Actually it is quite the opposite m'ilady. Since a very popular reaction type for either reduction of P2NP, or reductive amination of P2P (phenylacetone) or reduction of phenylacetone ketoxime to amphetamine (in the last case) or methamphetamine (or ethylamphetamine for people with a preference for it) is reduction of the P2NP (1-phenyl-2-beta-nitropropene) or reductive amination of P2P (1-pheny-2-propanone/P2P/phenylacetone) with either an anhydrous alcoholic solution of methylamine (for methamphetamine) or ethylamine (for N-ethylamphetamine) or alternately, one can also employ nitroparaffins, nitromethane and nitroethane respectively for the same process, as the nitroalkanes undergo reduction of the nitro group to an amine, and in both cases the reaction proceeds via an intermediate imine, which is reduced to the alkylamine (I.e methyl/ethylamphetamine) and the way this is often done, is by preparing an aluminium amalgam, using aluminium foil, cut up into about inch-wide squares and folded up a few at a time very loosely into gently folded balls, and reacted with a solution of a divalent mercury salt, such as (most commonly) HgCl2, mercuric chloride (mercury (II) nitrate is the other commonly used salt although I have a hunch it ought to be less than ideal given that the reaction is a reduction, whilst the nitrate anion is an oxidizer) although how much effect this would have in practice is debatable, and more or less a personal musing of mine, since in an Al-Hg reduction only a very small amount of mercury (II) salt is used, sometimes, depending on the scale of the reaction, and the substrate, its just added off the tip of a knife point.
The role of the mercuric salt is to depassivate the aluminium, since Al is a very reactive metal and in the right conditions, a powerful reducing agent, and as such, being a powerful reducing agent it means its also very easily oxidized, and aluminium is just that. Once first exposed to oxygen it forms a very fine surface layer of aluminium oxide that, as its said, 'passivates' the aluminium, its only microns thick but it also near enough instantly reforms if damaged.
When Hg is present, it destroys this very thin passivating surface layer of oxide and allows reaction with the bare aluminium surface, and prevents the Al2O3 layer reforming, when used as an amalgam this allows the use of aluminium as a powerful reducing agent. The drawback of the Al/Hg is that mercury is very toxic, and a pollutant as well. And whilst the metal mercury itself is primarily toxic via the vapors, rather than bulk metallic Hg, (although the vapor pressure is actually significant enough, I've seen an ultraviolet photograph of mercury once before and it showed fumes billowing off like crazy) its a lot less hazardous than its salts, which being soluble are absorbed much more easily than mercury metal. And of the two common oxidation states, Hg (I) [mercurous] is the lesser hazard, whilst mercuric (Hg (II) ) salts are a LOT more toxic, HgCl, mercurous chloride or calomel, was used as a medicine in olden times although recognized as toxic even in some medical manuals of mine from the 1700s, the deadly nature of 'corrosive sublimate', as HgCl2 (mercuric chloride, the divalent chloride of Hg) [Hg generally displays just the two oxidation states, apart from Hg (0), in mercury metal itself, the two being Hg (I) (mercurous) and Hg (II). (mercuric) and of the two, mercuric salts are FAR more toxic. Its probably the only item in my lab that actually causes me to feel fear working with it (HgCl2) and I've only maybe a few grams at most, or I did when I first bought the last lot I purchased, and less than that now, having used some). Stuff gives me the fucking creeps. Its just so damn toxic, I don't want anything to do with it if I can help it.
But there are other ways to deprive that particular felid of its epidermis. That do not involve mercury.
Such as for example direct reduction of the 1-phenyl-2-beta-nitropropene, that can be done in a one-step reaction, plus workup using lithium aluminium hydride, or in two steps using borohydride to reduce the double bond to give 1-phenyl-2-beta-nitropropAne, the saturated nitroparaffin, and then reduction of the nitro group using an acidic dissolving metal reduction, such as fine iron dust in hydrochloric or glacial acetic acid with some ferric choride hydrate added as a catalyst and the slurry mechanically stirred (since the iron is of course magnetic, one can't use magnetic stirring) from overhead whilst kept at 80 'C for 2.5 hours or so. This reduces the nitro group to an amine, forming amphetamine from 1-phenyl-2-nitropropane, and if the same reaction conditions are used on P2NP (1-phenyl-2-beta-nitropropEne) it undergoes a rearrangement as well as a reduction, to give the ketone, phenylacetone, 1-phenyl-propan-2-one, which can be used in several ways, either other methods of reductive amination after preforming the imine with an anhydrous alcoholic solution of methyl or ethylamine for meth/ethamphetamine respectivey, whilst using a suitable dessicant agent, since forming the intermediate imine generates an equal quantity (molar) of H2O, and the simple phenyl-2-iminopropanes are not stable against hydrolysis and the very water they produce as they are formed will destroy them unless the water be trapped, either by use of a dessicant, or by azeotropic distillation;
And then borohydride can be used to nicely cleanly reduce the imine in anhydrous iPA or most likely in THF or ether.
Or for plain un-alkylated primary-amine amphetamine from P2NP, you just employ the acidic iron/ferric chloride reaction to give phenylacetone, extract it with dichloromethane (aka methylene chloride, or dichlor for short, or else chloroform can be used also, but I prefer DCM, its cheaper and its boiling point is lower) and the DCM or CHCl3 washed with aqueous 10-20% sodium hydroxide (caustic soda) solution repeatedly until the color is discharged (it typically looks really dark when first done and the acid portion is really black looking or dark rusty orangey and thick, slurry like. But the DCM or chloroform easily extracts the P2P, and that separated off chlorinated hydrocarbon nonpolar layer repeatedly washed with the hydroxide, cleans it up, then the DCM/chloroform is distilled off, and ideally the P2P yielded thus is fractionally distilled under vacuum to purify it, although if not possible then the ketone can also be made into its bisulfite adduct using sodium bisufite or metabisufite in aqueous alcohol, crystallized out, due to its insolubility, and washed further with various solvents (ketone bisufite adducts are piss poor soluble in most solvents) and then can be regenerated to reform the ketone using a mild base such as sodium or potassium carbonate solution, and re-extracted into DCM, dried over sodium sulfate, magnesium sulfate etc. to remove the water traces,
Then the dessicant should be, if one is thorough in recovering as much as can be, washed with further anhydrous solvent to get the last bits of P2P, then the phenylacetone thus cleaned reacted with an alcoholic solution of hydroxylamine, to form the ketoxime, and after isolation of the oxime (distillation off of the alcohol, and washing free of unreacted hydroxylamine and unreacted base, sodium acetate working nicely enough to deprotonate the hydroxylamine hydrochloride or sulfate used, to allow it to react, in freebase form (you don't want to store pure, neat hydroxylamine freebase as its unstable and has in the past caused explosions in industrial plants, particularly when heated, so NH2OH salts are used instead, and deprotonated with a mild base to form the freebase in-situ at room temperatures or warmed and it reacts as soon as its formed thus averting explosions)
And the oxime, as with most ketoximes or aldoximes are insoluble as fucking hell in H2O, although they can be very difficult to crystallize indeed, but they can be used, as long as they are clean and pure, in their favourite state (I.e oiled out and desparately doing their damndest to stay as a thick oily viscous liquid-oily blob), as they are, without needing to crystallize the ketoxime, and it really is exceedingly difficult to crystallize even when very pure,
Oximes are just like that generally, but it doesn't matter, one simply makes sure it is free of H2O, then takes it into a solution in anhydrous ethanol, and reduces the phenylacetone ketoxime to the amine (amphetamine) by means of the Beaveault-Blanc reduction (sodium metal in anhydrous ethanol, the substrate being dissolved in the EtOH and then the sodium added carefully in small pieces, under inert gas, preferably argon, as its easier to form a protective blanket due to its being much denser than air, although nitrogen, or even helium, with care, can be used)
The acidic iron methods are clean, from a toxicological point of view, much nicer than mercury-based-anything.
The workup if going with the phenylnitropropAne is a bit of a mess, and theres always a lot of excess iron and iron oxide slop to be vacuum-filtered with fine filter paper, and plenty sour-smelling highly acidic slurry to process, but it is much safer than mercury reactions to work up. And the disposal of iron oxides and iron environmentaly speaking is not problematic, since its basically rust and iron ore, not deadly toxic Hg salts and Hg amalgam. The dichloromethane or chloroform are simply distilled off, washed several times with caustic solution and with brine solution and with H2O to neutralize the PH and redistilled for re-use (disposal into the environment is not a good thing, chlorinated hydrocarbons are bad ozone depleters and environmentally unfriendly so the prudent chemist recycles it wherever possible.
(and NEVER burns them, its alright for some solvents, hydrocarbons, ethers etc. but halogenated hydrocarbons can form some really nasty things when burning, such as phosgene (carbonyl chloride) or in the case of chlorofluorocarbons, fluorophosgene and hydrogen fluoride gas,
and these are singularly lethal, phosgene in fact having been used as one of the early chemical weapons in the days of trench warfare, as a replacement for and advance on chlorine gas, when gas masks that protected the soldiers from Cl2 gas were in wide use, carbonyl chloride (phosgene), was used as a replacement for chlorine gas, and unlike Cl2, which stings, makes one's eyes run like crazy nose run and sting, and makes you cough and is generally irritating at concentrations far less than are sufficient to be lethal. Phosgene on the other hand, C(=O)Cl2, carbonyl dichloride, has very, very little odor, and what it does have by way of smell, is not particularly alarming either, it smells of musty hay, faintly (I have smelled it, once, and the simple fact I did scared the fucking shit out of me, I thought I was a dead man still walking, since the effects of phosgene are delayed significantly after exposure by many hours often), and there is no irritant property to it, nothing to warn you whatsoever.
The reason I am still alive, after accidentally producing a very small amount of phosgene one time is because, and ONLY because I knew what the smell is due to reading of the history of chemical warfare, so I knew what to be alert to, I smelled musty hay, faintly as can be, a mere hint, and I RAN for it, grabbing my gas mask on the way and slamming it on like there was no tomorrow. If I hadn't, there would not have been. Not for me, at least. After I got the mask on, I vented the lab, completely, opening every window, setting pumps up inside to suck in inside air and vent it out, setting up scrubber tanks, everything. And of course clamping down on, and stopping that reaction proceeding as fast as could be done and connecting the outlet of the container it was done in to a scrubber tank to destroy any further produced (accidentally, I'd NEVER deliberately produce phosgene, or use it as even a transient, in-situ generated intermediate in a reaction. Its just scary fucking stuff. Just thinking about that faint smell that day for the few seconds smelling that tiny trace is enough to make my hands shake, because that was too damn close. If I hadn't known my military history relating to the WWI-WWII periods I would not now be typing this post, as I'd have died of fulminant pulmonary oedema, drowning on dry land, with my lungs filling with my own blood plasma.
Thankfully, I am well read in a wide variety of subjects of all sorts, and I'm bloody quick on my feet when I have to react instantly to a hazardous situation of that kind, I've developed some nigh supernatural reflexes over the years since my childhood
When it comes to accidents involving either highly toxic substances, they very rarely happen, I am cautious by nature, in terms of my lab practices, careful and methodical. On the rare occasion something does happen involving a deadly toxin or spill of something corrosive as hell (or worse, both corrosive AND toxic,
When Murphy decides to be a bastard of a law enforcement officer that particular day
) then I've got by any accounts quite some reflexes ingrained in me by dint of both much reading, and unlike my early forays as a kid into chemistry, much more learning and importantly, practical experience, so when it comes down to something un-preventable like a flask failure due to badly tempered glass, that could happen to anybody unfortunate, and resultant liter or two of boiling concentrated sulfuric acid and chromyl chloride at about 140-150'C being launched downwards as a flask literally splits in half with the bottom dropping out due to thermal shock, despite the glass being borosiicate, but the individual piece being defective in its manufacture. Shouldn't happen, did. And if I'd been any slower, I'd have melted myself from the waist down. And melted my balls to carbon ash for sure, probably given myself cancer in as many places as a tumor could grow, and if not lucky, burnt my legs and waist down to bare bones, and maybe carried on going, whilst choking death on the CrO2Cl2.
As it was, I got away unharmed, with the only damage being the wooden bench being burnt to char, and saturated in hexavalent chromium dross, which had to be cut out of the bench with a saw, as if it were itself a malignant tumor, and a suitably shaped and sized slab of wood inserted and screwed in, whilst the chromium salts were carefully leached out of the wood-ash and recovered as much as possibe before the remainder and wood ash slops were sent for hazmat chemical disposal at the relevant section of the municipal waste dump as the toxic waste they were.
So, as for the two-step NaBH4 reduction of P2NP then Fe/acid/FeCl2 reduction to amphetamine, its a clean route, and the same route without borohydride, on plain P2NP to give the ketone, then oximation, or borohydride reductive amination, these are clean methods. Hg free. General moral-Hg is nasty in general and ideally avoided if at all possible. And you, miss K my dear, deserve far better than even the most meticulously purified product prepared via Al/Hg.
And besides, I don't like doing that reaction for any substrate, its temperamental, one time barely starting, the next taking off like a bloody cannon shot and only stopping near the top of several METERS of condensers. One time so slow as to need hotplate heating and a blowtorch, the next so rapid and exothermic that the flask needed periodic immersion in an ice-salt-antifreeze cryo bath to stop a Hg-slop flash-boiling and taking off like a fucking space rocket blastoff. Which needless to say, would splatter toxic slop everywhere that'd be a nightmare to clean. Especially the portion splattered on the ceiling.
Its also a shitbag to extract from, a shit to filter, and what is being filtered is a nasty slurry of hard-to-separate fine aluminia soaked in mercuric fucking chloride. In short, its the next worse thing to bathing my sandblasted ball-sack in the remains of a freshly-dead ebola virus victim having been just ground to human hamburger in a woodchipper and blender. Al-Hg amalgam reductions really 'aren't my cup of tea' as we say over here. Never had much luck with them either. It just isn't a reaction that like me, any more than I like IT.
