Production and obtaining cyanides

[Douchermann]

Alkali cyanides can be very useful in an organic chem lab. Unfortunately most suppliers don't/wont sell them, and the suppliers that do, only sell to businesses. This leaves us with two options; Don't do syntheses that involve cyanides (not acceptable), or produce your own alkali cyanides. Of course, alkali cyanides are poisonous and manufacturing them puts you at a greater risk, but with the proper safety precautions this should not be a problem. The problems with home production is the purity of the product. Sure, for us home chemists we don't need 99.9% purity, but we certinaly don't want 50% purity.

 

The best method I know of (and don't flame me for this) would be to react an excess of HCN with an alkali hydroxide/ethanol solution (alkali ethoxide would be formed which would work as well). HCN can be produced by reacting Sulfuric acid with a more available potassium ferrocyanide. The alcohol could simply be boiled off and you'd be left with >98% purity potassium/sodium cyanide. The problem with this is that hydrogen cyanide is deadly poisonous. The reaction needs to be performed outside, unless you have a decent fume cupboard (not just a hood). Also, there should be an efficient system to remove the unreacted hydrogen cyanide. It can be condensed with ice cold water in a very long condenser, followed by leading into a basic solution. A chain of wash bottles with a concentrated sodium hydroxide or sodium carbonate solution would be ideal. Even then it would be wise to leave the general area in which this experiment is being conducted. Make sure you're upwind if you're doing this outside.

 

Sodium and potassium cyanide hydrolyze in water, which is why I went with ethanol instead. It is also soluble in alcohol.

 

Post methods that you know of, or post places that you can get it from.

[weknowpyro]

Just asking, sorry if its off topic.

But isn't hydrocyanic acid (HCN) the stuff the nazi's used in the concentraction camps under the name of zyklon-b.

I would think that just doing this out doors is pretty dangerous unless you have very good saftey equipment and i don't think anyone should do this if they live by other houses lol.

If storing these wouldn't you need to freeze it then? Because i thought HCN reacted and gave off deadly gas at about 21 degrees centigrade.

[Chemguy]

Yes, HCN (or prussic acid) was used in zyklon-B, it also contained a stabilizer which stopped it from evaporated before it was used.

 

HCN with a stabilizer, when exposed to air evaporates. And HCN is highly poisonous itself, so it didn't need to react with any thing.

[Douchermann]

The trick is to try to not any of it escape unreacted. Sure, small ammounts will escape. But it will dissapate(sp) before it gets to you (unless you've got your mouth on the end).

[The_Duke]

The Duke don't mess around, he buys his Sodium Cyanide for $26 a pound

[Rooster]

Start looking for suppliers, thats my tip. I would rather get to know someone in the business than fool around with HCN in my back yard.

[weknowpyro]

Although this is an old thread, I was just wanted to ask something.

I was reading that if nitrogen and acetylene are passed through a series of electrical sparks then it can cause Hydrocyanic acid to form.

N2 + C2H2 -------------->2HCN

However wouldn't the electrical sparks just cause the acetylene to combust?

[rocket]

I wouldn’t think so if pure N2 is used, IIRC acetylene needs 3-80% O2 in the air to combust. Mind you look what happens when it comes in contact with Chlorine.

[h0lx]

The Duke don't mess around, he buys his Sodium Cyanide for $26 a pound 

The Duke is getting ripped off. I can get KCN for 12€ for a kg EDIT: oh and NaCN for the same price.

[Mumbles]

You probably want the acetylene to combust, just with the nitrogen.