Mass Transfer and Drop Size Distributions in Reactive Nanoparticle‐Stabilized Multiphase Systems

Abstract

Mass transfer in stirred liquid-liquid systems with and without silica nanoparticles is investigated for the saponification of benzoyl chloride. The mass transfer area is positively affected by the nanoparticles which lead to an increase of the liquidliquid interfacial area due to droplet coalescence hindrance. However, an additional mass transfer resistance induced by particles at the liquid-liquid interface was observed for all particle concentrations, since the high occupancy diminishes the available area for mass transfer. The ratio of the two oppositional effects needs to be determined to identify suitable nanoparticle reaction systems.

Influence of Different Silica Nanoparticles on Drop Size Distributions in Agitated Liquid‐Liquid Systems

“…Dugyala et al investigated aqueous suspensions with 1 wt % silica nanoparticle against decane and reported only a slight decrease of the interfacial tension by 0.5 mN m −1 . Similar results were also found in water/1‐dodecene/HDK H20 systems under the condition that the oil phase does not contain any surface‐active impurities . These results are in agreement with the interfacial tension values shown in Fig.…”

Description of Disperse Multiphase Processes: Quo Vadis?

“…shows the increasing viscoelasticity and, therefore, increasing resistance against deformation of a liquid/liquid interface with rising concentration of an additive, in this case silica nanoparticles. The SEM image shows the interlocking nanoparticles at the liquid/liquid interface, which do not affect the liquid/liquid interfacial tension but hinder the drop/drop coalescence . This leads to long‐term stability and so‐called arrested coalescence in Pickering emulsions and also influences mass transfer processes .…”

“…The SEM image shows the interlocking nanoparticles at the liquid/liquid interface, which do not affect the liquid/liquid interfacial tension but hinder the drop/drop coalescence . This leads to long‐term stability and so‐called arrested coalescence in Pickering emulsions and also influences mass transfer processes . Measurements of shear rates with interfacial rheometers provide another direct measurement of the mechanical strength of the interface, but necessitate high torque sensitivity , .…”

“…Spinning drop measurements of increasing viscoelasticity due to the presence of additives at the liquid/liquid interface (here: silica nanoparticles HDK H20, water, 1‐dodecene (according to ).…”

“…Within the different solvent systems, the requirements vary significantly, e.g., coalescence in a decanter is intended in a phase separation step in micellar and thermomorphic solvent systems whereas it should be prevented in nanoparticle‐stabilized emulsions where droplets are separated from the bulk phase by ultrafiltration. The measurement techniques used to monitor the swarm behavior, reaction performance and system characteristics range from (cryogenic) scanning electron microscopy (SEM) , and endoscopes and phase contrast magnetic resonance imaging (PC‐NMR) to inductively coupled plasma optical emission spectroscopy (ICP‐OES) , .…”