Ball-milled seashells, as a nano-biocomposite catalyst and natural source of CaCO3 in its aragonite microcrystalline form with fixed CO2, was optimized for the synthesis of isoamyl acetate (3-methylbutyl ethanoate) by response surface methodology with a five-level three-factor rotatable circumscribed central composite design. The seashells nano-biocomposite has proved to be an excellent heterogeneous multifunctional catalyst for the green and environmentally-benign synthesis of isoamyl acetate from acetic acid and isoamyl alcohol under solvent-free conditions. A high yield of 91% was obtained under the following optimal conditions: molar ratio of alcohol: acetic acid (1:3.7), catalyst loading (15.7 mg), the reaction temperature (98 °C), and the reaction time (219 min). The outstanding advantages of this protocol are the use of an inexpensive, naturally occurring and easily prepared nano-biocomposite material having appropriate thermal stability and without any modifications using hazardous reagents, lower catalyst loading and reaction temperature, no use of corrosive Bronsted acids as well as toxic azeotropic solvents or water adsorbents, and simplicity of the procedure.

The preparation, characterization and catalytic application of a novel 1, 3, 5-Tris (2-hydroxyethyl) isocyanurate functionalized graphene oxide is described. The catalyst was characterized by nitrogen adsorption-desorption analysis, scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy. The thermal stability of the material was also determined by thermal gravimetric analysis (TGA). The catalytic application of 1, 3, 5-Tris (2-hydroxyethyl) isocyanurate functionalized graphene oxide nanocatalyst was then investigated in the synthesis of imidazole derivatives from benzil, different aldehydes and ammonium acetate under solvent-free conditions in short reaction times and good to excellent yields. The significant advantages of this procedure are low loading of the catalyst, avoiding the use of toxic transition metals, short reaction times, high to excellent yields, easy separation and purification of the products and reusability of this nanocatalyst.

Ball-Milled seashells, as a nano-biocomposite catalyst and natural source of CaCO3 in its aragonite microcrystalline form and fixed CO2, was optimized for the synthesis of isoamyl acetate by response surface methodology (RSM) with a five-level three-factor rotatable circumscribed central composite design (RCCCD). The seashells nano-biocomposite was proved to be an excellent heterogeneous catalyst for the green and environmentally-benign synthesis of isoamyl acetate from acetic acid and isoamyl alcohol under solvent-free conditions. High yield of 91% was obtained under the following optimal conditions: molar ratio of alcohol: acetic acid (1:3.7), catalyst loading (15.7 mg), the reaction temperature (98°C), and the reaction time (219 min). The outstanding advantages of this protocol are the use of a naturally occurring and easily prepared nano-biocomposite material without any modifications with hazardous reagents, lower catalyst loading and required temperature, avoiding the use of corrosive Bronsted acids as well as toxic azeotropic solvents or water adsorbents, and simplicity of the procedure.

The preparation, characterization and catalytic application of a novel 1, 3, 5-Tris (2-hydroxyethyl) isocyanurate functionalized graphene oxide are described. The catalyst was characterized by nitrogen adsorption-desorption analysis, scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy. The thermal stability of the material was also determined by thermal gravimetric analysis (TGA). The catalytic application of 1, 3, 5-Tris (2-hydroxyethyl) isocyanurate functionalized graphene oxide nanocatalyst was then investigated in the biginelli condensation of different aldehydes with urea and alkylacetoacetates under solvent-free conditions and at moderate temperature. Moreover, the significant advantages of this procedure are the stability, reactivity and reusability of the catalyst, low loading of the catalyst, avoiding the use of toxic transition metals, short reaction times, high to excellent yields, easy separation and purification of the products.