Thread by @DrLutzBoehm

I mostly showed you #bubbles rising in aqueous systems. Not so often discussed, also in literature, are bubbles rising in organic phases.
Here's an Argon bubble rising in dichloromethane (DCM).
What is the difference?
#fluiddynamics #chemicalEngineering
A 🧵1/8
#SciComm #WissKomm

Other liquids have different material properties. The density of DCM is larger in comparison to that of water by more than 30%. The viscosity is less than half than that of water, and the surface tension is about 1/3 compared to water.
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All of this leads to another rising behavior, rise velocity, shape of the bubbles, rising path, and so on.
In literature, organic phases are less discussed as using these usually leads to much stronger safety precautions.
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Depending on what you use, this stuff can be nasty, cause cancer and be harmful to your fetus, and so on. But you wouldn't drink it anyway, right? The problem is that organic phases usually have a low vapor pressure.
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You definitely need a fume to avoid the accumulation of the vapor in the lab atmosphere.
We used this system as our colleagues @HerresLab from @RWTH worked on a reactive copper complex system based in DMC with the ligand DBED.
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We inserted oxygen bubbles, and there was a mass transfer of oxygen from the gas to the liquid (absorption), in the liquid this oxygen reacted.
Our method to determine mass transfer is based on the optical method to analyze bubble shrinkage.

https://twitter.com/DrLutzBoehm/status/1513446909280768004?s=20&t=P_D4zyTGBGim8ym0SRWP2Q

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Remember what I said about the vapor pressure earlier? Big problem! The bubble size almost does not change although oxygen is transferred to the liquid. But also DCM evaporates at the bubble interface and the vapor is accumulating in the bubble. This almost counterbalances
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You need other methods to analyze the mass transfer here, e.g., you can collect the bubble at the top of the column and apply gas chromatography to determine the components and their concentrations in the #bubble.

Thanks for reading. Questions? Comments?
#SciComm #WissKomm 8/8