Leben - 19-8-2014 at 21:26
I had been searching for a fairly facile method for amateur chemists to prepare alkaline metals and I stumbled upon this NurdRage video that I believe
someone here posted. Oddly enough this video is gone from NurdRage's channel but is uploaded here:
https://www.youtube.com/watch?v=JAo2F9ymKXA
This synthesis is particularily interesting, but there is one thing I am trying to wrap my head around. NurdRage mentions the reaction slowing to a
halt without the alcohol catalyst. Does anyone know why? My first speculation is that the alcohol helps to dissolve hydroxide to get it to float
around in solution and come into contact with more Mg, where as since the mixture was hardly mixed, simply heating the reaction would not act to bring
all the reagents into contact.
If this above is the case, then I am still unsure why the potassium spheres turn black in the absence of the alcohol. Do they perhaps react with
excess water in the solution to form a weird black layer of KOH? I'm not sure why it would be black, but a KOH layer could be dissolved by the alcohol
to go and react with Magnesium, in a way. The only reason I don't think this is the case is because the black layers seem to form constantly when no
air/moisture is entering the system. He mentions that only tertiary alcohols work for this reaction, and I wonder if that could be because primary and
secondary alcohols react with the potassium too quickly. He mentions having to continually add the alcohol and mentions it is slowly consumed.
If the solubility of the hydroxide is the limiting factor, I wonder if a strong stirring could allow the reaction to go forward without the need for a
catalyst.... that would be interesting to try.
Does anyone have experience with this synthesis or insight into the role of the alcohol catalyst?
violet sin - 19-8-2014 at 21:43
https://www.sciencemadness.org/whisper/viewthread.php?tid=14...
Leben - 19-8-2014 at 21:47
Completely overlooked the sticky.
Mods feel free to merge it, if it is suited.