Copper oxychloride Cu2Cl(OH)3 preparation

[Powderman]

Today I made an attempt to synthesize sample of copper oxychloride from some chemicals I have at hand. I wanted it to be as easy as possible so I decided to try reacting solution of CuSO4 + KCl with solution of K2CO3. CO2 gas was forming as I was adding the carbonate so it seems the reaction went the correct path. Bluegreen precipitate formed. I have boiled a sample in test tube and it seemed to be stable. It was decanted with plenty of hot (60°C) water twice and filtered. Now it has to dry. Does anybody have experience with this? Any tips or useable knowledge?

[cmjlab]

I tried making some a while ago but had a problem with sodium contamination I believe. I think I ended up with a few different copper compounds, not just the oxychloride.

 

Have you tried a burn test yet?

 

I think I followed this process: https://www.sciencemadness.org/smwiki/index.php?title=Copper_oxychloride&oldid=13544#Synthesis

[Powderman]

I will try it as soon as it is dry. No sodium compounds were used so I hope for uncontaminated product.

[WSM]

I tried making some a while ago but had a problem with sodium contamination I believe. I think I ended up with a few different copper compounds, not just the oxychloride.

Have you tried a burn test yet?

I think I followed this process: https://www.sciencemadness.org/smwiki/index.php?title=Copper_oxychloride&oldid=13544#Synthesis

 

 

After reviewing the sciencemadness method, using several sodium compounds, I believe I understand the problem you encountered.

 

Powderman's method appears sound, and I expect much better results. Let us know how it tests.

 

WSM

[Powderman]

So I decided to record and show the result because I don´t know how it should look so I can not say if it is good or not. Lab grade KClO3 was used (my own might contain sodium contamination, it was made from flegmatized mix of NaCl and NaClO3, another recrystallization(s) are in plan). And I have substituted lactose for sucrose (don´t have lactose). Feel free to suggest another testing formula without lactose, red gum, parlon, shellac. PVC, phenolic resin, dextrin available. Would be dextrose a better replacement for lactose?

Formula used was 50AE lactose blue.

 

[cmjlab]

Pretty good looking blue. I've heard people point to copper oxychloride / KCL03 blue comps as some of the better bon-AP blues. I use Agten Blue, but may have to take another look at one of the oxychloride ones.

 

I don't think dextrose would work better than sucrose (sugar?), with lactose being a milk sugar. Hygroscopicity is one of the reasons plain sugar isn't used would be my guess, but again that looked pretty good.

[davidh]

Lactose is all about the flame temperature, and keeping it low.

[cmjlab]

Powderman - since your method was a success, I would like to try again myself, but I had a couple questions.

 

I understand the reasoning for the Potassium Carbonate (K2C03) soln. reacted with Copper (II) Sulfate (CuS04) soln., and potentially heat if necessary, to drive the displacement to completion.

 

1. How does the Potassium Chloride (KCl) contribute? What made you mix that with CuSO4 before the K2CO3?

 

2. When you boiled a sample of the Cu2(OH)3Cl did it pyrolize to CuO at all? Im curious if I overheat it, if it would begin to turn slightly brown as oxides form from pyrolysis of any carbonates and maybe the oxychloride.

 

Thanks!

[Powderman]

Standard procedure is to use CuCl2 + K2CO3 or KOH. But it is more convenient to use easy to obtain and cheap chemicals. CuSO4 contains no chloride ions, so KCl is added to provide it. NaCl works too but it could contaminate the product with sodium. I think NH4Cl should work too. The reaction just needs chloride ions in the solution. Adding HCl would also work, but the amount of K2CO3 would be higher to first neutralize the HCl and then react with CuSO4.

 

I made two small batches. Both worked. First closer to stoichiometric amounts and second with higher concentration of chloride ions (I think it should favor oxychloride creation over basic carbonate) and slight excess of K2CO3 because in the first batch the solution after precipitate settled remained slightly blue.

 

Boiling sample in test tube shows no CuO formation. Reaction alone was performed at room temperature by slowly adding carbonate solution to CuSO4+KCl solution while strong stirring. Slow addition also prevents overfoaming of escaping CO2 - big enough vessel shoul be used (min. 5x the volume of solutions). After the reaction is over and most CO2 escaped, decantation with hot water (cca 60°C) in even bigger vessel begins. Hot water changes the structure of the precipitate and speeds up settling down. I have repeated it 3x. Precipitate is filtered and dried.

 

My small batch:

 

CuSO4.5H2O 5g

KCl 1,5g

dissolved in 20ml H2O

filter out insoluble impurities if present

 

K2CO3 2,5g

dissolved in 7,5ml H2O

 

result:

CuCl(OH)3 2,1g

 

 

Image gallery from process

[cmjlab]

Thanks for the extra details. I don't doubt your method, I was just curious. I'll give it a shot later, I appreciate you sharing your method.

[Powderman]

Thanks for the extra details. I don't doubt your method, I was just curious. I'll give it a shot later, I appreciate you sharing your method.

 

It would be great if You or someone else would try it and share the results. I will make at least one bigger batch to have some on stock. Today my recrystallized chlorate dried, I hope for sodium free stuff this time...

[cmjlab]

I will give it a shot and share my results. I had to order some Potassium Chloride today though, I don't have any.

[Powderman]

Test with my recrystalized chlorate and the oxychloride I made:

[cmjlab]

Pretty good looking blue.

 

For the recrystallized chlorate, are you purifying commercial or homemade? I've wondered how much of a difference purified KCLO3 would make for blue comps. I have quite a bit of commercial KCL03 and I've been considering trying to purify that to test some comps.

 

I'm finished with my search for a "good blue" composition, and settled on Agten Blue. The only other curiosity I've had is purity (as mentioned above).

[Powderman]

I was able to buy flegmatized sodium chlorate (Na chlorate:NaCl mix 2:3). After extraction and reaction with KCl I was left with KClO3 in salt brine. First crystallization from it obviously resulted in contaminated product. Next recrystallization helped a lot but it still was not enough. So second recrystallization followed and I am not 100% sure if it is really pure now, but at least it works in blue comps. Maybe I will do one more and compare.

For recrystallization I have found that best amount of water is 2,5x the amount of KClO3. I use closed jar (900g ketchup glass bottle, 120g+300ml) in hot water bath, no leaks, spills, fumes... After all dissolves I let it cool in the bath. After it cools near room temperature I move it from the bath to cool outside (in winter) or into fridge. It can be cooled almost to zero for best recovery. Bottle with water for washing is also cooled together. It is vacuum filtered and washed once with cold water and once with IPA (not necessary, but it dries fast and the crystals are free flowing afterwards).

[cmjlab]

You read my mind! My next question would have been how much water you were using. In the past, I've just added boiling distilled water until everything was dissolved. I'd put that through a filter and then precipitate the crystals in fridge overnight. Then if really motivated, I'd boil down the remaining liquid and precipitate whatever else I could. I had not heard of using a IPA wash, or that it helped ensure free flowing crystals. I guess I always milled mine as soon as they were dry, but I do recall clumps from where they dried and stuck together. Good info, thanks - I'll try the measured water approach next time to see if my loss is reduced.