Natural Seashell Waste as an Efficient and Low‐Cost Catalyst for the Synthesis of Arylmethylenemalonitriles

Abstract

In this work, four kinds of natural seashells (clam shell, oyster shell, scallop shell, and conch shell) are investigated as catalysts for the Knoevenagel reaction to produce arylmethylenemalonitriles, among which conch shells show the highest catalytic activity due to their mixed phases of calcite and aragonite, resulting in the relatively weak base strength and fewer number of basic sites. Solvent effect and catalyst usage are systematically investigated, and conch shells show high universality for nine aromatic aldehydes to produce the desired products with high yield in short time under optimized conditions. In addition, this catalyst possesses good recyclability and could be used four times without obvious deactivation. In all, conch shell is an efficient, low‐cost, green, and recyclable catalyst for the Knoevenagel reaction.

Investigation of the structure and hardness properties of Anodonta anatina mussel shells

“…Freshly prepared dry shells from four different, undamaged, mature, and healthy specimens were ground into powder using a mortar and pestle for XRF analysis. The crushed mussel shells were then calcined at 900°C for 3 hours, with a heating rate of 5°C/min, to determine the amount of calcium oxide (CaO) present (Gao et al, 2019;Moustafa et al, 2015).…”

Fine Characterization of Natural SiO2-Doped Catalyst Derived from Mussel Shell with Potential Photocatalytic Performance for Organic Dyes

“…Although composite photocatalysts have achieved significant improvements compared to the mono-component photocatalysts, industrial applications of these photocatalysts are still challenging, especially in terms of their mass production, cost, and stability that need to be addressed. Thus, in recent years, researchers have been focusing on cheap and efficient photocatalysts, especially those from natural biomaterials with multiple scales and hierarchical morphologies, such as pollen [21], rice straw [22], kelp [23], seashells [24], etc.…”