Sciencemadness Discussion Board

mercuric chloride

pip - 8-9-2011 at 09:53

If someone performed an amalgam and was conserned about mercuric chloride remaining in the final product would washing the freebase with water 4x and washing once with a saturated sodium chloride be suffecient or is a recrylstalization nessicary?

My reactant is phenyl 2 butanone (not p2p) if that matters.

[Edited on 8-9-2011 by pip]

[Edited on 8-9-2011 by pip]

weldit - 9-9-2011 at 18:34

mercuric chloride is only slightly soluble in benzene, so if you extract your freebase into toluene or xylene and wash with water and salt solution there will be no mercury

pip - 9-9-2011 at 22:32

thanks

Nicodem - 10-9-2011 at 01:25

Quote: Originally posted by weldit  
mercuric chloride is only slightly soluble in benzene, so if you extract your freebase into toluene or xylene and wash with water and salt solution there will be no mercury

Mercuric(II) salts are strong soft acids which tends to react with soft bases like the Pi-systems of benzene, toluene or other electron rich aromatics via the electrophilic aromatic substitution. It also reacts with the Pi-bonds of alkenes and alkynes as well as other similarly soft bases. The product with benzene or toluene, the corresponding arylmercuric salts, are preferentially partitioned in the organic solvents rather than water.

http://en.wikipedia.org/wiki/Organomercury#Mercuration_of_ar...

pip - 10-9-2011 at 07:05

so recrystalization? or is there another step that can remove the last traces of mercury? I have been using xylene as the nonpolar.

could I just rinse the collected product with clean xylene?

[Edited on 10-9-2011 by pip]

Nicodem - 10-9-2011 at 07:40

Cited from Methamphetamine Abuse: Epidemiologic Issues and Implications (NIDA Research Monograph 115, 1991)
Quote:
Another potential contaminant found in illicitly produced methamphetamine is
mercury. The “mercury method” uses P2P and methylamine, which undergo
condensation in the presence of aluminum foil and mercuric chloride.
Inadequate purification produces a final product contaminated with mercury,
residues of which have been found in varying amounts ranging from zero to
1,300 ppm, in methamphetamine samples from 25 clandestine
methamphetamine laboratories Seized by DEA (Davidson 1983).

There are more recent studies than the refereed one from 1983, but I'll let you to do some searching yourself.
Just in case you don't know what 1300 ppm means: that is 0.13 % mercury!
Quote:
My reactant is phenyl 2 butanone (not p2p) if that matters.

Yes it matters. Please post the complete synthesis with the experimental.

pip - 10-9-2011 at 10:18

I followed methyl man's mdma synthesis from mdp2p except I used phenyl 2 butanone and instead of toulene I used xylene. I wanted to do a reductive amination using the almagum method and settled with the perfectly legal (i hope) phenyl 2 butanone. I want to taste the product like the chemists of the 1800's did but I'd rather be happy knowing I did the reductive amination fine and not taste it if removing the mercury is not possible.

[Edited on 10-9-2011 by pip]

Attachment: Reductive Amination of MDP2P with Al-Hg + Nitromethane.mht (36kB)
This file has been downloaded 1200 times

pip - 10-9-2011 at 17:23

ok, a recrystallization using 99% IPA should leave the mercurated xylene in the IPA correct?

Chordate - 11-9-2011 at 00:03

I'm curious, I've never played with the Al/Hg reduction, but in theory doesn't aluminum already amalgalmate with pure mercury metal? I know the aluminum oxide coat is a hassle but could you pre-treat fine mesh aluminum with a little gallium then add straight mercury metal, could you not?

I'm not sure about the reaction mechanism here. I know with the clemmensen reduction the mercury is just activating towards the zinc and its the other metal which does the reducing. Since either way the system is going to be heterogeneous, is it so important that the mercury be in solution? Or am I making a mistake in thinking the reductions are similar (organometallic is voodoo as far as I am concerned).

Nicodem - 11-9-2011 at 01:12

Quote: Originally posted by pip  
ok, a recrystallization using 99% IPA should leave the mercurated xylene in the IPA correct?

You can't really expect anyone to give you a reliable answer to such a question?
Depending on which of the three possible phenyl-2-butanones you used (there is 1-phenyl-, 3-phenyl- and 4-phenyl-2-butanone), you get different possible products. If you used 1-phenyl-2-butanone, you get 1-phenyl-2-methyaminobutane. This is a known compound, so check the literature for the possible purification ideas. There are also Hive posts from Kinetic, describing the synthesis of this compound (though he used a different route). Check what kind of isolation/purification were used. If you used 4-phenyl-2-butanone, you get 4-phenyl-2-methyaminobutane which is described at the Hyperlab forum and most likely in the scientific literature as well. Always do a literature search before you start any synthesis!
But whatever you do, nobody can guarantee you the absence of mercury. Not even if you would vacuum distil, could one guarantee you no mercury compounds carry over. An analysis is the only one way to get a definite answer, though unfortunately not everyone has an ICP or similar equipment in his garage. So it is about you to make the final decision and take your responsibilities.
Quote: Originally posted by Chordate  
I'm curious, I've never played with the Al/Hg reduction, but in theory doesn't aluminum already amalgalmate with pure mercury metal? I know the aluminum oxide coat is a hassle but could you pre-treat fine mesh aluminum with a little gallium then add straight mercury metal, could you not?

Metallic mercury can not properly activate the whole of the aluminium surface. You would only get small contact area of amalgamation where the Hg(0) drops penetrate the oxide layer (depending on the stirring intensity). Hence, soluble enough Hg(II) salts are used in order to properly and uniformly activate the surface by amalgamation. The amalgamated aluminium is then happy to donate electrons to any substrate demanding them, so to speak.
As far as I know, the only other surface activating method that was demonstrated successful, is the use of an in situ made [CuCl4]2+ complex salt (see the latest discussions at the Hyperlab forum for an example). There was some discussion about using gallium on SciMad, but I don't think anybody bothered reporting back on their experiments.

The Clemmensen reduction similarly employs Hg(II) in order to activate the Zn surface, though I would expect that increasing the hydrogen overvoltage of zinc by amalgamation plays a crucial role as well. If the hydrogen overvoltage is not high enough, the competing reduction of water (generating H2), instead of the organic substrate reduction, is a competing (or major) reaction. Though, I think there are examples of the Clemmensen reduction done ethereal hydrochloric acid which don't require amalgamation.

Chordate - 11-9-2011 at 02:11

Erudite and educational as always Nicodem. Thanks for the response. Kinetics is a harsh mistress. Pity that we aren't all immortal and had the free time to stir a flask for a month before adding our substrates.

pip - 11-9-2011 at 07:20

It was 1 phenyl 2 butanone. oh well on the tasting it wasn't that big of a deal but I'll still do the recrystalization since it is all about the practice of lab techniques anyways. thank-you for the advice.

crap, upon further reading 1-phenyl-2-methyaminobutane is a stimulant I for some reason was under the impression that the extra carbon in refrence to amphetamine made it totally inactive so time to "flush it down the drain" and start over with somthing less legally questionable.

[Edited on 11-9-2011 by pip]

unionised - 11-9-2011 at 08:21

If you bubble hydrogen sulphide through a near neutral solution of the product and don't get visible mercuric sulphide then there's not a lot of mercury there. A good filtration of the solution will remove any HgS and yuo can remove the excess H2S by boiling.

mr.crow - 11-9-2011 at 08:38

The aluminum should reduce all the HgCl2 to Hg. That's what creates the amalgam.

Perhaps get a mercury test kit and test your product before and after recrystalization

pip - 11-9-2011 at 18:51

The mercury test kit sounds like a great idea however I need to find a new ketone to reduce as my last one turned out to make a drug and that was not my intent so I got rid of it.

Chordate - 11-9-2011 at 20:47

Quote: Originally posted by mr.crow  
The aluminum should reduce all the HgCl2 to Hg. That's what creates the amalgam.

Perhaps get a mercury test kit and test your product before and after recrystalization


Pure 0 oxidation state mercury does amalgamate aluminum though.

[Edited on 12-9-2011 by Chordate]

overload - 30-9-2011 at 15:15

Quote: Originally posted by weldit  
mercuric chloride is only slightly soluble in benzene, so if you extract your freebase into toluene or xylene and wash with water and salt solution there will be no mercury
I wouldn't listen to this guy if I were you.