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Panache
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we can salvage this thread, which is of a very interesting subject matter, if we stick only to the topic, methanol detection in alcoholic solutions
using wet chemistry techniques, ie not instrumentation.
i apologise for my rant regarding homeopathy, i meant not for it to be a broadstroke over every person you want to dicuss or believe or follows it. In
truth, i actually skim read, or didn't read the pot discussing homeopathy, only the ones on the methanol detection.
Back on topic then and can someone please get this if possible, thnx to entropy for finding it
http://pubs.acs.org/doi/abs/10.1021/ie50195a027
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weiming1998
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http://en.wikipedia.org/wiki/Copper(II)_sulfate
Just copy and paste that link because the link isn't working properly
Copper sulfate pentahydrate is soluble in methanol but both anhydrous and pentahydrate copper sulfate is insoluble in ethanol. Just get something like
5mls of alcoholic beverages, pour it in a watchglass, put anhydrous copper sulfate in, which would suck up the excess water and make copper sulfate
pentahydrate, which would dissolve in methanol. Now just light it.
[Edited on 30-1-2012 by weiming1998]
[Edited on 30-1-2012 by weiming1998]
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bahamuth
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Quote: Originally posted by weiming1998  | http://en.wikipedia.org/wiki/Copper(II)_sulfate
Just copy and paste that link because the link isn't working properly
Copper sulfate pentahydrate is soluble in methanol but both anhydrous and pentahydrate copper sulfate is insoluble in ethanol. Just get something like
5mls of alcoholic beverages, pour it in a watchglass, put anhydrous copper sulfate in, which would suck up the excess water and make copper sulfate
pentahydrate, which would dissolve in methanol. Now just light it.
[Edited on 30-1-2012 by weiming1998]
[Edited on 30-1-2012 by weiming1998] |
And lighting it would do what?
An example which would give you some grasp over the "wrongs" in your method.
Sucrose is soluble in 40% v/v EtOH/water, but virtually insoluble as the EtOH reaches 70% v/v. Why is that??
Let's say we have an anhydrous ethanol solution with 1% methanol in it, do you think the very few MeOH molecules bouncing around in that solution
would be able to solvate alot if any copper(II) ions? Highly doubt it.
As an addition, "insoluble" means IIRC less than 0.01M solute pr liter of solvent, so some Cu(II)SO4 would be soluble in the EtOH aswell (less than
~1.6g in this case)
Any sufficiently advanced technology is indistinguishable from magic.
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neptunium
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could we get back on the subject please ?
and stop with the name calling?
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Neil
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http://pubs.acs.org/doi/abs/10.1021/ie50195a027
Try the above, if you can find the full article.
The below is less usefull but interesting, it lists all of the data for Ethanol -depending on your water content you could just measure the liquids
density, BP, etc.
Attachment: Purification of solvents.pdf (446kB)
This file has been downloaded 872 times
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AJKOER
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| Quote: Originally posted by Panache | we can salvage this thread, which is of a very interesting subject matter, if we stick only to the topic, methanol detection in alcoholic solutions
using wet chemistry techniques, ie not instrumentation.
i apologise for my rant regarding homeopathy, i meant not for it to be a broadstroke over every person you want to dicuss or believe or follows it. In
truth, i actually skim read, or didn't read the pot discussing homeopathy, only the ones on the methanol detection.
Back on topic then and can someone please get this if possible, thnx to entropy for finding it
http://pubs.acs.org/doi/abs/10.1021/ie50195a027 |
Good paper and references.
I suspect for this and my Methyl bromide route, as we are working with tinctures, we should concentrate (distill taking the first few drops) to make
the test more powerful for the expected low dosage of Methanol.
I should have noted that my test observations of mortality (test subject ants, microbes,..) should have been recorded across a time variable. I like
my more complicated approach (albeit more dangerous) as having observed actual survival statistics, one is more confident that one is not looking at a
false positive (Methyl bromide stands out in its toxicity).
[Edited on 30-1-2012 by AJKOER]
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vmelkon
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There is something that I don't understand :
the solution that is being tested, does it contain a few percent of methanol or does it contain a few molecules?
From what I understand (documentary), homeopatic solutions are just water and some glucose. Also, I understand that they don't list the ingredients.
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AJKOER
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Per this source, the amount of Methanol can be 2% (a maximum tolerable concentration) varying, depending on source, to 5% (severe/fatal illness).
However, the numbers are the not the same for everyone varying due to ill health, malnutrition and personal factors (ethnicity, for example, and I
would guess deviation from normal in weight , age,.. , and uncertain if gender, after adjusting for weight, would be significant).
http://www.ncbi.nlm.nih.gov/pubmed/11926610
So for in the tinctures in question, the amount of methanol in question is probably low. Math: % alcohol x (2% to 5%).
[Edited on 30-1-2012 by AJKOER]
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weiming1998
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| Quote: Originally posted by bahamuth | | Quote: Originally posted by weiming1998 | http://en.wikipedia.org/wiki/Copper(II)_sulfate
Just copy and paste that link because the link isn't working properly
Copper sulfate pentahydrate is soluble in methanol but both anhydrous and pentahydrate copper sulfate is insoluble in ethanol. Just get something like
5mls of alcoholic beverages, pour it in a watchglass, put anhydrous copper sulfate in, which would suck up the excess water and make copper sulfate
pentahydrate, which would dissolve in methanol. Now just light it.
[Edited on 30-1-2012 by weiming1998]
[Edited on 30-1-2012 by weiming1998] |
And lighting it would do what?
An example which would give you some grasp over the "wrongs" in your method.
Sucrose is soluble in 40% v/v EtOH/water, but virtually insoluble as the EtOH reaches 70% v/v. Why is that??
Let's say we have an anhydrous ethanol solution with 1% methanol in it, do you think the very few MeOH molecules bouncing around in that solution
would be able to solvate alot if any copper(II) ions? Highly doubt it.
As an addition, "insoluble" means IIRC less than 0.01M solute pr liter of solvent, so some Cu(II)SO4 would be soluble in the EtOH aswell (less than
~1.6g in this case) |
But MeOH boils at a lower temperature (64 degrees celsius) than EtOH (78 degrees celsius), so if you distil it quite a few times, then dissolve in
copper sulfate. When you light it, it should give green flames.
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Neil
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If you are distilling it a few times and just throw away the first few portions to come over, all will be good anyways.
Edit: Thank you for letting the thread get back on topic Green.
[Edited on 31-1-2012 by Neil]
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rstar
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This topic has lengthened too much...
I think i'm going to try the anhydrous CuSO4 method that weiming said
thnx for the support 
"A tidy laboratory means a lazy chemist "
- Jöns Jacob Berzelius
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