A Benzene Ring
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Is there a cheap way to pump acetonitrile for use in a continuous flow reactor?
Hi,
I have been trying to find a way to pump around acetonitrile for photochemical reactions with a continuous flow reactor, and I am stuck on finding a
material for the tube in the pump head itself. I originally tried PFA, but it just made the peristaltic pump seize up since the PFA was likely way too
stiff. I could try PTFE or FEP, but I feel like they would provide the same results as they have very similar physical properties, and other
specialized polymers are out of my budget.
Does anyone have any ideas on how I could do this? Maybe another plastic or pump type could be used. Cost is a big factor in this project, and I would
need a solution to be relatively cheap.
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Sulaiman
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Does anyone have any ideas on how I could do this?
Something other than methyl cyanide maybe ?
Honestly, I hope that you fail
- because: you chose poorly... too toxic (accidents WILL happen)
(if it is economically viable it may become widely used)
................................
I can't think of a suitable material for a peristaltic pump at the moment, but:
assuming that you are at an early stage of prototyping you could just use gravity,
each side of the cell having two reservoirs,
raising one reservoir level above its paired unit will cause liquid to flow.
you could even make a see-saw or similar (eg equal arm balance-like)
for multiple cycles.
An air tube between the tops of pairs would allow pressure equalisation without venting.
Ultimately I guess that you would need something like:
a ptfe diaphragm pump for medium flow rates
or a chemically resistant centrifugal pump for high flow rates.
Edit: IDEA: Two reservoirs per side, connected at their bottoms via one side of the cell,
it can be fixed, level, and use rigid connections.
liquid can be pumped from one reservoir to its paired container by air pressure.
If no membrane between liquid and air, the pump will be exposed to vapour if a closed system is adopted,
or, you could use only positive pressure accepting that vapours will be vented each cycle.
[Edited on 7-3-2026 by Sulaiman]
CAUTION : Hobby Chemist, not Professional or even Amateur
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Texium
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Quote: Originally posted by Sulaiman  | Something other than methyl cyanide maybe ?
Honestly, I hope that you fail
- because: you chose poorly... too toxic (accidents WILL happen)
(if it is economically viable it may become widely used)
................................ |
What are you talking about? Acetonitrile (regardless of whether you prefer
to call it "methyl cyanide" to make it sound scarier) has an oral LD50 of over 2 grams/kg... this puts it in the same neighborhood of toxicity as
solvents I'm sure you'd have no issue with using, such as acetone and methanol. Its metabolism is much slower than other nitriles, allowing for
detoxification and excretion to happen faster than cyanide can build up, which makes it surprisingly safe to handle.
----------------
Anyway... unfortunately I don't have a great suggestion for a tubing material. HPLC/MS systems I have used with acetonitrile typically use PEEK
tubing, but although it is non-fluorinated, it is also quite stiff and likely not flexible enough for a peristaltic pump. You probably need to
consider other pump types. Perhaps study the workings of a flash chromatography system, such as this: https://medproequipment.com/wp-content/uploads/2024/02/Biota... The pressure/throughput/solvent compatibility demands should be similar to what
you need.
That manual doesn't elaborate on exactly what kind of pump is used, but it sounds like it's some kind of piston pump. You may even be able to find an
older flash LC system for parts that you could get relatively cheap and salvage useful components from.
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Texium
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Thread Moved
7-3-2026 at 11:24 |
Sulaiman
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my bad .. sorry
I did deliberately use "methyl cyanide" for dramatic effect
because I genuinely thought that it is too toxic for widespread use,
so I wanted to emphasise that.
If you say it is safe then I withdraw that criticism,
and hope that the project succeeds.
CAUTION : Hobby Chemist, not Professional or even Amateur
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A Benzene Ring
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I will look into other tubing types and PEEK tubing, but it is unlikely they will be suitable for this project.
If I can’t use a peristaltic pump, then I might just have to diy a different kind of pump,
maybe I can diy something like a syringe pump with glass syringes and PFA tubing.
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charley1957
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https://theelectronicgoldmine.com/cdn/shop/files/G29486-8_90... This pump is advertised to be made of chemical-resistant thermoplastic, resistant
to aggressive chemicals, caustics, acids, chilled fluids, etc. It is magnetically coupled, so it can’t be run dry. I’ve got one I used for
transferring sulfuric acid. Worked fine for that. Right now they have it for $99 plus shipping. I haven’t checked the price anywhere else.
It’s not on Amazon, but it is also sold by a company called Xylem, where you can find more information.
[Edited on Mar03-8-2026 by charley1957]
You can’t claim you drank all day if you didn’t start early in the morning.
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BromicAcid
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There is a masterflex system that utilizes a PTFE pump head. It's the go-to at my work to meter in pretty much any chemical out there. They last
quite a while in use, hundreds of hours if not too much back pressure or you didn't accidentally crank down the tension too much. That being said the
whole masterflex system costs an arm and a leg. The pump head tubing isn't too bad, but the drive is several thousand dollars.
Supposedly though polypropylene has good to excellent chemical resistance to ACN depending on the source. Seems like that would be a good choice
since I've seen a lot of pump heads, especially the drop and load style that can use that as a material for a pump head.
Attachment: GY_0692.pdf (343kB)
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