Sciencemadness Discussion Board

Liquefying SO2 into a Plastic Bottle

Parakeet - 30-6-2023 at 04:40

According to this graph, the boiling point of SO2 at 4-5 atm is about 30℃. [Source]
SO2 vapor pressure.png - 7kB

And since 830 kPa of pressure is exerted on normal carbonated water bottle, I thought these carbonated water bottles can safely keep liquefied SO2 at room temperature, at least in theory.

Could this be an effective cylinder for SO2, or would it be as stupid as it sounds?


Lionel Spanner - 30-6-2023 at 06:21

It's very likely to dissolve or severely corrode the plastic, especially under pressure.

Also, how would you open it without it vaporising and going everywhere?

teodor - 30-6-2023 at 06:27

If you can it would be great savings of money, because I paid 40 EUR + for 10 atm glass bottle.

Sir_Gawain - 30-6-2023 at 11:38

Quote: Originally posted by teodor  
If you can it would be great savings of money, because I paid 40 EUR + for 10 atm glass bottle.

Yes, but I would rather pay 40 EUR than have a bottle of liquid SO2 explode in my face.

clearly_not_atara - 30-6-2023 at 21:20

Quote: Originally posted by teodor  
If you can it would be great savings of money, because I paid 40 EUR + for 10 atm glass bottle.

Is stainless steel not compatible with liquid SO2?

teodor - 1-7-2023 at 02:53

Quote: Originally posted by clearly_not_atara  
Quote: Originally posted by teodor  
If you can it would be great savings of money, because I paid 40 EUR + for 10 atm glass bottle.

Is stainless steel not compatible with liquid SO2?


I have only one high pressure bottle from stainless steel and have no idea where to buy more, so I don't know the price of it.

Sulaiman - 1-7-2023 at 05:06

I've no expertise with liquid SO2 storage,
but I can imagine several problems;
eg flash-boiling if pressure released at RT. (valve required)
or brittle plastic if stored in a freezer (bp=-10oC @ 1atm)

I suspect that a plastic bottle will work fine :)
- until it doesn't :(

I would rather generate SO2 on demand than store liquid SO2

Sir_Gawain - 1-7-2023 at 08:56

Why would you even want to store SO2? To get around the EU sulfuric acid ban?

[Edited on 1-7-2023 by Sir_Gawain]

Parakeet - 1-7-2023 at 21:37

Quote: Originally posted by Lionel Spanner  
It's very likely to dissolve or severely corrode the plastic, especially under pressure.

That might be a problem. I couldn’t find the chemical resistance data of PET against liquid sulfur dioxide. Does anyone have it?
Or I think I should test it by dipping a small piece of PET in liquid SO2, but then I need a pressure resistant container to prepare it…


@Sulaiman, @Sir_Gawain
Yeah, you are actually right. But I still think cylinders are slightly easier to use when you want to use SO2 in reactions : you won't need another flasks and dropping funnel to generate it.

Parakeet - 1-7-2023 at 21:38

Quote: Originally posted by teodor  
If you can it would be great savings of money, because I paid 40 EUR + for 10 atm glass bottle.

Oh, and what apparatus did you buy, specifically? Do you have any pictures or a link to the manufacture?

Lionel Spanner - 2-7-2023 at 08:09

Quote: Originally posted by Parakeet  
Quote: Originally posted by Lionel Spanner  
It's very likely to dissolve or severely corrode the plastic, especially under pressure.

That might be a problem. I couldn’t find the chemical resistance data of PET against liquid sulfur dioxide. Does anyone have it?

PET gets knackered by a water/acetone mixture. It's got no chance whatsoever standing up to liquid sulphur dioxide.

Sulaiman - 2-7-2023 at 09:04

Polypropylene (nalgene) looks to be compatible with SO2


Attachment: Graco_ChemCompGuideEN-B.pdf (687kB)
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Parakeet - 3-7-2023 at 00:25

Quote: Originally posted by Sulaiman  
Polypropylene (nalgene) looks to be compatible with SO2

Interesting! Nice reference.
Unfortunately though, PP becomes weak in cold places, iirc.

teodor - 3-7-2023 at 00:54

Quote: Originally posted by Parakeet  
Quote: Originally posted by teodor  
If you can it would be great savings of money, because I paid 40 EUR + for 10 atm glass bottle.

Oh, and what apparatus did you buy, specifically? Do you have any pictures or a link to the manufacture?


Parakeet, just do search "proglass pressure vessel", you will find the info. The only one thing I don't like is a rubber o-ring which limits the number of gases which could be stored. I think for some application it should be replaced with o-ring made of PTFE, but this should be bought separately.

Update: I've checked the description and it seams the o-ring in my bottle is from FKM. But I would say it looks like ordinary rubber.

[Edited on 3-7-2023 by teodor]

Tsjerk - 3-7-2023 at 01:55

A quick Google search learned me stainless steel is OK for dry SO2:

ThyLabs has a video using CO2 paintball canisters:
https://www.youtube.com/watch?v=Q70Q5PCxn0c&ab_channel=T...