09-05-02 01:16
No 352736
Why is ~10g of NaOH used for every 1g of Al foil for the post Al/Hg workup in say the MM synth? (the question actually pertains to basifying an acetic acid Al/Hg in methanol on isosafrole ketoxime) This seems like a crazy excess, is it really needed, or is just reaching a pH of >12 alright? It would seem to me if there's no left over foil (not present, esp if water is used in the Al/Hg), one could drastically cut back on the sodium hydroxide.
What about using something like 3g of NaOH per 1g of foil?
Is there something I'm missing here?
(Hive Addict)
09-05-02 06:09
No 352869
Chromic, Adding smaller amounts is great. If you get it just right then everything will granulate and crash out. Then you can decant the liquid from the granuals and extract the sludge with MeOH. Add the MeOh to the decanted liquid add some brine and extract. much less chance of having an emulsion.
So much game I could sell a hooker some pussy
Vl_
(Synaptic Self-Mutilator)
09-06-02 03:20
No 353278
Well, after doing an Al/Hg on an oxime that didn't precipitate, the foil never fully reacted... yuck. (maybe I should have waited a day on this...)
What I did, was strained (not filtered!) the mix to remove most chunky particles, then added 3g NaOH / 1g foil. Then extracted 2x with toluene... anyways, an emulsion formed. This was a bitch to break up and didn't go away until I filtered, the NaOH/NaCl/bicarb washes did nothing until after filtering (tried it all). I wish I had celite as this was a very slow filtration... (is this OTC anywhere? such a great filter aid...)
But I got there, and after recrystallization the yields are a far cry from normal (something I attribute to the sad state that the oxime was in, usually brings yields for me to 1/3 of what they should be)... but I'm quite happy nonetheless. (All I needed was a few dozen doses for personal)
So, here's some pointers if other people try this "bright" idea:
1) strain to remove any unconsumed foil particles
2) filter the toluene extracts to remove some slimy white powder that causes emulsions (pref. w/celite) (some hydrate of aluminum hydroxide?)
(Title on BackOrder)
09-06-02 07:46
No 353363
you're working with a lot of methanol, and your freebase is soluble in alcohol. You want to add a lot of base and water to make the liquid extremely polar and drive out your freebase.
All paths are the same: they lead nowhere
(Hive Bee)
09-08-02 08:46
No 354172
My mother in 500g ketone runs, (ala MM), I end up using 10L of 30% NaOH, which is shitload less than specified, but before toluene extraction I also add ~10L of water, to increase the polarity, often it depends on how long you have let the rxn run, if overnight then this is heaps but if you stop it after three or four hours (the rxn runs longer at this scale I have found), it often needs more NAOH. Every now and then I observe weird things in the mix, like brown colours or fluffy white suspensions, but these never seem to affect the yeilds.
wacka wacka wacka
(Hive Addict)
09-09-02 03:14
No 354451
An emulsion at the end has always been a sure sign of a failed or poor conversion. CHromic Use a scotchbrite pad for filtering solutions like that soak them in a solvent for a while to remove the green color if that concerns you. however the clolo has never affected swims product. Those dish scrubbers are great. Chem resistant and 4 for a dollar. can't beat that. SOmetimes it takes two layers depending on the consistancy of the sludge. Also swim found it is better to filter the rxn before casification to first remove all the unreacted al. That is what generates a bulk of the heat when basifying in swims experience. you can get to the exrtaction faster.
Vl_
So much game I could sell a hooker some pussy
Vl_