Droso
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Metaldehyde isolation and purification?
Anybody here know how one could isolate metaldehyde from slug, snail pesticide? Its seems like an interesting compound that I wish to have in pure
form.
The only problem is that there seems not much information about the concentration used on the poison nor the properties of this compound (solubilty,
etc).
Thanks
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Etaoin Shrdlu
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Look up the SDS for the brand you have. It looks as though the compound is usually present in fairly low amounts. (<5%)
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nux vomica
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Wiki says that it sublimes between 110-120°c heating in a sealed container might work if you can keep between these temperatures.
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Texium
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Thread Moved
22-12-2015 at 07:44 |
nux vomica
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Thought I would try sublime some 15 grm per kg metaldehyde snail pellets I heated 60 grms at 180°c for one hour , got .55 of a gram of nice hair like
metaldehyde crystals not the .9 grms in theory , still it seems to work.
Nux.
[Edited on 23-12-2015 by nux vomica]
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UC235
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I'm frankly impressed that such a simple method works so well.
Now the bigger question: is metaldehyde as aggravating a source of acetaldehyde as 1,3,5-trioxane is a source of formaldehyde?
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nux vomica
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I've been trying to get my head around the molar mass differences between acetaldehyde and metaldehyde.
If acetaldehyde is 44.05 grams per mole is 176.212 grams of metaldehyde (1mole) the equivalent amount to use in the place of liquid acetaldehyde in a
synthesis.
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DJF90
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Seeing how metaldehyde is just a tetramer of acetaldehyde, you'd use the same amount on a mass basis (e.g. 1 g acetaldehyde is equivalent to 1 g
metaldehyde).
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nux vomica
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Quote: Originally posted by DJF90  | | Seeing how metaldehyde is just a tetramer of acetaldehyde, you'd use the same amount on a mass basis (e.g. 1 g acetaldehyde is equivalent to 1 g
metaldehyde). |
Thanks for that DJF90 I thought that might be the case.
What threw me was formaldehyde and paraformeldyhyde molar weights are only slighty different and they are one for one equivalents , the large
difference between acetaldehyde and metadehyde made me think you needed more metadehyde to make a equivalent amount of acetaldehyde..
Thanks nux
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DJF90
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The difference with paraformaldehyde is that it is a polymer of undefined length, and so the molecular weight given for this material tends to be the
same as that for formaldehyde.
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careysub
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| Quote: Originally posted by nux vomica | Thought I would try sublime some 15 grm per kg metaldehyde snail pellets I heated 60 grms at 180°c for one hour , got .55 of a gram of nice hair like
metaldehyde crystals not the .9 grms in theory , still it seems to work.
Nux.
[Edited on 23-12-2015 by nux vomica] |
Thanks for this. As it happens I just received some 10% metaldehyde slug bait, and was debating how to extract it. Perfect timing!
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Magpie
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| Quote: Originally posted by DJF90 | | The difference with paraformaldehyde is that it is a polymer of undefined length, and so the molecular weight given for this material tends to be the
same as that for formaldehyde. |
IIRC paraformaldehyde polymer chains are terminated with a water molecule. This would account for a slight difference in the MW of the monomer vs
that of formaldehyde.
[Edited on 23-12-2015 by Magpie]
The single most important condition for a successful synthesis is good mixing - Nicodem
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nux vomica
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Did another 60 gram run got 0.53 grams of metaldehyde theoretical .9 grams there was a amount of crystals that recombined with the top of the pellets
though so I could get a better return. Nux
 
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Magpie
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Nice work, nux.
It would be interesting to see what yield of acetaldehyde can now be achieved. However, for a synthesis it might be more efficient to use the
metaldehyde "as is."
[Edited on 24-12-2015 by Magpie]
The single most important condition for a successful synthesis is good mixing - Nicodem
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nux vomica
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| Quote: Originally posted by Magpie | Nice work, nux.
It would be interesting to see what yield of acetaldehyde can now be achieved. However, for a synthesis it might be more efficient to use the
metaldehyde "as is."
[Edited on 24-12-2015 by Magpie] |
Thanks magpie I would like to try to and make some Pentaerythritol but the alkaline conditions probably won't work with the metaldehyde.
It would have to be acidic to release the acetaldehyde if I am correct .
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