Sciencemadness Discussion Board

HCN produced using an arc?

497 - 11-10-2007 at 20:46

in noticed in "the_war_gasses" pdf it mentions using an "electric sparks" through a mixture of acetylene and nitrogen to produce HCN. it says nothing further about the process. would it work? it seems like a possibly easier method than the others mentioned, and yes realize it is extremely toxic, im not about to try it at home.

Sauron - 11-10-2007 at 20:50

Try reading Ullmann's and Kirk-Othmer's as recommended in the forum FAQ. They detail industrial processes like this, with references. Reading about making HCN will neither kill you nor get you in trouble.

Both encyclopedias are available free on MadHatter FTP.

Antwain - 12-10-2007 at 04:46

Easier than what? distillation of a ferrocyanide? :D

This *may* be of use to industry but I am willing to bet that its useless to the home chemist.

497 - 12-10-2007 at 16:17

yeah youre probably right.

chemrox - 12-10-2007 at 20:48

What happened to adding mineral acid to KCN or NaCN?

Sauron - 12-10-2007 at 21:48

DILUTE mineral acid.

Potassium ferrocyanide is easier to buy, and used to be the main bench scale prep.

Org.Syn. teached the "newer" method you mention.

evil_lurker - 12-10-2007 at 23:05

Actually I think it could be do-able, but yields would suck ass... one MIGHT get 3-5% conversion per pass.

I'm thinking take a PVC "tee" fitting, slip on both ends and FPT in the center.

Take a rubber stopper, fit a luer lock syringe and needle thru the center and wire it up. Then take another stopper, drill it out just a little bit for some small diameter glass or quartz tubing, fit a an electrode wire thru the middle. Then simply put a screw in hose fitting on the end.

What you got is a setup where the gasses are basically injected and forced into the arc stream and any radicals are given time to react before exiting.

Who knows, might work, might not. If it doesn't, who cares, would cost maybe $10 to build, minus the regulators and power supply.

497 - 13-10-2007 at 00:21

yeah test it with the cheap pvc model, then for a little higher grade i was thinking a good long borosilicate tube housing, maybe a neon sign transformer. would it be good to have a partial vacuum? help disperse the arc a bit... maybe refrigerator compressor for that. would surely be interesting. what can one use HCN for anyway? (besides weeding the cannon fodder out of trenches...)

Antwain - 13-10-2007 at 09:54

If you don't know what it is used for then why are you interested in making it? :o

I believe HCN finds some use in organic chem, which right at the moment is outside my area of interest, so I can't remember what exactly it is used for. I find the CN- ion to be much more interesting as it is a very important ligand in coordination chemistry. The ion also finds use as a nucleophile in organic chem, for making nitriles and subsequently carboxylic acids etc.

497 - 13-10-2007 at 10:08

hah well i've seen many instances on this forum where people try to synthesize things that they have little use for...

leu - 13-10-2007 at 19:21

Berthelot disclosed in Comptes Rendus 67 1141-5 (1868) that the optimal results of this reaction were obtained using 10 volumes of acetylene, 14.5 volumes of nitrogen and 75.5 volumes of hydrogen using carbon electrodes :) More details can be found in the attached article, this approach seems less practical than some of the related processes using other hydrocarbons :P

Attachment: berthelot.zip (60kB)
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