Sciencemadness Discussion Board
Not logged in [Login ]
Go To Bottom

Printable Version  
Author: Subject: Synthesis of zinc amalgam for Clemenson reduction
bluamine
Hazard to Others
***




Posts: 176
Registered: 17-8-2015
Member Is Offline

Mood: No Mood

[*] posted on 5-3-2022 at 04:55
Synthesis of zinc amalgam for Clemenson reduction


Hi everyone!!
Can someone tell me how to make zinc amalgam?! Is it similar to the way of making aluminum amalgam?
View user's profile View All Posts By User
unionised
International Hazard
*****




Posts: 4918
Registered: 1-11-2003
Location: UK
Member Is Offline

Mood: No Mood

[*] posted on 5-3-2022 at 14:19


Does this help?
http://orgsyn.org/demo.aspx?prep=CV4P0203
View user's profile View All Posts By User
Metacelsus
International Hazard
*****




Posts: 2502
Registered: 26-12-2012
Location: Boston, MA
Member Is Offline

Mood: Double, double, toil and trouble

[*] posted on 6-3-2022 at 05:03


See pages 4 and 5 of my old TEMPO synthesis here: https://www.sciencemadness.org/talk/viewthread.php?tid=62358

The yield was crap but I did get my product.

Quote:

In a test tube, 0.514 g mercury was dissolved in 0.7 ml 90% nitric acid.
Then, 4.960 g of the product from Step 1 was dissolved in a flask with 25 ml methanol. 17.053 g zinc powder, the mercuric nitrate solution, and a magnetic stir bar were added to the flask, which was fitted with a reflux condenser and an addition funnel containing 45 ml 12M hydrochloric acid. The flask was heated to reflux, and then 10 ml of the acid were added quickly. The rest of the acid was added slowly over 3 hours, with vigorous magnetic stirring.

Over this time, all of the zinc dissolved, and the mercury was reduced back to metallic form. When the reaction mixture had cooled, it was decanted from the mercury, and 10M sodium hydroxide solution was added until it was basic to litmus paper (pH ~9). A white precipitate of zinc hydroxide formed. The precipitate was filtered out, and the solution was extracted with 3 10 ml portions of toluene. Then, the toluene solution was extracted with 3 5 ml portions of 3M hydrochloric acid. The acid was evaporated under vacuum to give 1.658 g white powder. The powder was recrystallized from isopropanol to give 1.194 g colorless crystals.




As below, so above.
View user's profile View All Posts By User
SWIM
International Hazard
*****




Posts: 970
Registered: 3-9-2017
Member Is Offline


[*] posted on 6-3-2022 at 09:58


Used to use 5% mercuric chloride.
Just stir with the mossy zinc.

I used to use those blue triangular mercuric chloride tablets from Merck.
They used to be available on Ebay as antiques, usually from shut down old pharmacies in the midwest.

Don't see those around much anymore, but I'm sure regular mercuric chloride will do fine.

Checked Ebay, and the only thing I saw was a ridiculously expensive empty bottle.
Really makes me wish I'd hung onto my empties.

I do believe I've still got a couple of full ones somewhere.
If you find one, it won't look like pills any more as the chloride just sublimates around the bottle over the years.
The blue material is minimal (A dye added for safety purposes) and didn't seem to effect anything I ever used it for.



s-l1600.jpg - 197kB

I see the bottle says Lilly, not Merck.
Thought they were Merck.


[Edited on 6-3-2022 by SWIM]

[Edited on 6-3-2022 by SWIM]




View user's profile View All Posts By User
bluamine
Hazard to Others
***




Posts: 176
Registered: 17-8-2015
Member Is Offline

Mood: No Mood

[*] posted on 8-3-2022 at 07:37


Quote:
Quote: Originally posted by unionised  
Does this help?
http://orgsyn.org/demo.aspx?prep=CV4P0203


Yes it does, but look, it talks about the reduction itself while I'm talking about the synthesis of its catalyst.
View user's profile View All Posts By User
bluamine
Hazard to Others
***




Posts: 176
Registered: 17-8-2015
Member Is Offline

Mood: No Mood

[*] posted on 8-3-2022 at 07:39


Quote:
Quote: Originally posted by Metacelsus  



In a test tube, 0.514 g mercury was dissolved in 0.7 ml 90% nitric acid.
Then, 4.960 g of the product from Step 1 was dissolved in a flask with 25 ml methanol. 17.053 g zinc powder, the mercuric nitrate solution, and a magnetic stir bar were added to the flask, which was fitted with a reflux condenser and an addition funnel containing 45 ml 12M hydrochloric acid. The flask was heated to reflux, and then 10 ml of the acid were added quickly. The rest of the acid was added slowly over 3 hours, with vigorous magnetic stirring.

Over this time, all of the zinc dissolved, and the mercury was reduced back to metallic form. When the reaction mixture had cooled, it was decanted from the mercury, and 10M sodium hydroxide solution was added until it was basic to litmus paper (pH ~9). A white precipitate of zinc hydroxide formed. The precipitate was filtered out, and the solution was extracted with 3 10 ml portions of toluene. Then, the toluene solution was extracted with 3 5 ml portions of 3M hydrochloric acid. The acid was evaporated under vacuum to give 1.658 g white powder. The powder was recrystallized from isopropanol to give 1.194 g colorless crystals.


That would be great if it can work. I thought it would be more complicated though.
But unfortunately I don't have toluene anymore so It will be much better if I can use another solvent instead
View user's profile View All Posts By User
SWIM
International Hazard
*****




Posts: 970
Registered: 3-9-2017
Member Is Offline


[*] posted on 8-3-2022 at 11:00


Quote:
Quote: Originally posted by bluamine  
Quote: Originally posted by unionised  
Does this help?
http://orgsyn.org/demo.aspx?prep=CV4P0203


Yes it does, but look, it talks about the reduction itself while I'm talking about the synthesis of its catalyst.


See note 1 in this reference.
It is explicit instructions for making the catalyst.
1500 grams zinc in 600 ml 5% mercuric chloride for 2 hrs and filter and use immediately.

Sounds pretty much like what I did, except I didn't wait that long, and I used blue OTC mercuric chloride.
And my zinc was mossy, but That probably isn't a big deal.

Look, if you're really pinched for supplies zinc and mercury can be agitated together while HCl is added to make zinc amalgam.
You probably get different proportions doing it this way, but it does work for some applications.
This was sort of a last resort back when mercury was easy to get in metallic form but the salts were harder to find.




View user's profile View All Posts By User
unionised
International Hazard
*****




Posts: 4918
Registered: 1-11-2003
Location: UK
Member Is Offline

Mood: No Mood

[*] posted on 8-3-2022 at 11:38


Quote:
Quote: Originally posted by bluamine  
Quote: Originally posted by unionised  
Does this help?
http://orgsyn.org/demo.aspx?prep=CV4P0203


Yes it does, but look, it talks about the reduction itself while I'm talking about the synthesis of its catalyst.

Were you unable to see the notes?
"The amalgamated zinc may be prepared by adding 1500 g. of clean granulated zinc to 600 ml. of 5% mercuric chloride solution. After standing for 2 hours with occasional shaking, the liquid is decanted and the zinc is used immediately."
View user's profile View All Posts By User
bluamine
Hazard to Others
***




Posts: 176
Registered: 17-8-2015
Member Is Offline

Mood: No Mood

[*] posted on 9-4-2022 at 06:58


Quote: Originally posted by unionised  
[
Were you unable to see the notes?
"The amalgamated zinc may be prepared by adding 1500 g. of clean granulated zinc to 600 ml. of 5% mercuric chloride solution. After standing for 2 hours with occasional shaking, the liquid is decanted and the zinc is used immediately."

Oh I just thought I've read that before and didn't find what I'm looking for
Thank you I'll try it then
View user's profile View All Posts By User
Antiswat
International Hazard
*****




Posts: 1616
Registered: 12-12-2012
Location: Dysrope (aka europe)
Member Is Offline

Mood: dangerously practical

[*] posted on 17-4-2022 at 10:45


mercury, gross. using mercury seems like playing russian roulette while beating yourself to death with the gun as you take an infinite amount of turns. i dont see why galinstan isnt used instead? gallium-indium-tin alloy, now im not sure if gallium can be used as a salt like mercury can, and frankly.. why not just drip in some HCl to the zinc? mercury is something i hope to never have nightmares about.



~25 drops = 1mL @dH2O viscocity - STP
Truth is ever growing - but without context theres barely any such.

https://en.wikipedia.org/wiki/Solubility_table
http://www.trimen.pl/witek/calculators/stezenia.html
View user's profile View All Posts By User

  Go To Top