Question Intresting observation with Al/Hg reduction

[Wendy]

I was reducng p2np and after adding alkali the freebase separated. I poured the freebase and extracted with non polar solvent anything that's left in sludge. I thought most of it was removed, however after couple of hours more freebase apeared from the spudge. I added that to separate container. odly, it happen again and again. Eventiually, after repeating the procedure i was left with very, very little sludge making my yeilds over 100%

The amph producted was as good as from the first extraction. Really intresting

 

[Heartburn]

Once, I've left my separatory funnel alone in silence, to keep it bubbling in peace overnight. The next day morning, my fate got me busy with daily duties and finally took me over 24hrs to look after the separation process. In short: waiting wasn't worth the yield recoveried. It was looking very similar to the situation described by @Wendy. But I had to tell you the bitter piece of truth. My top organic layer wasn't even been covering whole liquid surface (it was the widest part tbh), but rather looked like nearly orange version of fat drops on hot broth surface, finally filling (bottom meniscus ofc), a little bit over 1.5ccm line on scale (A-class 10ccm meas. cyl.). Bottom ~1inch high layer of dark grey sludge has been bubbling, hardly anything but still noticeable. Mid layer was almost transparent, but also little foggy.

The point is that bubbling of alkalized Rm in separation funnel, comes from the leftover metallic Al is now reacting with NaOH, precipitating insoluble complex named Sodium tetrahydroaluminate (III) and hydrogen. What you had mistaken with with freebase layer was just excess amount of NaOH in water. So i bet that over 60-70% of your final product is just totally inactive salt named sodium sulphate. It is irritant in contact with mucosa!
"Non omne quod nitet aurum est."

 

[Wendy]

Oh yes, it sting like hell in spite of being at right pH of 5,5- 6 !

So is decanting ipa/freebase layer and extracting once with from the sludge optimal?

 

[Heartburn]

When I'm doing the separation, it simply comes to wait few minutes until top layer stops acting like alien version of lava lamp. Dump bottom layer into a jar, then I'm personally adding exactly about (2g anh. Na2SO4 per 10g P2NP) x multiplier of current batch size, to the organic layer, then shake it off for a while. It makes all the grey sludge drops to get dehydrated on salt's surface. eventually the conglomerate made of readily solidifying sulphate and amalgam turds, form something similar to "frit" used in column chromatography. It doesn't clog the funnel's drain valve but acts like a filter leaving crystal transparent yellowish freebase solution. Then i dump the sludge from jar back to SF, if the second round is not so rich in freshly floated freebase layer, I add just 10ml of isooctane (2,2,4-trimethylpentane) or other similar non-polar, high boiling, low vapor pressure solvent, shake again, wait 10-15 minutes and then partially: drain 2-3 inch of height -> swirl SF vigorously to create a vortex -> watch grey mud above top layer is getting ripped off the funnel walls -> repeat as long as needed. Second extraction layer is then poured to glass funnel, narrow leg, gently tapped with cotton frit, and filled low with 2g of anh. Na2SO4. After dry-filter-ing the extract, filter bed should be washed with 1-2ml of previously used extraction solvent and finally combined with 1st extraction layer. Simple, effective, also IMO low cost and barely sus to any gvmnt.

P.S. how much did you yielded with which acid, and from what amount of P2NP, i'm just really curious about raw statistics.