Abstract

In the present research, the eggshell as a hazardous waste by European Union regulations was converted to a valuable catalyst, namely nano-Fe₃O₄@(HSO₄)₂. The as-prepared catalyst, first, was characterized using different techniques, including Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), field emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM). Back-titration method confirmed the loading of a high surface density of acidic group, namely 8.8 mmol HSO₄ per gram of the catalyst. The catalytic property of the as-prepared catalyst was examined in the synthesis of 2-amino-3-cyanopyridines via anomeric-based oxidation (ABO), and hexahydroquinolines derivatives. High yield, short reaction time, solvent-free condition, waste to wealth, and optimization with the design of experiment are the major advantages of the present work. Taken together, these results suggest the conversion of waste to wealth products around the world and usage in organic transformation.

Graphic abstract

摘要

在本研究中，根据欧盟法规，作为危险废物的蛋壳被转化为有价值的催化剂，即纳米Fe ₃ O ₄ @（HSO ₄）₂。首先，使用不同的技术对制得的催化剂进行表征，包括傅立叶变换红外光谱（FT-IR），X射线衍射（XRD），能量色散X射线光谱（EDX），场发射扫描电子显微镜（FESEM）和透射电子显微镜（TEM）。反滴定法确认了酸性基团的高表面密度，即8.8 mmol HSO ₄的负载每克催化剂。在通过基于端基的氧化（ABO）和六氢喹啉衍生物合成2-氨基-3-氰基吡啶的过程中，检查了所制备催化剂的催化性能。高收率，较短的反应时间，无溶剂条件，变废为宝以及通过实验设计进行优化是本研究的主要优点。综上所述，这些结果表明世界范围内已将废物转化为财富产品，并用于有机转化。

图形摘要