Sciencemadness Discussion Board

Pressure in chemical bottles w/ temperature

thesmug - 27-2-2014 at 20:38

I recently got a huge shipment of chemicals, which includes many liquids. The bottles they come in don't have an enormous amount of air space so I'm a little concerned with the temperature of my storage room. It is around room temp., but always feels a little warm. I was wondering if this would be an issue with things like acetone, ethanol, etc... I don't really want a bottle of something to spontaneously explode :D!

confused - 27-2-2014 at 22:46

i had that happen while trying to synthesize trichloromethane once, failed to take into consideration the vapour pressure of it, the container exploded. :D
but i live in thr tropics, where the temperature is a constant 30'C

but never had that happen when storing chemicals indoors or in the lab where the temperature is about 25'c

if you're very concerned about the buildup of pressure, you might want to open the caps of the bottle to vent the pressure every now and then.

thesmug - 27-2-2014 at 23:23

Quote: Originally posted by confused  
i had that happen while trying to synthesize trichloromethane once, failed to take into consideration the vapour pressure of it, the container exploded. :D
but i live in thr tropics, where the temperature is a constant 30'C

but never had that happen when storing chemicals indoors or in the lab where the temperature is about 25'c

if you're very concerned about the buildup of pressure, you might want to open the caps of the bottle to vent the pressure every now and then.

That's what I thought of doing.

MrHomeScientist - 28-2-2014 at 09:07

If you're concerned, buy a small lab fridge. That's what I did for things with high vapor pressure like dichloromethane, and a little fridge is cheap. I use that more to cut down on vapors leaking through the caps. I'm not concerned at all about bottles exploding due to minor temperature changes in my house.

testimento - 28-2-2014 at 13:44

The thick glass industrial bottles hold against pressure quite well, and their bursting pressures could be even as high as 10-20 bars, so in ordinary temperatures, between 0-40C there would be no major risk, except those of special note like ethers and very low boiling liquids which should be stored in fridge. I have seen ether being sold in large aluminium containers which are neatly shaped so they would probably easily hold those pressures before rupturing.

Oscilllator - 28-2-2014 at 17:02

You really only need to refrigerate about solvents with a b.p. near room temperature (diethyl ether, dichloromethane, pentanes etc). Those are the only ones that have any chance at all of exploding at room temperature. Also, releasing the cap to release pressure is pointless in this situation, since the pressure will build up to where it was before in a matter of minutes. The only time you need to open the cap to release pressure is with chemicals that decompose, like H2O2.

thesmug - 28-2-2014 at 18:35

Quote: Originally posted by Oscilllator  
You really only need to refrigerate about solvents with a b.p. near room temperature (diethyl ether, dichloromethane, pentanes etc). Those are the only ones that have any chance at all of exploding at room temperature. Also, releasing the cap to release pressure is pointless in this situation, since the pressure will build up to where it was before in a matter of minutes. The only time you need to open the cap to release pressure is with chemicals that decompose, like H2O2.

How often do you vent your H2O2?

Mailinmypocket - 1-3-2014 at 04:34

Do you refrigerate your peroxide? I have seen it sold in these accordion shaped bottles that expand(I've only seen this with Flinn Scientific, the most safety paranoid company I've ever seen). The 35% peroxide I get is food grade (no stabilizers added) and the bottles are in the fridge... Even the brand new one that I haven't opened since I bought it over a year ago made no "pssssssht" when I opened it just now.

[Edited on 1-3-2014 by Mailinmypocket]

Oscilllator - 1-3-2014 at 19:46

Quote: Originally posted by thesmug  
Quote: Originally posted by Oscilllator  
You really only need to refrigerate about solvents with a b.p. near room temperature (diethyl ether, dichloromethane, pentanes etc). Those are the only ones that have any chance at all of exploding at room temperature. Also, releasing the cap to release pressure is pointless in this situation, since the pressure will build up to where it was before in a matter of minutes. The only time you need to open the cap to release pressure is with chemicals that decompose, like H2O2.

How often do you vent your H2O2?

Never. I'm not sure, but I think it has a cap that releases pressure, which is why H2O2 leaked out in the postage :(. At any rate, I have never noticed a release of pressure when I open the bottle.

@Mailinmypocket I dont refrigerate my peroxide but this is only because I don't have a lab fridge.