An Insight Into The Intensification Of Liquid-liquid Heterogeneous Reaction By The Addition Of Magnetic Polystyrene Nanoparticles

In a liquid-liquid(L-L) heterogeneous reaction system, interfacial area is an important variable in deciding the efficiency of the operation. Traditionally, mechanical agitation, ex-field assistance(such as ultrasonic), the addition of emulsifier or phase transfer catalyst were applied to enhance a heterogeneous reaction rate by strongly mixing the liquids. Recently, the fact that the addition of solid particles forming Pickering emulsion can significantly increase the L-L heterogeneous reaction rate drew a lot of attention. In this paper, the intensification mechanism of aqueous/organic phase reaction by the addition of magnetic polystyrene nanoparticles in Anelli oxidation system was investigated.Firstly, magnetic polystyrene nanoparticles were prepared, and then we added them into Anelli oxidation system to find out how nanoparticles impacted on the reaction. It was found that the Anelli oxidation reaction can be accelerated by the addition of magnetic polystyrene nanoparticles in a wide range of oxidation of alcohols. To understand how nanoparticles intensify the 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 Anelli 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), and the overall volumetric mass transfer coefficient(Kaow) was used to express the efficiency of the oxidation reaction. The results indicated that the formation of Pickering emulsion is the main reason to intensify the L-L reaction, and the mass transfer specific surface area(aow) is a crucial factor to accelerate the reaction rate. In addition, the oil-water interface resistance layer and the emulsion type(W/O) also play a significant role to influence the overall mass transfer coefficient(K) of substrate. Lastly, the influence of the(NaCl concentration, pH, oil/water volume ratio) on the stability of Pickering emulsion was explored.