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Zhu, Wenxia, et al. Journal of Molecular Liquids 413 (2024): 125925.
Sodium oleate (NaOL), a widely used anionic collector in mineral flotation, often faces limitations in selectively separating minerals with similar surface properties, such as fluorite and calcite. Recent studies have demonstrated that combining NaOL with alkylamides, particularly erucamide, significantly improves flotation selectivity.
Under optimized conditions (NaOL/erucamide molar ratio 10:4, pH 8, dosage 4 × 10⁻⁵ mol/L), the flotation recovery difference between fluorite and calcite exceeded 50%, far surpassing the performance of NaOL alone. Surface tension and fluorescence spectroscopy analyses revealed that the mixed collector system exhibited greater surface activity and a stronger tendency to form micelles in solution, indicating a synergistic interaction between NaOL and alkylamides.
X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) confirmed that the introduction of alkylamides enhanced adsorption selectivity. The amine groups in alkylamides facilitated stronger hydrogen bonding with fluorine atoms on the fluorite surface, resulting in higher adsorption density and stronger hydrophobic interactions compared to calcite. This dual mechanism-hydrophobic chain extension and functional group-specific bonding-was key to improving mineral separation efficiency.
These findings highlight sodium oleate's adaptability when paired with tailored co-collectors, offering an effective strategy for challenging mineral separation systems. The approach provides a valuable reference for designing flotation reagents to address selectivity issues in mineral processing industries.
Singh, Ravi Pratap, et al. Tetrahedron Letters 137 (2024): 154930.
Sodium oleate, an anionic surfactant, has demonstrated remarkable utility in facilitating palladium-catalyzed hydroxycarbonylation reactions under mild aqueous conditions. In a recent study, aryl iodides were efficiently converted into aryl carboxylic acids, as well as their amide and ester derivatives, using Pd(OAc)₂ as catalyst, sodium oleate (0.16 M) as surfactant, and water as the reaction medium.
The optimized protocol achieved quantitative conversion of 1-iodo-4-nitrobenzene to 4-nitrobenzoic acid at ambient temperature and atmospheric CO pressure, with yields up to 90%. Notably, lowering the palladium catalyst loading to 1 mol% maintained high efficiency at normal temperature and pressure, though prolonged reaction time was required. Among tested bases, N,N-diisopropylamine (DIPEA) afforded the best results.
The role of sodium oleate is pivotal-it forms micellar structures in aqueous media, enhancing the solubilization of hydrophobic aryl iodide substrates and improving mass transfer between the organic reactants and the aqueous catalytic environment. This micellar effect enables high reactivity without organic solvents, aligning with principles of green chemistry.
This method exhibited broad substrate tolerance, accommodating electron-rich, electron-deficient, and multi-substituted aryl iodides. Moreover, its applicability to one-pot synthesis of amides and esters, as well as drug-like molecules such as niacin and mefenamic acid analogues, underscores sodium oleate's value in pharmaceutical-oriented synthetic chemistry.
By combining micellar catalysis with palladium chemistry, sodium oleate enables sustainable, high-yield carbonylation reactions under operationally simple, eco-friendly conditions.
Wang, Jing, et al. Journal of Environmental Chemical Engineering (2025): 116887.
Sodium oleate (SOL), an anionic surfactant, has been successfully applied to hydrophobically modify electrolytic manganese residue (EMR), offering an effective approach to reduce its high moisture content-a critical challenge in the sustainable development of the electrolytic manganese industry.
Under optimized conditions (100 g SOL per ton EMR, pH 7.6, 50 °C, 1.5 h), the water content of EMR decreased from 32.67 % to 27.88%. The modification increased the contact angle from 0° (superhydrophilic) to 74.25°, enhanced the filtration rate from 5.29 mL·min⁻¹ to 18.65 mL·min⁻¹, reduced surface tension from 73.01 mN·m⁻¹ to 58.23 mN·m⁻¹, and lowered the work of adhesion from 146.02 mJ·m⁻² to 89.24 mJ·m⁻².
Mechanistically, SOL's hydrophobic methyl (-CH₃) and methylene (-CH₂-) groups adsorb onto EMR particle surfaces, shifting them from strongly hydrophilic to hydrophobic. This modification reduces both the surface tension of the slurry and the residual moisture during the manganese ore leaching process.
Application trials in different leaching stages revealed that SOL's moisture-reducing effect followed the order: process 4 (post-leaching pH 7 adjustment with NH₃·H₂O) > process 3 (pH 3 adjustment with CaCO₃) > process 2 (post-H₂SO₄ leaching) > process 1 (pre-leaching).
This study demonstrates sodium oleate's potential as a cost-effective, scalable additive for source-based emission reduction and process water management in manganese hydrometallurgy.
