kaviaari
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Dangers of methanol vapours
Yesterday I made DMO from oxalic acid and methanol. During recrystallation I had to use hot methanol (about 50ml) and I was quite concerned about the
methanol vapours in non-ventilated laboratory. I capped the flasks containing hot methanol with cotton plugs and after working I opened the doors and
ventilated the room. Is this enought or should I go outdoors when handling hot methanol?
[Edited on 1-3-2007 by kaviaari]
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Furch
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I strongly doubt that the amount of vapours from your standard small scale recrystallization are in lethal amounts. That doesn't mean it's healthy,
though.
I read somewhere that an appreciated lethal dose of methanol is somewhere in the 50 ml range, i.e. 40+ g or so, for an adult.
Either way I still recommend you do this outdoors, as you suggested, or with lots of open windows/doors etc. If this isn't possible, then at least try
and condense the methanol vapours somehow.
\"Those who say do not know, those who know do not say.\" -Lao Tzu
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Sauron
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If you value your optic nerves, go ahead and ventilate all you like, or work outdoors. Goggles, gloves, and a respirator are good ideas.
Lots and lots that one should not do without a hood. Methanol isn't the worst but it is not benign.
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Magpie
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I used to rent various sailboats in the 30 foot length range for about 1 week at a time each summer. Many of them had alcohol cooking stoves, which
of course were located down in the small enclosed cabin. I'm sure I smelled alcohol vapors often, especially when attempting to light them on a cold
morning. I don't remember any special warnings, or do I think that I (or my family) suffered any from this.
I'm not saying to be careless with methanol, but no need to over react either, IMHO.
The single most important condition for a successful synthesis is good mixing - Nicodem
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unionised
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Alcohol isn't always methanol. What were you cooking with Magpie?
Anyway, methanol is toxic but you seem to have got away with it.
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Magpie
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Unionized you have a point. I always just assumed it was methanol based on its smell. I'll do a little looking and see what kind of alcohol these
boat stoves normally use(d). In the later years most of the boats had compressed natural gas, IIRC.
The single most important condition for a successful synthesis is good mixing - Nicodem
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kaviaari
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| Quote: | Originally posted by Magpie
Unionized you have a point. I always just assumed it was methanol based on its smell. I'll do a little looking and see what kind of alcohol these
boat stoves normally use(d). In the later years most of the boats had compressed natural gas, IIRC. |
.. interesting, I thought that methanol doens't have a very strong smell of it's own? Just faint odour of ethanol.
[Edited on 1-3-2007 by kaviaari]
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Magpie
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I tried to find the compostion of marine stove alcohol but could find no definitve answer. Mostly it is "denatured alcohol." One would think that
this is mostly ethanol. But not always. Some can be mostly methanol!
Recochem, a Canadian company, sells a marine stove alcohol that they say is methanol.
The single most important condition for a successful synthesis is good mixing - Nicodem
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Sauron
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Sterno (for portable stoves) is thickened methanol.
I don't think methanol smells much like ethanol at all. I wouldn't really recommend spending too much time comparing them, either.
I used to keep a vat of saturated KOH in methanol for cleaning glassware. I kept it outside and next to a vat of rinse water (with an overflow so the
water was changed) and a vat of faintly acidified water to remove any alkili traces that got carried over. This was my routine glassware cleanup. Once
in a while it would cause trouble because it was well nigh impossible to get all the traces of KOH out of ground glass surfaces and these could affect
a sensitive reaction. In those cases there was no choice but to use "virgin" glassware and segregate it for cleaning with Alconox detergent only and
dedicate it for such reactions.
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