Ruthenium silicate (RS-1) zeolite: novel heterogeneous efficient catalyst for synthesis of 2-arylbenzothiazole derivatives

Abstract

Mesoporous silicate and transition metal (Ru+3) containing mesoporous silicate materials or ruthenium silicate Ru+3/Si+4 where synthesis by using hydrothermal process. Mesoporous ruthenium silicate (RS-1) and zeolite catalyst have been successfully synthesized with variable molar ratio such as (a) Ru:Si 1:100, (b) Ru:Si 1:150, (c) Ru:Si 1:200. The elemental composition, structural morphology, crystal phase and properties and various parameters of the catalyst were examined by Fourier transform infrared spectroscopy, scanning electron microscopy, powder X-ray diffraction. Energy dispersive X-ray pattern/spectroscopy analysis EDX/EDS, where as the activity of obtained catalysts was tested in the Willgerodt–Kindler synthesis between 2-aminothiophenol and substituted aryl aldehyde (1:1 mol) to form a 2-arylbenzothiazole. The novelty of the presented work was the ruthenium (Ru+3) metal impregnations in silicate framework for the synthesis of novel ruthenium silicate (RS-1) zeolite as a catalyst and the investigation of the various parameters, role, its stability and catalytic activity in the Willgerodt–Kindler (combined both Knovenagel and Maichel addition reaction) synthesis. The developed protocol has several benefits such as short reaction time, mild reaction condition, and good reusability of catalyst.