Sciencemadness Discussion Board

KCN/NaCN versus other cyanides in the synthesis of nitriles

cosmo - 13-9-2011 at 17:31

I'm wondering if an equimolar amount of a different cyanide compound would substitute for potassium or sodium cyanide in the synthesis of carbonitriles via the use of the bisulfite adduct of a cyclic aliphatic ketone and a cyclic aliphatic amine.

Would compounds such as NH4CN, AgCN, Ca(CN)2, Zn(CN)2 and such work for this reaction?

Not really planning to actually do such a synth in the immediate future - just wanted to satisfy my curiosity.

Dr.Bob - 15-9-2011 at 13:29

Their solubility would be drastically different in solvents. NaCN and KCN are quite easy to work with (other than being toxic) - they are not too hygroscopic, cheap, somewhat soluble in some polar organics, and are easy to obtain pure.

I am not sure if NH4CN would even be stable, but the heavy metal salts are going to have good solubility, plus they will more likely to coordinate to themselves in complex aggregates. For example, ferrocyanides are not very toxic as the metal is bound so tightly to the iron. So they would not work in most cyanide reactions.

So I would think that zinc might form more complex salts which would keep it from reacting. This is not to say that they can't work, just that they are likely to have problems.

Bob