Sulphated alumina tungstic acid (SATA): a highly efficient and novel heterogeneous mesostructured catalyst for the synthesis of pyrazole carbonitrile derivatives and evaluation of green metrics.

A novel mesostructured catalyst sulphated alumina tungstic acid (SATA) has been prepared by an easy route. Various techniques such as IR, XRD, SEM, EDX, TEM, TGA and BET were used to characterize the synthesized catalyst. The catalytic activity of the meso material has been explored by synthesizing a series of new pyrazole carbonitrile derivatives from aromatic aldehydes, ethylcyanoacetate, phenylhydrazine/hydrazine hydrate in ethanol under reflux conditions. Furthermore, the "greenness" of this protocol when estimated by green metrics, displayed satisfactory results. The protocol is free from column chromatography, and toxic solvents and is more efficient as compared to reported ones.

Design, characterization and catalytic evaluation of halometallic ionic liquid incorporated Nd2O3 nanoparticles ([smim][FeCl4]-@Nd2O3) for the synthesis of N-aryl indeno pyrrole derivatives.

Silica modified imidazolium [smim] based halometallic ionic liquids, [smim][MCl4] (M = Fe, Cu and Zn), were synthesized for the evaluation of acidic and catalytic properties. Among these ILs, [smim][FeCl4]- was used for the preparation of heterogeneous catalyst ([smim][FeCl4]-@Nd2O3) by simple immobilization of IL on Nd2O3 nanoparticles. The structure of [smim][FeCl4]-@Nd2O3 was established by various techniques including FTIR, Raman, UV-vis DRS, powder XRD, SEM/EDX, elemental mapping, TEM, TGA, EPR and XPS analyses. The stability of nano-catalyst, [smim][ FeCl4]-@Nd2O3, was established with the help of zeta potential analysis which showed a value of -40.32 mV lying under the stability range. Potentiometric titration with n-butyl amine was used to evaluate the acidic properties of [smim][MCl4] as well as [smim][FeCl4]-@Nd2O3. The catalytic potential of the material was probed through the one pot synthesis of N-aryl indeno pyrrole derivatives. The results showed excellent performance of the material by producing a high yield (98%) of indeno pyrrole derivatives. A recyclability experiment revealed that the catalyst was efficient in up to five cycles with insignificant loss in catalytic activity. The evaluation of green metrics indicated the sustainability of the present protocol in terms of high atom economy and low E-factor.

Sulfonic acid functionalized metal-organic framework (S-IRMOF-3): a novel catalyst for sustainable approach towards the synthesis of acrylonitriles.

A sulfonic acid functionalized metal-organic framework (S-IRMOF-3) has been synthesized by dropwise addition of chlorosulfonic acid (0.5 mL) in IRMOF-3 (1 g) containing 20 mL of CHCl3 at 0 °C under simple stirring. The catalyst was applied in Knoevenagel condensation of various aromatic and hetero-aromatic aldehydes forming acrylonitrile derivatives. The catalyst was characterized thoroughly by using FT-IR, XRD, 13C MAS NMR, SEM, EDX, elemental mapping, TEM, BET, NH3-TPD and TGA/DTA techniques. The presence of characteristic bands at 1694 cm-1, 1254-769 cm-1 and 1033 cm-1 in the FT-IR spectrum, 2θ ≃ 6.7° and 9.8° in the XRD pattern and δ = 31.79, 39.55, 129.61, 131.46 (4C, CH), 133.54, 140.07 (2C), 167.71, 171.47 ppm (2C, 2C[double bond, length as m-dash]O) in the solid state 13C MAS NMR spectrum confirmed the successful formation of catalyst. This new eco-friendly approach resulted in a significant improvement in the synthetic efficiency (90-96% yield), high product purity, and minimizing the production of chemical wastes without using highly toxic reagents for the synthesis of acrylonitriles with selectivity for (Z)-isomer. Steric interactions seem to have an influence on the control of the Z-configurational isomers. By performing DFT calculations, it was found that the (Z)-isomer 3a is stabilized by 1.64 kcal mol-1 more than the (E)-isomer. The catalyst could be reused for five consecutive cycles without substantial loss in catalytic activity.