Preparation, characterization and use of new lignocellulose-based bio nanocomposite as a heterogeneous catalyst for sustainable synthesis of pyrimido benzazoles

Abstract

<p>A sustainable combinatorial synthesis of densely substituted pyrimido [1,2-b] benzazole derivatives in water under microwave irradiation was performed using a new lignocellulose-based bio nanocomposite (BNC) as heterogeneous catalyst. The lignocellulosic waste peanut shells (LCWPS) were turned into a value-added product, a new BNC PS/ZnO, which was prepared <i>via in situ</i> hydrothermal synthesis. The as-prepared BNC was characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy and X-ray diffraction spectrum. PS/ZnO has been successfully used in a sustainable catalytic method for the synthesis of pyrimido [1, 2-b] benzazole derivatives in water under microwave irradiation. The time of this reaction was significantly reduced. This catalytic system has a very high turnover number (TON ∼ 10³) and turnover frequency (TOF ∼ 10⁵h⁻¹). This paper presents the benefit of sustainable management of LCWPS, a bio-sourced polymeric carbohydrate for production of new nanocatalyst.</p