Fantasma4500
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Registered: 12-12-2012
Location: Dysrope (aka europe)
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Getting rid of Sulfur Trioxide
Hello, i recently had an idea of making 98% H2SO4, without a fuming hood, now before you yell at me to get a fume hood or stop before i kill myself,
the trick in this.. The trick in this is.. to get rid of the sulfur trioxide, instead of having it everywhere, as its toxic and also one of the worst
gasses (at least the ones ive tried to smell)
What i had in my mind of getting rid of the sulfur trioxide was:
a heatresistant vacuum filter bottle, top stoppered off with glass, fitted with wettened cotton wool
and a tube on the side made of PTFE
So today i thought, i have a small amount of concentrated H2SO4 contaminated with LiSO4, then i could get LiSO4 and see if this whole thing with
getting rid of the SO3 would work
now again.. before you go on saying that its irresponsible and i could kill myself.. i had gloves and glasses on when the SO3 was forming, also the
amounts was less than 5 mL of sulfuric acid
So i put up my vacuum flask, fitted my PTFE hose on, lead it into a 0.5 litre plastic bottle with 37% H2SO4, poured in the LiSO4/H2SO4 and turned on
the heat
first water was going into the bottle with H2SO4, then SO3 started to form and i quickly got ready for anything that should occur, about 30 seconds
after i put gloves on and glasses i heard a loud splitering crack.
My vacuum flask was broken, now it was more just a glass cone and a bottom with hot H2SO4 on
SO3 was everywhere, and i put the bottom of the vacuum flask in my sink and while i took the top in my sink it started departing into 3 pieces
(probably due to heat difference) and i got rid of the H2SO4 that got onto my heat stove.
Nothing more happened, no injuries at all, but i lost a vacuum flask.
I was informed by the seller, or more confirmed by the seller, that this was standard lab glass (metaborosilicate) and it was heat resistant.. if SO3
cant be handled in glass.. what can it be handled in??
i have some ideas on what might of happened tho.
Oleum could have formed, as the condensed water reacted with the SO3 in the air, dripping down on the bottom, going into 2 parts H2SO4, splitting the
glass
http://imgur.com/1AXae
Pressure might of been too high, but i dont understand if this should be why, because the hose lead into a bottle, which wasnt closed, with just about
50-100 mL H2SO4
Im sharing this to perhaps get some ideas on how to get rid of SO3, and also so that people might think twice when attempting to handle SO3 in
glassware (;
[Edited on 29-12-2012 by Antiswat]
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Lambda-Eyde
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Sulfur trioxide isn't reactive towards glass. What you did wrong was to heat a thick-walled filter flask. They are NOT meant to be heated, the thick
glass expands differently and cracks it, unless it's made from quartz.
This just in: 95,5 % of the world population lives outside the USA
You should really listen to ABBAPlease drop by our IRC channel: #sciencemadness @ irc.efnet.org
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hissingnoise
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I would have thought that even H2SO4-wetted lithium sulphate would have a very high decomposition temperature?
Perhaps what you saw was small quantities of SO3 evolved from boiling H2SO4?
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Fantasma4500
International Hazard
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Quote: Originally posted by Lambda-Eyde  | | Sulfur trioxide isn't reactive towards glass. What you did wrong was to heat a thick-walled filter flask. They are NOT meant to be heated, the thick
glass expands differently and cracks it, unless it's made from quartz. |
oh, i guess that kind of explains this whole mess, the seller told me that it was metaborosilicate glass, so i didnt see any harm in heating it abit
afterwards i heated it up with butane burner just for fun, and dipped it in a few drops of water in my sink where it quickly cracked in the bottom,
very fine cracks, and over time slowly cracked a larger chunk off..
i guess i would need some SO3 resistant stopper, or something SO3 resistant i could wrap around my PTFE hose and put ontop of an erlenmeyer flask
another time then..
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Fantasma4500
International Hazard
Posts: 1681
Registered: 12-12-2012
Location: Dysrope (aka europe)
Member Is Offline
Mood: dangerously practical
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| Quote: Originally posted by hissingnoise | I would have thought that even H2SO4-wetted lithium sulphate would have a very high decomposition temperature?
Perhaps what you saw was small quantities of SO3 evolved from boiling H2SO4?
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oh yes, i wasnt planning on decomposing the lithium sulfate at first, it was just to remove the SO3 coming from the decomposing H2SO4 so i could get
lithium sulfate for use in making lithium chlorate and permanganate..
my setup is entirely, or WAS entirely for REMOVING the SO3 and perhaps finding use in the process (further concentrating of 37% H2SO4)
and making 98% H2SO4 when i would take it as a reliable procedure..
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