Draeger - 22-8-2020 at 06:53
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?
Junk_Enginerd - 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]
JJay - 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.
macckone - 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.