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Author: Subject: Tar from H2SO4 + sugar reaction?!
Draeger
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[*] posted on 22-8-2020 at 06:53
Tar from H2SO4 + sugar reaction?!


I did the reaction by just mixing sugar and H2SO4 in a graphite crucible. A snake formed as thought. I let it cool over a night. Next day, I pull it out, and the bottom part of it is covered by a strange, very sticky tar. Trying to wash it off reveals that the bottom part of the snake is very thickly covered or maybe even made of it.

What is this tar? What do I do with it?




Collected elements:
Al, Cu, Ga, C (coal), S, Zn, Na

Collected compounds:

Inorganic:
NaOH; NaHCO3; MnCl2; MnCO3; CuSO4; FeSO4; aq. 30-33% HCl; aq. NaClO; aq. 9,5% ammonia; aq. 94-96% H2SO4; aq. 3% H2O2

Organic:
citric acid, sodium acetate, sodium citrate, petroleum, mineral oil
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Junk_Enginerd
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[*] posted on 22-8-2020 at 08:10


Isn't it likely just syrup made of not entirely reacted sugar, carbon, water and h2so4? I don't think you can get actual tar out of sugar.

Edit: I see now this was after leaving it overnight, meaning it has probably absorbed lots of moisture from ambient air, probably making syrup. Very unappetizing syrup.

[Edited on 22-8-2020 by Junk_Enginerd]
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JJay
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[*] posted on 22-8-2020 at 09:16


The carbon made from the reaction is called sugar carbon. I've read books that discuss it, and it's supposed to be quite pure, so I would think that any tar would be water soluble.
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macckone
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[*] posted on 22-8-2020 at 10:02


As others have said it is likely unreacted sugar, carbon, water and h2so4.
Some of it may be caramelized sugar as well.
The best method of removing it would be neutralize, rinse, dry then add more h2so4.
The added h2so4 should carbonize any remaining sugar and caramel.
It may require some light scrubbing to separate the remaining carbon from the crucible.
I would use a harder crucible that can be cleaned with piranha solution next time.
Graphite is a poor choice for this reaction.
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