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

Ryhan Abdullah Rather,Zeba N Siddiqui,Mohd Umar Khan

doi:10.1039/c9ra09013d

Abstract

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.

Highlights

Various eco-friendly sulfonic acid-based materials have been successfully used as catalysts in organic synthesis[1] due to their higher acidic strength, increased thermal stability, reduced toxicity, etc.[2]
We have developed an easy route for the synthesis of mesoporous sulphated alumina tungstic acid and explored its catalytic activity by synthesizing a series of new pyrazole carbonitrile derivatives via multicomponent reaction
H+ ion concentration of the catalyst was obtained as 0.44 meq. gÀ1 using back titration method

Summary

Introduction

Various eco-friendly sulfonic acid-based materials have been successfully used as catalysts in organic synthesis[1] due to their higher acidic strength, increased thermal stability, reduced toxicity, etc.[2]. We have developed an easy route for the synthesis of mesoporous sulphated alumina tungstic acid and explored its catalytic activity by synthesizing a series of new pyrazole carbonitrile derivatives via multicomponent reaction. The synthesis of catalyst sulphated alumina tungstic acid (SATA) is shown in Scheme 1. To nd out suitable reaction conditions using SATA for the synthesis of pyrazole carbonitriles, various parameters such as different catalysts/solvents, catalyst loading, temperature etc.

Results

Conclusion