Flame test of alcohols

Yummyrum

I was setting up some spirit lamps at work today and I thought I'd take some pics as recently there was a mention of checking for methanol by the colour of burning it .
I had to set up 4 x lamps  with Methanol , Ethanol , Butan-1ol  or 1-Butanol  and propan-1ol or 1-Propanol .

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Here's a close up of each .

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Then I thought , OK does it look the same if you burn them on a spoon .So I set a few drops in a well plate .
The results are completely different to the spirit lamp test .The Very yellow looking Methanol flame on the burner is a very blue flame with no sign of yellow at all . If you look at the tip of the Ethanol flame you can see a slight yellow tinge .

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And remember that these are pure alcohols . I don't recon anyone could guess what was in their spoon off the still  

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My recommended goto .
https://homedistiller.org/wiki/index.ph ... ion_Theory

Saltbush-Bill

Nice work Yummy  

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What has been used to fuel those lamps before hand?
The wicks could have residue from previous fuels.

Birrofilo

Also, when burning a substance with a wick, also the wick is burning I suppose, even though slowly.

Yummyrum

They are the same year after year Salty ...for that reason ....no cross contamination .I think this has a lot to do with it . But it sure is interesting how the Methanol can go from a yellow with a wick to a blue on its own .My recommended goto .
https://homedistiller.org/wiki/index.ph ... ion_Theory

seamusm53

This is an interesting video and discussion.
https://www.reddit.com/r/chemicalreacti ... nol_right/
My take from all this - don't trust your life to be able to tell the difference based on a flame test when adulteration is usually a deliberately poisoned mix of ethanol and methanol not pure methanol.  I know what comes from my own handiwork and at least here at home feel reasonably safe drinking commercial spirits.  But otherwise........

Alchemist75

The only thing i've ever been able to deduce using the "flame test" on product taken off the still was a rough gauge of proof. A tall blue flame with a pronounced gold cap that leaves the spoon dry is gonna be 85%+, the more tall and pronounced, the higher proof. A lower blue flame with little to no gold cap leaving water behind is below 75-80%. Approximate test at best and no indication of contamination unless it's really burning an off color.SOLVE ET COAGULA, ET HABEBIS MAGISTERIUM

cayars

The color or lack of color will depend on what you run as well.
There really isn't much useful information to get from a flame test.  It can be pretty easy to not even see a flame at times. Setting alcohol on fire probably isn't the smartest move we can do even if done over a sink.
I've got a big utility sink in my basement. Goofing around I dumped foreshots in the sink.  Did a flame test on a spoon and dumped that into the sink.  You know what happened next, the foreshots that didn't go down the drain caught fire just like I thought they would.  Flame tests are an accident waiting to happen.Programmer specializing in process control for ExxonMobil (ethanol refinery control), WT, Omron, Bosch, Honeywell & Boeing.
More than a decade working for NASA & FAA Tech with computer code used on Space Shuttles and some airline flight recorders.

shadylane

Don't forget the air temp
It can be difficult to get even high proof to light on a cold day.
On a hot day, you'll know it's lit when the hairs on your hand start curling up  

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Saltbush-Bill

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Hell  how cold does it get there......that problem doesnt exist in my neck of the woods.

Alchemist75

Yep, if it's hot enough even 25% will ignite. Shoot, on a frigid cold day like yesterday even my lighter has trouble striking.SOLVE ET COAGULA, ET HABEBIS MAGISTERIUM

shadylane

100% alcohol has a flash point of around 13'c
For the forum members from the  scientifically challenged part of the world
That equals 50 something degrees Fahrenheit

Chauncey

10c is 50f so a little higher
When people tell me I'll regret that in the morning,  I sleep till noon.

Bradster68

This is some over the top stuff right here.
Very cool project/experiment.