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The intensification mechanism of aqueous/organic phase reaction by the addition of magnetic polymer nanoparticles was investigated. To understand how nanoparticles intensify the liquid–liquid (L–L) reaction, three reaction enhancement strategies of mechanical agitation (MA), the addition of magnetic polymer nanoparticles (MPN) or phase transfer catalyst (PTC) were compared in Montanari oxidation system. A mass transfer mathematical model was established to describe the oxidation reaction process owing to its inherently fast characteristic of the oxidation of selected substrate (benzyl alcohol). Moreover, the influence of the nanoparticles concentration on the biphasic reaction was explored. The results indicate that the emulsification of nanoparticles is the main reason to intensify the L–L reaction, and the mass transfer specific surface area ( a ow ) is a crucial factor to accelerate the reaction rate. In addition, the emulsion type also plays a significant role to influence the overall mass transfer coefficient ( K ) of substrate. [ABSTRACT FROM AUTHOR]

This work described a general strategy to enhance a typical organic-aqueous heterogeneous green oxidation reaction by introducing surface tunable magnetic nanoparticles into liquids to form a controllable Pickering emulsion. We synthesized cross-linked polystyrene (PS)-covered Fe3O4 nanoparticles grafted with different N-alkyl imidazoles and systematically discussed the effect of surface properties on the formation of emulsions. By loading such particles, the dichloromethane-water-based 2,2,6,6-tetramethylpiperidine-1-oxyl-mediated Montanari oxidation system was converted from the unstable millimeter-scale dispersion into a stable micrometer-scale emulsion, which significantly reduced the reactant transfer distance and resulted in a significantly high overall reaction rate. This reaction efficiency is elucidated in terms of unique properties inherent in an emulsion, including the self-assembly of Fe3O4/PS and Fe3O4/PS[im-C n]Cl ( n=1, 4, 6, and 10) nanoparticles, well ensuring a large specific surface area of the water-oil interface. [ABSTRACT FROM AUTHOR]

The cover picture shows a general strategy to improve the reaction of a typical organic–aqueous heterogeneous green oxidation system, in which surface properties and tunable magnetic nanoparticles were introduced to form a controllable and well‐dispersed emulsion. In their Full Paper, L. Feng et al. reveal that the addition of nanoparticles with proper surface modification can result in improved Montanari reactions compared with the conventional reaction system. The article highlighted by this cover can be found on p. 616 ff. of Issue 4, 2015. [ABSTRACT FROM AUTHOR]