Sciencemadness Discussion Board

Copper Salicylate

nlegaux - 19-1-2015 at 13:41

I recently prepared some copper salicylate. Since there is nothing on the forum about it (the only sources I could find were Wikipedia and http://www.skylighter.com/fireworks/How-to-make-sky-rockets/...), I thought I should make it a thread.

To start, I created a solution containing 15g copper sulfate pentahydrate with a final volume of 75ml and a solution containing sodium salicylate with a final volume of 30ml. I then poured the copper sulfate solution into the sodium salicylate solution, which created a dark green tar-like precipitate. This was put onto an ice bath. Almost immediately small sky blue crystals started to form, and after about 20 minutes their growth had stopped. I broke up the crystals with a stir rod and vacuum filtered them. Although all of the sources I have been able to find claim copper salicylate is completely insoluble in water, the filtrate was a dark green solution. When I started to grind the dried copper salicylate down, I noticed that there were many small lumps of harder darker-green material full of voids. I believe this is the tar-like precipitate that initially formed (perhaps a different isomer?).

I think I will try to make an ammonia complex with it. Any other ideas on compounds to make with the filtrate and leftover copper salicylate? I will try to post pictures as soon as possible.

Thank you,

nlegaux

[Edited on 1-19-2015 by nlegaux]

DraconicAcid - 19-1-2015 at 13:47

It's possible that the tar-like material is a basic copper(II) salicylate; the dark green solution may be copper complexes. If you want to avoid stuff like that, I'd keep my solutions dilute, and possibly buffer with acetic acid.

[Edited on 19-1-2015 by DraconicAcid]

Oscilllator - 19-1-2015 at 17:07


There is something on the forum about it, in the aspirinate thread. I posted this:
Quote: Originally posted by Oscilllator  
This isn't stricly speaking an aspirinate synthesis, but I thought I'd post it here anyway.
Recently I successflly made a copper/salicylic acid complex from copper sulfate using the procedure that bfesser outlined, although I didn't bother to measure out the reagents.
It is interesting to note that although the aspirinate complex is insoluble, the salycilic acid complex is very soluble, having a deep green colour similar to a concentrated solution of nickel nitrate.
Here is a picture of the compound after vacuum filtration:

I also attempted to prepare a nickel analogue, however is seemed that only nickel carbonate formed :(

See the thread for a little more discussion on the topic:
http://www.sciencemadness.org/talk/viewthread.php?tid=9920&a...

nlegaux - 21-1-2015 at 16:49

Thanks for the link! Not sure how I missed that in the search. Is there a practical way to test if it is basic copper salicylate?

[Edited on 1-22-2015 by nlegaux]

Bert - 21-1-2015 at 20:30

I have made Copper benzoate, using Copper carbonate and benzoic acid in warm water. Went smoothly and easily, until I made the mistake of using the kitchen oven to dry the Copper benzoate precipitate... The whole place smelled like the way an old penny tastes, and the oven imparted a certain metallic taste to anything cooked in it for over a month!

If I were to attempt the salicylate, I'd likely try the same technique- Slowly adding Copper carbonate to a hot, well stirred solution of salicylic acid in distilled water, continuing addition of both reagents in proportion as off gassing of CO2 subsided, ending with just a slight excess to stoichiometric amount of Copper carbonate.

The suggestion to use Copper chloride and Sodium salicylate found @ Skylighter seems a poor choice if blue flames are the object- Any Sodium source is to be avoided when dealing with blue flame mixtures, very minor Na contamination seriously degrades a blue flame.

justdusty - 1-12-2017 at 11:14

I tried salicylic acid and copper carbonate it works but is very messy
Sodium salicylate and copper sulfate workers rather well
A 50 gram mix of each boiled mixed and allowed to cool naturally filtered off some beautiful crystals.

Bert - 1-12-2017 at 15:27

What caused the mess with salicylic acid/Copper carbonate? Have not yet tried this.

justdusty - 1-12-2017 at 23:39

Salicylic acid desolved in distilled water 200c reacts with copper carbonate with mucho much foam if added too fast

Bert - 2-12-2017 at 07:33

Quote:
Salicylic acid desolved in distilled water 200c reacts with copper carbonate with mucho much foam if added too fast


I don't think you did the reaction in water at 200 C, fix typo?

You can't just dump all the reagents in at once with either, also, when I did the benzoic acid version I used hot but NOT boiling water.

Should be the same ammount of off gassing per quantity of Copper carbonate used when making either the benzoate or salicylate.

If you have done both synthesis, was there any marked difference in the tendency to foam out of the reaction vessel? Did you have to proceed more slowly with either benzoic acid or salicylic acid?

Or did you just happen to make the salicylate first, and find out the hard way what happens when you dump all the carbonate at once into all the water and acid in too small of a pot?

Last time I made the benzoate I used a full pound of Copper carbonate and just a few grams less than the stoichometric quantity of benzoic acid in a full gallon of distilled water. I used a small enameled steel canning kettle, which had a volume of over 3 gallons to prevent foaming over, and I STILL had to add the chemicals a bit at a time, regulating the addition speed by watching for the foaming start to subside before adding the next increment.


[Edited on 2-12-2017 by Bert]

justdusty - 5-12-2017 at 13:44

Yes I did try Salicylic acid at about 200c to get it to desolve. was wrong only put 10 grams copper carbonate at a time I was wrong
You are correct copper benzoate reaction was not as strong as the salicylate reaction with copper carbonate but that was due to the heat

I've made copper benzoate no problems but some foaming

My copper salicylate is drying I will have to wash it again as it has some spots of black impuritys

Bert - 5-12-2017 at 18:14

I REALLY don't think you did the reaction at 200 C.


justdusty - 14-5-2018 at 12:27

wow long time since i checked this
you are probably right i should have used a thermometer this is where the temperature was set on the heat element which is 212 f not C

I have since tried boiling water with salicylic acid and adding copper nitrate letting it cool, it is crystallizing off now with beautiful turquoise crystals

DraconicAcid - 14-5-2018 at 13:08

*Adds copper salicylate to the list of things to make for the heck of it*

justdusty - 14-5-2018 at 13:16

has anyone tried to nitrate salicylic acid?

Bert - 14-5-2018 at 13:44

Yes, I have done this.

Several other members have posted on this as well.

I have also used both methyl salicylate and acetylsalicylic acid. Most choose aspirin as the starting material.




pikrinsaeure2.png - 4kB

[Edited on 5-14-2018 by Bert]

justdusty - 14-5-2018 at 15:12

very cool