Sciencemadness Discussion Board - Some experiments with cyanate ion

Some experiments with cyanate ion

woelen - 22-10-2021 at 10:00

The cyanate ion, OCN(-), is somewhat underrated on sciencemadness. The ion is only rarely mentioned and there hardly is experimental info on this ion. So, I decided to do some experiments and collected some interesting results in a single web page:

https://woelen.homescience.net/science/chem/exps/cyanate/ind...

If others of you have interesting ideas for experiments with cyanate salts, then please mention them here. If they are interesting and I have the suitable reagents, then I can extend this web page.

DraconicAcid - 22-10-2021 at 14:07

Neat!

The blue cobalt complex- with chloride or thiocyanate, I know this can be extracted into solvents such as butanol. Can this be done with the cyanato version?

The iron(III) reaction with cyanate- is this stable on standing? It looks like it's not so much a complex as the iron may be catalyzing the hydrolysis of cyanate to ammonia and hydrogen carbonate (which would give the rusty colour).

AvBaeyer - 22-10-2021 at 18:38

woelen,

A very nice presentation - love the colors. Sodium and potassium cyanates are used in organic chemistry. Under mildly acidic conditions cyanates will react with primary and secondary amines to form substituted ureas.

Also, remember the very famous Wohler experiment: ammonium cyanate conversion to urea, a foundational event in modern chemistry.

Keep up the great work.

AvB

walruslover69 - 23-10-2021 at 08:29

Do you have any insights into if the complexes are pure cyanates, or mixed aqua cyanates?

It would be cool to see some of them isolated as solids.

karlos³ - 23-10-2021 at 09:38

Quote: Originally posted by AvBaeyer

Sodium and potassium cyanates are used in organic chemistry. Under mildly acidic conditions cyanates will react with primary and secondary amines to form substituted ureas.

Hihihi thats funny because I also sit on such a thing.
Ultimately, its after oxazolidines/thiazolamines.

The paper I'm currently preparing to try is the attached one .
But starting from brominated phenethanolamine and 2-naphthylethanolamine, I think the thiazolamine in the former case is pretty interesting, pharmacologically, if yes, then the latter for sure too.
Brominated at the alcohol, that is.

Yes its obvious what I'm after, I know

(I would be happy about a few grams of thiocyanate for xmas by the way

)
But after all its experiments with cyanates too so I hope its ok for woelen.

[Edited on 23-10-2021 by karlos³]

Attachment: j.tetasy.2006.12.012.pdf (332kB)
This file has been downloaded 226 times

Linus1208 - 23-10-2021 at 11:40

Nice, I was just reading/thinking some interesting stuff about cyanates and similar, just what I needed

Bedlasky - 23-10-2021 at 18:02

Very nice experiment! I also wanted to try this experiment, but I am lazy (at least for know) to make some cyanate

. I every text book you find cyanate as example of ligand, you can find it in spectrophotochemical series, but no one write about complexes with cyanate. Really no one. I couldn't even found scientific paper on this. I read something about silver cyanate and Na, K cyanates, but that's all. So I am really glad that somone finally wrote something about it

.

Very nice photos and videos btw

.

You wrote that bonds between silver and nitrogen in silver cyanate aren't full bonds. What kind of bonds they are? Do you have some text about it? I found paper about structure of AgNCO and it says that Ag-N bonds are covalent.

Fulmen - 23-10-2021 at 23:55

Cyanates are used in nitrocarburizing.

Bedlasky - 24-10-2021 at 04:18

I think that slight yellow tinge of AgNCO is caused by presence of silver carbonate. Your cyanate certainly contains small amount of sodium carbonate. This can be nicely seen in the reaction between sodium cyanate and acid. After mixing relatively large amount of CO2 was released at once.

Mo(V) forms beautifuly colored complexes with halides and pseudohalides. You can make Mo(V) solution by reducing molybdate in HCl by some strong reducing agent like SnCl2, TiCl3, Na2S2O3 etc. Then add some NaOH until brown oxide starts to appear. Then redissolve it with small amount of acid and add sodium cyanate. Molybdenum in other oxidation states also form complexes with halides and pseudohalides, but they have mostly brown colour (except Mo(IV) complex in conc. HCl, which is red. I also made red fluoride complex, but I am not sure if this was Mo(V) or Mo(IV) complex).

I also read something about cyanide waste water procesing long time ago. Chlorine at pH 10 oxidize cyanide to cyanate (through ClCN intermediate). But this reaction can continue and cyanate is oxidized to CO2 and N2. You can try heat it in bleach, nitrogen should be released.

woelen - 24-10-2021 at 11:19

Quote:

The blue cobalt complex- with chloride or thiocyanate, I know this can be extracted into solvents such as butanol. Can this be done with the cyanato version?

The blue complex cannot be extracted into isoamyl alcohol (that is very similar to butanol, amyl alcohol and other similar solvents). I prepared a fairly concentrated deep blue solution for this experiment, with only NaOCN and CoSO4 in solution. I had 5 ml of this blue liquid. Next, I added 1.5 ml or so of isoamylalcohol and shook the liquid very vigorously for a minute or so. When put to rest again, the liquids quickly separate again. The isoamyl alcohol layer, which is on top, is colorless after separation. I tried three times, with different concentrations, and also after slight acidification, such that still no CO2 was produced. In all cases, the alcohol layer remained colorless.

Quote:

I think that slight yellow tinge of AgNCO is caused by presence of silver carbonate. Your cyanate certainly contains small amount of sodium carbonate.

This might be the case, but on quite some websites, this chemical is described as not being purely white, see e.g. https://www.oxfordlabchem.com/product-details.php?id=2465&am... but of course this is no guarantee that theirs is free of carbonate.

Bedlasky - 24-10-2021 at 16:52

Quote: Originally posted by woelen

Yes, you need just some moisture and cyanate hydrolyze in to carbonate and ammonia.

John paul III - 9-1-2022 at 03:19

Try oxidizing it to nitrate. there's supposedly a lot of catalysts that can do that, quote:

"About 3 hours heating [at 400 deg.] of KCNO in a well dried stream of air oxidizes it to KNO3, the oxidation is accelerated through catalysts such as metallic Cu, Ni, Ag, Au or their salts, as well as traces of moisture in the air stream, where KCNO is primarily split into easily oxidizable NH3 and K2CO3 (Ber. 59 [1926] 210)."

[Edited on 9-1-2022 by John paul III]

[Edited on 9-1-2022 by John paul III]

Bezaleel - 9-1-2022 at 18:04

Hi Woelen, is the cyanate solution alkaline or more or less neutral? If so, I'd be interested to see the colour of the manganese compound.

BTW, the picture of the Co solution with AgNO3 is added is really beautiful.

woelen - 9-1-2022 at 23:57

I'll try and see what pH the cyanate solution has. I can also add a solution of some MnSO4 to it. I'll come back on this.

woelen - 11-1-2022 at 01:45

I did the following experiment:
- Dissolve approximately 150 mg of NaOCN in 4 ml of distilled water.
- Using pH-paper, measure pH: This is between 8 and 9, according to the indicator paper I used.
- Dissolve 3 mg of NaBH4 in the solution of NaOCN. This is done to assure that on formation of a precipitate of Mn(2+) the dissolved oxygen in the solution does not cause formation of brown compounds. Mn(2+) is very prone to aerial oxidation at high pH.
- In a separate test tube, dissolve appr. 100 mg of MnSO4.H2O in 5 ml of distilled water. This gives a colorless solution (the color of aqueous Mn(2+) is too weak to observe it in this solution).
- Mix both solutions: No precipitate is formed, the solution remains perfectly clear and colorless. So, OCN(-) does not give a precipitate with Mn(2+). Probably a colorless complex is formed.
- Add a ml or so of 10% ammonia. A slimy off-white precipitate is formed, which on addition of more ammonia does not dissolve. This off-white precipitate most likely is hydrous Mn(OH)2. At the surface of the liquid, this precipitate slowly turns brown, despite the added NaBH4.