I have some carbon powder. I mix it in solid state with KOH in different mass ratios of 3, 4, 5 and 6. Then the samples were placed in furnace. Vacuum and N2 injection was applied 3 times. Then the furnace was turned on to heat the samples to 800 °C in Nitrogen gas flow for 2 h and 5 °C/min heating rate. Later, the furnace normally cooled down and samples were removed. After this step, sometimes the samples are usual and sometimes there is no carbon remaining!!! Does any body know the reason?
This can only be explained by too high oxygen partial pressure. Furnace has either a leak or your nitrogen contains too much oxygen.
This can only be explained by too high oxygen partial pressure. Furnace has either a leak or your nitrogen contains too much oxygen.
Do you mean with different KOH loading that there is no product? Or that upon repeated attempts of the same experiment that there sometimes is and is not any product?
If it is the prior, then Vadim is correct as your procedure sounds standard. It is also worth checking the tube and boat is dry (if washed), the line is not contaminated, and that your product is not hydroscopic enough to bring extra water in the reaction.
For the latter, temperature and KOH loading has an effect on the yield:
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Perhaps you have a powder of potassium carbide. You can patent your method
2KOH + 3C = K2C2 + H2O + CO
Regards
Jet-Sing M. Lee
sometimes for the same experiment there is product and sometimes there is no product.
Has to do with higher temperature favoring the reverse bouduard reaction taking place in presence of a catalyst, thus converting most of the carbon to CO, (and some CO2). I would also question the purity of your gases
What is the remaining ('K-X', precipitates?), in the cases when there is 'no carbon' ?
Also, what is the crucible and is it the same (quality ?) in all cases ?
Ioannis Samaras Hi sir.
The crucible is made of nickel. Almost there is no precipitation. It looks like that it is vaporized. But in lower temperatures there is no problem observable.
Waqas Hassan Tanveer I think your words are right. Because in lower activation temperatures there is no problem.
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