05-14-03 23:02
No 433187
"The first method involves reacting cyclohexanone with the hydrochloride salt of piperidine and aqueous NaCN or KCN."
Is it possible to substitute CuCN or AgCN in the PCP synthesis, or would the copper molecule interfere with the reaction?
If the copper is problematic, is it feasible to convert the CuCN to Na or KCN?
(Hive Bee)
05-15-03 00:06
No 433200
The problem with cuprious cyanide is it extremely low solubility. I doubt it would work with the copper version.
A hazardous way of turning cuprious cyanide into potassium / sodium cyanide is dripping conc. sulfuric acid over the compound and leading the gas through some NaOH. This is as dangerous as it gets in the field of recreational chemistry, so think twice about doing it!
Regards
Bandil
Cops are not there to help you, they're there to bust you.
(Stranger / Eraser)
05-15-03 05:28
No 433245
Thanks Bandil, I hadn't even considered solubility issues in the substitution.
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"Piperidine, 85 g (99 ml, 1 mole) is carefully mixed with 84 ml of conc. HCl and 200 g of ice-water, and the pH is adjusted to 3-4. To this solution, 98 g (104 ml, 1 mole) of cyclohexanone is added, followed by 68 g (1.0 mole) of KCN in 150 ml of H2O (or 116 ml of 40% aqueous NaCN) without external cooling but with efficient stirring."
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A quick test would tell is the CuCN dissolves, and I think it may, in the presence of such high molarity HCl. HCN in situu?
For some reason I think, solubility issues aside, that the reaction mechanism may be different, with Cu possibly forming some sort of complex in the process. Could well be wrong actually.
Thanks for the tip on HCN generation! I thought that might be a possiblity, prolly, the only way.. And yes, the production of HCN with sulfuric is something I would choose to avoid at an cost. It's not something to play with without strict laboratory protocol and equipment IMHO.
(Hive Addict)
05-15-03 10:04
No 433278
why wouldn't you want to use the enamine route? tosic acid
is very easy to synthesise and a dean-stark is easily improvised.
Post 389646 (Antoncho: "Toluenesulfonic acid - tips and tricks.", Methods Discourse)
(HyperLab Bee)
05-15-03 10:18
No 433280
Acetonecyanhydrine (1 mol) + solution of 1 mol of NaOH (or KOH) in minimal amount of water__> two layers: upper- acetone is discarded, bottom - water solution of NaCN (KCN). Easy and safety.
(Stranger / Eraser)
05-15-03 10:57
No 433291
In this case, the PTSA route is by far the easiest and most attainable, absolutley agreed. The dean stark trap as shown in the Equip section is fine, and a variety of other ways suggest itself. Like a modified shortpath without water cooling and then a condensor over a RBF attached to it.
also the KOH dried synth of PCE is simplicity as well, thouhg I think the dimethyl method looks more promising.
I guess I just am curious about the copper and it's effects in the reaction more than anything else.
I am asking on more purely academic grounds.
Thanks for the Acetonecyanhydrine info, but unfortunately, availability is an issue here.
(Stranger / Eraser)
05-18-03 03:17
No 433808
One last bump... To the top, before I abandon this.
Anyone, speculations? Anything? Or is this an impossible question?
(PVC-Analog Taste-Tester)
05-18-03 07:30
No 433846
Maybe calcium cyanide could be used? It's probably easier to get than K or Na-cyanide, but I don't know its solubility.
..Here we go; the Merck says "Commercial prepns contain 40-50% Ca(CN)2.", so we know it's soluble enough to use in the reaction you speak of. Why wouldn't it work?
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