We investigate aqueous multiphase
systems for catalytic gas/liquid
reactions, namely, the rhodium-catalyzed hydroformylation of the long-chain
olefin 1-dodecene. The multiphase system was formulated from 1-dodecene,
water, and a nonionic surfactant, which increases the solubility between
the two nonmiscible liquid phases. On the basis of these systems,
we present in this paper a transfer of lab experiments (semibatch)
to a successful operation of a miniplant in continuous mode. Under
optimized conditions, the reaction showed turnover frequencies of
∼200 h–1 and high selectivity of 98:2 to
the desired linear aldehyde. The miniplant was operated continuously
for a total of 130 h. The control of the phase separation and catalyst
recycling for product isolation for a long time period appeared to
be challenging. Nevertheless, the separation was kept stable for over
24 h. The organic components in the product phase amounted to desired
values between 95 and 99 wt %. The desired 99.99% of the catalyst
remained in the aqueous catalyst phase.
BackgroundEven though a continuously high number of in vitro studies on nanoparticles are being published, the issue of correct dose matter is often not sufficiently taken into account. Due to their size, the diffusion of nanoparticles is slower, as compared to soluble chemicals, and they sediment slowly. Therefore, the administered dose of particles in in vitro experiments is not necessarily the same (effective) dose that comes into contact with the cellular system. This can lead to misinterpretations of experimental toxic effects and disturbs the meaningfulness of in vitro studies. In silico calculations of the effective nanoparticle dose can help circumventing this problem.ResultsThis study addresses more complex in vitro models like the human intestinal cell line Caco-2 or the human liver cell line HepaRG, which need to be differentiated over a few weeks to reach their full complexity. During the differentiation time the cells grow up the wall of the cell culture dishes and therefore a three-dimensional-based in silico model of the nanoparticle dose was developed to calculate the administered dose received by different cell populations at the bottom and the walls of the culture dish. Moreover, the model can perform calculations based on the hydrodynamic diameter which is measured by light scattering methods, or based on the diffusion coefficient measured by nanoparticle tracking analysis (NTA). This 3DSDD (3D-sedimentation-diffusion-dosimetry) model was experimentally verified against existing dosimetry models and was applied to differentiated Caco-2 cells incubated with silver nanoparticles.ConclusionsThe 3DSDD accounts for the 3D distribution of cells in in vitro cell culture dishes and is therefore suitable for differentiated cells. To encourage the use of dosimetry calculating software, our model can be downloaded from the supporting information.Electronic supplementary materialThe online version of this article (10.1186/s12989-018-0278-9) contains supplementary material, which is available to authorized users.
In many industrial applications impurities such as surfactants occur. These interfacially active molecules adsorb at liquid-liquid interfaces where they influence the occurring transport processes, which again affect reaction rates of multiphase reactions or contact times in extraction columns etc. To quantify the influences on the given applications, the interfacial coverage of the liquid-liquid interface with surfactant molecules must be known. The measurement of the fluid dynamics of single droplets provides a sensitive tool to capture any interfacial phenomena which changes the interfacial characteristics. This method was tested by applying two different surfactants in the system water/1-octanol. In some cases, the determination of the fluid dynamics provides a more reliable method for determining changes of the interfacial characteristics than the measurement of the interfacial tension.
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