I'm posting this in the "beginnings" section because I don't think this is worthy of a full scale discussion.
I wanted to carry out a reaction that requires a small amount of decently pure powdered carbon. Now, obviously charcoal is a very available source of
carbon, but in this case the ash causes a few complications. Long story short, I can't use charcoal.
So I decided to make my own powdered carbon by another method. I dehydrated sugar, which in theory should leave me with a piece of pure porous carbon.
I assumed that this form of carbon would be just like charcoal except that it would not leave any ash residue when burned. Except that this carbon
powder does not burn at all.
It behaves much like graphite, it glows when inserted into a flame, but does not get consumed.
Any ideas as to why this form of carbon behaves this way?Pulverulescent - 25-4-2012 at 14:56
Quote:
It behaves much like graphite, it glows when inserted into a flame, but does not get consumed.
Any ideas as to why this form of carbon behaves this way?
An ordinary flame doesn't have what it takes to ignite pure carbon . . . White Yeti - 25-4-2012 at 16:11
An ordinary flame doesn't have what it takes to ignite pure carbon . . .
I'm using a flame hot enough to light charcoal, I've done it several times as control. The hottest point in the burner I'm using is around 800C, more
than enough to get the job done. There must be another factor.
I'm thinking porosity may be a factor? But even when I crush up the carbon it doesn't burn, it just glows.Vargouille - 25-4-2012 at 18:08
I don't believe that regular charcoal is pure carbon. It's pretty close, but it could be that whatever it has that makes it not pure carbon allows it
to react at lower temperatures. Could someone else chime in on the specific make-up of charcoal? barley81 - 25-4-2012 at 18:20
What did you use to dehydrate the sugar?Polverone - 26-4-2012 at 11:46
I believe that the ash-forming salts present in ordinary charcoal have a catalytic effect on the burning. You might compare against charcoal made from
sugar containing 5% sodium carbonate.barley81 - 26-4-2012 at 11:56
That reminds me of an experiment in which sugar is burned. A sugar cube coated in baking soda burns much more readily than an uncoated sugar cube.Adas - 26-4-2012 at 12:45
That reminds me of an experiment in which sugar is burned. A sugar cube coated in baking soda burns much more readily than an uncoated sugar cube.
This is merely due to fact, that the ash can act as a wick for the molten sugar, IMO.Pyro - 27-4-2012 at 14:36
i find the best source of carbon is ball milled cokes,
you find cokes almost anywhere, lots of carbon, cheap (free really, just pick up a few lumps at the edge of a pile :p) White Yeti - 27-4-2012 at 17:28
I thought you'd never ask
It's an isopropyl alcohol burner, made from the lid of a mason jar and a little steel wool. It produces a clean blue flame as shown, and it is hot
enough to be considered a bunsen burner for all intensive purposes. Here's the spectrum of copper:
The only downside is that sometimes the flame is golden from the presence of iron in the steel wool, but if you're heating stuff up, it doesn't really
matter.
"I believe that the ash-forming salts present in ordinary charcoal have a catalytic effect on the burning. You might compare against charcoal made
from sugar containing 5% sodium carbonate."
I tried dehydrating sugar mixed with a small amount of baking soda and then tried to ignite it. The result was the same, a porous black mass,
impervious to ignition was obtained.
