approx. double the amount nitroalkene of Heavy Duty, non-stick aluminum foil is cut into/paper shredded(easier of the two) ~1x1cm squares. Then the cut foil is added to a blender and allowed to be chopped for a minute or so. This allows the outer coating of aluminum oxide to be chipped off and exposes the elemental aluminum underneath so the mercuric salt can stick to it thus preventing more aluminum oxide from forming.
Now we need to prepare the nitrostyrene for the amalgam. Mix 10x foil amount GAA + 8x IPA + your nitrostyrene(which should be half the amount of foil). It needs to be incubated until the solution is fairly hot(not boiling!) for everything to dissolve so it pours nicely into your amalgamation flask. Why can't you just dump the powder in? Well, solvating the styrene in GAA and IPA makes it react more evenly and efficiently because it's ionized which will work perfect for the hydrogen being produced on the aluminum.
The previously chopped foil is added to a large flask(at least 1000ml) to prevent overflow(and it'll foam like hell trust me). Now to this add a dash of any mercuric salt(I used HgCl2 because of it's high solubility), then 4x the amount of foil of either IPA, ethanol or methanol(methanol has a higher solubility so I used MeOH) and same proportion(4x) of dH2O. Ex: 40ml MeOH + 40ml dH2O.
At this point the amalgam is ready. Let it sit somewhere for 15-30 minutes. By this point in time you should see little hydrogen bubbles. This means the amalgam is successful and the hydrogen reduction is occuring where the foil meets the solvent(the alcohol). When the bubbles start to occur very rapidly dump in the prepared styrene solution all at once. This will insure everything reacts uniformly.
The whole reduction takes ~30-60min from start to end. The color should start from a yellow/orange->green/yellow->black/grey. If this is your situation then the reduction was most likely successful. Unreacted styrene's refraction index is green which means it didn't make it all the way. If this happens to you and your solution is still green add another dash of mercuric salt and wait for the rxn as before. Once everything slows down to a halt and no more hydrogen evolution is present prepare a 25% KOH/NaOH solution and add it to the post-reduction flask.
This will basify the reacted aluminum(and also strongly exothermic) into aluminum hydroxide and the acetic acid into NaAc making the solution now MUCH easier to filter. This will also form the freebase of your amine. One way to tell if your reduction was successful is if two phases form: the upper should be light, and the bottom should be dark. Whip out the buchner and prepare to use quite a few filter paper disks. Hook the buchner to a vac pump(the hand pump takes forever) and pour in portions of the rxn flask. You're going to have to change the filter paper when it cakes over into a grey/black sludge. It's a good idea to double stack filter paper as they seem to last longer this way and filter better. After vac filtering your filtrate should not be dark at all. Mine was always a very light color but your amine color may vary.
Once the filtrate is isolated, A/B extract as usual to obtain the freebase or salt. The pic of the sep funnel with a lower yellow phase is the amine freebase post-workup solvated in DCM.
-PStain.
Now we need to prepare the nitrostyrene for the amalgam. Mix 10x foil amount GAA + 8x IPA + your nitrostyrene(which should be half the amount of foil). It needs to be incubated until the solution is fairly hot(not boiling!) for everything to dissolve so it pours nicely into your amalgamation flask. Why can't you just dump the powder in? Well, solvating the styrene in GAA and IPA makes it react more evenly and efficiently because it's ionized which will work perfect for the hydrogen being produced on the aluminum.
The previously chopped foil is added to a large flask(at least 1000ml) to prevent overflow(and it'll foam like hell trust me). Now to this add a dash of any mercuric salt(I used HgCl2 because of it's high solubility), then 4x the amount of foil of either IPA, ethanol or methanol(methanol has a higher solubility so I used MeOH) and same proportion(4x) of dH2O. Ex: 40ml MeOH + 40ml dH2O.
At this point the amalgam is ready. Let it sit somewhere for 15-30 minutes. By this point in time you should see little hydrogen bubbles. This means the amalgam is successful and the hydrogen reduction is occuring where the foil meets the solvent(the alcohol). When the bubbles start to occur very rapidly dump in the prepared styrene solution all at once. This will insure everything reacts uniformly.
The whole reduction takes ~30-60min from start to end. The color should start from a yellow/orange->green/yellow->black/grey. If this is your situation then the reduction was most likely successful. Unreacted styrene's refraction index is green which means it didn't make it all the way. If this happens to you and your solution is still green add another dash of mercuric salt and wait for the rxn as before. Once everything slows down to a halt and no more hydrogen evolution is present prepare a 25% KOH/NaOH solution and add it to the post-reduction flask.
This will basify the reacted aluminum(and also strongly exothermic) into aluminum hydroxide and the acetic acid into NaAc making the solution now MUCH easier to filter. This will also form the freebase of your amine. One way to tell if your reduction was successful is if two phases form: the upper should be light, and the bottom should be dark. Whip out the buchner and prepare to use quite a few filter paper disks. Hook the buchner to a vac pump(the hand pump takes forever) and pour in portions of the rxn flask. You're going to have to change the filter paper when it cakes over into a grey/black sludge. It's a good idea to double stack filter paper as they seem to last longer this way and filter better. After vac filtering your filtrate should not be dark at all. Mine was always a very light color but your amine color may vary.
Once the filtrate is isolated, A/B extract as usual to obtain the freebase or salt. The pic of the sep funnel with a lower yellow phase is the amine freebase post-workup solvated in DCM.
-PStain.