A general phase-transfer protocol for mineral acids and its application in the large-scale synthesis of highly nanoporous iron phosphate in nonaqueous solvent

As a general protocol for transferring mineral acids from an aqueous solution to an organic phase, mineral acids are extracted with secondary carbon primary amine (C _9-11) ₂CHNH ₂ (commercial code: N1923) into an organic phase (e.g., heptane or benzene) because of the complexation reaction and the formation of typical reversed micelles. Based on this principle, a novel approach for a large-scale synthesis of highly nanoporous iron phosphate particles is developed via the formed RNH ₃ ⁺/H ₂PO ₄ ^- (H ₂O)/oil reversed micelle system and ethanol-Fe ³⁺ solutions. Synthetic conditions, such as H ₃PO ₄ concentration in reversed micelles and Fe ³⁺ concentration in ethanol-Fe ³⁺ solution are investigated and optimized. The product is characterized using transmission electron microscopy, Brunauer-Emett-Teller, thermogravimetric analysis, X-ray diffraction, and Fourier transform infrared spectroscopy. The as-obtained iron phosphate is flocculent and highly porous, exhibiting a high reported surface area of 144 m ²/g. The synthetic procedure is relatively simple and is suitable for large-scale fabrication, and the used organic amines can be recycled. The power of this approach is demonstrated using other kinds of organic amines, such as tri-n-octylamine (TOA) and tri-C _8-10-alkylmethyl ammonium chloride (N263), as phase-transfer reagents exhibiting promising application in the synthesis of highly nanoporous materials.