Hom much of a problem is mercury contamination when using Al/Hg method?

[The_Observer]

Hi, I would like to ask more experienced people on this forum about mercury contamination and toxicity. My plan is to reduce P2NP with aluminum amalgam (Al/Hg method). I'm however a little concerned about the contamination. I haven't fount any reliable sources on this topic. Suppose I washed the amalgam with remaining mercury nitrate/chloride salts with water in initial step many times, so no water soluble salts should remain. Is there any contamination risk from the metalic mercury present in the amalgam? If so, how much of a problem is that? According to my knowledge metallic mercury shouldn't be so toxic.. Do any of you have any measurements etc about the contamination in the product made by this method? If so to which extent? If it is a problem how should I mitigate this? Does repeated recrystallization/wash of the product helps? Maybe cleaning by acid/base method? I would like not to poison myself and the customers by heavy metals Thanks for your time and response. Maybe it is stupid question but I would like to be on the safe side if possible...

 

[octagon]

It has been discussed on this forum before, and Patton said his GCMS returned negligible amounts of mercury in the product. There's also a good chapter in the strike books (dunno if total synthesis 1 or 2) but it's about the in situ reduction of methylamine from nitromethane using Al/Hg. There he covers washing the freebase with water at. least 4 times to get all water soluble Hg salts.

If you steam distill your base you should be fine as well I think. Otherwise the risk is pretty low regarding the end product and you can always dilute some product with water and use a quick test (tsp water analysis strips, 20 bucks on Amazon) or send it in to a lab (only for Hg test, prob. 60-100 bucks, don't really know tbh).

My worries would be focused on you lab, if it's a living space for you or someone else and you spill mercury that might actually become a problem. Even though, I would still think this really starts to be something to consider, if you plan to do the reaction more often. Then obviously a good fume hood and maybe even a sulfur carbon air filter might be adequate, depending on your situation. (According to some parents normal activated carbon isn't that good at filtering mercury.


Hope this helps, not an expert, so take this with a grain or salt

 

[loadingST]

I will recomend you, afther the reactions ends, leave it for 24h, it will settle, all the sludge will setle to the bottom with the now elemental mercury, do not disturb much and filter gravity, then basify the reaction mixture and freebase will precipitate on top with some of the alcohol.

 

[OneTensionSkyRed]

The problem is not so much with mercury salts but with organic mercury contamination. For example Na/Hg amalgam can give diisopropylmercury when reacted with acetone. Mercury acetate and similar non-ionic mercury salts can react with alkenes to give organomercury. So that is certainly a possibility here. Also, steam distilling or vacuum distilling does not clean the product from organic mercury completely.

 

[loadingST]

Methylmercury is also a possible side product here, depend on condition, if done right, its easy to remove any mercury contamination.

 

[Chemdog010297]

Make sure u separate the solvent from the water with mercury in it and it isn’t a problem. Dry the solvent and filter it. Make sure it has no water in it at all. And ur good. Or u can substitute nickel chloride instead of mercury and hcl instead of acetic acid.