countrychemist
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ethylene glycol and sulfuric acid?
I have a question on a take home toxicology test that reads like this: In a recent news story, an individual
accidentally added antifreeze to a battery (a big battery in an electric forklift). This resulted in toxic fumes. A couple of workers were affected
but there were no deaths. Speculate on what the toxic fumes may have been.
I know that the oxidation of ethylene glycol can lead to formaldehyde gas, but what else could there be coming from this?? Thanks.
P.S. just stumbled onto this forum...looks pretty cool, I'm sure I'll be frequenting the site now!
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Mephisto
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Sounds like the formation of dioxane. But for toxic fumes the components had to be hotter than room temperature.
~Mephisto
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praseodym
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Dioxane being formed from reaction of ethylene glycol and sulphuric acid? Can someone tell me how does it work?
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Mephisto
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The mechanism is shown in the German Wikipedia. Just ignore the first line in the picture. The condensation of two ethylene glycol molecules and the
following cyclization are both acid-catalyst SN2-reactions.
~Mephisto
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Mephisto
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BTW: In the past I wanted to write down a nice text how to synthesize and purify 1,4-dioxane, but I had never the time for it. However, during my
research I've scanned the main monograph about dioxane. It's in German language, but tells almost everything about dioxane. How to prepare
radioactive marked 1,4-dioxane, how to chlorinate dioxanes, etc...
If someone is interested, here is the link.
Stumpf, Walter - Chemie und Anwendung des 1,4-Dioxans.pdf
~Mephisto
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praseodym
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OK...thanks...luckily it's in german, I wouldn't understand a thing if it is in other foreign languages.
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Fantasma4500
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sorry for reviving old thread, but i'd like to give my short input regarding EG and H2SO4..
i attempted to create triethyl borate through EG H2SO4 and H3BO3 in not weighting anything out, it was done on 10mL scale
a small flask was subjected to heating and it eventually turned darkyellowish, a painful gas was present within the flask after it reached decently
high temperature
i mean to call it that dioxane is what gives most of the odor from a fire within a building, and if im not wrong is somewhat relative to the smell of
phenol, i did not note this smell, but rather a painful smell coming very close to the gasous pain from formaldehyde
i have not scaled up this reaction yet but i'd say there are good chances of formaldehyde to be produced from H2SO4 and EG combined thereafter heated,
i guess if the gas would be lead into or together with acetaldehyde hexamine could be formed and be left behind after the excessive acetaldehyde would
be evaporated off could point further towards the existence of formaldehyde from this reaction, i may be lazy for not having looked into other ways of
testing for, prove or disprove formaldehydes presence
i used about 1mL H2SO4 and 10 mL seemingly anhydrous mono-ethyl glycol, flask was capped off with aluminium foil, not sure if the EG managed to boil
even, so it may have been taking place even without reaching EG's boiling point
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UC235
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Quote: Originally posted by Antiswat  | sorry for reviving old thread, but i'd like to give my short input regarding EG and H2SO4..
i attempted to create triethyl borate through EG H2SO4 and H3BO3 in not weighting anything out, it was done on 10mL scale
a small flask was subjected to heating and it eventually turned darkyellowish, a painful gas was present within the flask after it reached decently
high temperature
i mean to call it that dioxane is what gives most of the odor from a fire within a building, and if im not wrong is somewhat relative to the smell of
phenol, i did not note this smell, but rather a painful smell coming very close to the gasous pain from formaldehyde
i have not scaled up this reaction yet but i'd say there are good chances of formaldehyde to be produced from H2SO4 and EG combined thereafter heated,
i guess if the gas would be lead into or together with acetaldehyde hexamine could be formed and be left behind after the excessive acetaldehyde would
be evaporated off could point further towards the existence of formaldehyde from this reaction, i may be lazy for not having looked into other ways of
testing for, prove or disprove formaldehydes presence
i used about 1mL H2SO4 and 10 mL seemingly anhydrous mono-ethyl glycol, flask was capped off with aluminium foil, not sure if the EG managed to boil
even, so it may have been taking place even without reaching EG's boiling point |
Why on earth did you think that ethylene glycol would magically reduce itself to an ethyl group? Ethylene glycol can rearrange under acid catalysis to
acetaldehyde, which is almost definitely what you experienced.
I have done a prep of 1,4-dioxane from ethylene glycol and sulfuric acid. The mixture is simply distilled and produces a small amount of tarry
polymerization products and a stillpot containing 1,4-dioxane, water, 2-methyl-1,3-dioxolane (acetaldehyde ethylene glycol acetal), and small amounts
of free acetaldehyde and SO2. NaOH added to this causes immediate color change from the presence of the aldehyde. After a second treatment and
distillation, you're down to dioxane and the dioxolane.
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Fantasma4500
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well i confused ethylene with ethyl
but i dont quite understand it.. wikipedia suggests 1,4-dioxane is mild ether odor, but that is def not what i have in a flask by now... wouldnt it be
too far out to imagine boric acid having catalysed this reaction into forming formaldehyde instead of dioxane?
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