for oxidative degradation of model dye compound methylene blue (MB) involving H2O2 and sunlight at ambient temperature in aqueous solution. This study may contribute to a new perception for the exploration of halometallate ionic salt systems as potential visible light driven photocatalysts in organic transformation.