Sciencemadness Discussion Board

Sodium Ibuprofenate

Chemistry_Keegan - 16-4-2014 at 18:04

So quite a while ago I had an old tablet of ibuprofen lying around in a cupboard. If I recall correctly, the pill looked like this:



Aware of the fact that ibuprofen is an acid, I decided to try mixing it with a solution of sodium bicarbonate. I wasn't expecting there to be a reaction because of how weak sodium bicarbonate is as a base, but to my surprise, something definitely happened.

When I first dropped the pill into the solution, no reaction was immediately visible. However, not long after that, I began to observe some bubbling on the surface of the pill. Once it started, it didn't take long for the bubbling to get rather violent. After leaving the room for several minutes, I came back to find a pile of white powder at the bottom of the container, which now contained a clear solution with the orange coating from the pill floating on top. I predict that this reaction occurred:

NaHCO3 + C13H18O2 → NaC13H17O2 + H2O + CO2

Can I get any confirmation on this? If this reaction did occur, would the sodium ibuprofenate be soluble, or be contained in the white powder? I tried researching sodium ibuprofenate, but I've only seen it mentioned once on some french chemistry quiz that I found. There is a bit information about copper ibuprofenate on this page, but it's the only ibuprofenate salt I could find at least a bit of information on. Have any of you ever experimented with these before?

And by the way, I'm aware of the fact that some of you may not like it when these salts are referred to as ibuprofenates, but it's much easier to type than the full name:P Also, here is the link to the french quiz I mentioned earlier for anyone who can speak the language and is interested.

[Edited on 17-4-2014 by Chemistry_Keegan]

12AX7 - 16-4-2014 at 18:20

The free acid is going to have low solubility in water (I don't know how much offhand), but the salt will be pretty soluble. Compare, for instance, oil on water (immiscible) versus soap (which doesn't really dissolve all that fast in and of itself -- it also disperses as an emulsion rather than free molecules -- but it still dissolves, in a manner).

The white powder might be unreacted stuff (not enough soda?), or fillers and binders (if you have the bottle still... does the label say what and how much?).

Tim

DraconicAcid - 16-4-2014 at 20:04

Ibuprofen is a more-or-less plain carboxylic acid (a substituted phenylpropanoic acid), and will have a Ka of about 10^-5 (just like acetic and other carboxylic acids). So hydrogen carbonate (Kb about 10^-7) is plenty basic enough to deprotonate it.

unionised - 17-4-2014 at 09:57

Some tablets are coated so they release the drug slowly. If that coating dissolved in the bicarbonate solution then you would get a sudden increase in reaction.

sasan - 13-5-2014 at 22:45


Beside the ibuprofen,react mefenamic acid or penicilin G with soda to obtain the these salts too.recently I make it by opening the mefenamic acid capsules and dissolving it in sodium hydroxide solution,it has very beautiful little crystals

blogfast25 - 14-5-2014 at 05:08

Quote: Originally posted by Chemistry_Keegan  
I predict that this reaction occurred:

NaHCO3 + C13H18O2 → NaC13H17O2 + H2O + CO2



Well, did you observe any CO2? If you reacted significant quantities at least some bubbles should be apparent, even though they might be slow in coming forth.

sasan - 15-5-2014 at 23:08

For certainty I react my sodium mefenamate solution with Cu(NO3)2 solution to see what would happen.now there is a dark greenish yellow precipitate that I think it should be copper(l)mefenamate.Maybe mefenamate ion reduced the copper 2+ ion to the 1+ ion because of color changing.imediatedly after combination of these two solutions,the solution got a deep blue color after that it got turbid and dark green color.after that a yellowish green precipitate slowly settled bottom of beaker
blogfast25 It shows that there is no carbonate or hydroxide ion in solution(comparing to the copper hydroxide and hydroxy carbonate precipitate color)

The Volatile Chemist - 16-5-2014 at 11:48

Quote: Originally posted by sasan  
For certainty I react my sodium mefenamate solution with Cu(NO3)2 solution to see what would happen.now there is a dark greenish yellow precipitate that I think it should be copper(l)mefenamate.Maybe mefenamate ion reduced the copper 2+ ion to the 1+ ion because of color changing.imediatedly after combination of these two solutions,the solution got a deep blue color after that it got turbid and dark green color.after that a yellowish green precipitate slowly settled bottom of beaker
blogfast25 It shows that there is no carbonate or hydroxide ion in solution(comparing to the copper hydroxide and hydroxy carbonate precipitate color)


This sounds more like a complex than a simple Ionic bonding (Which, thanks to the crew here, I've been beginning to understand; are you familiar with chemical complexes?).
In doing some Google searches, it seems that both mefenamate and ibuprofenate complex with common metals, and I assume copper complexed with one or both of these, possibly water too (deep blue color). I doubt copper was reduced, complexes of copper can bring out rapid color changes. Are you sure the precipitate isn't a carbonate of a complex?

blogfast25 - 16-5-2014 at 14:39

Quote: Originally posted by sasan  
For certainty I react my sodium mefenamate solution with Cu(NO3)2 solution to see what would happen.now there is a dark greenish yellow precipitate that I think it should be copper(l)mefenamate.Maybe mefenamate ion reduced the copper 2+ ion to the 1+ ion because of color changing.imediatedly after combination of these two solutions,the solution got a deep blue color after that it got turbid and dark green color.after that a yellowish green precipitate slowly settled bottom of beaker
blogfast25 It shows that there is no carbonate or hydroxide ion in solution(comparing to the copper hydroxide and hydroxy carbonate precipitate color)


You make a lot of claims here (and drag me into it for some reason) but present precious little evidence for them.

What was the pH of your 'sodium mefenamate' solution? Being the salt of a weak acid, it must be definition quite alkaline. Unless the alleged 'copper mefenamate' is much more insoluble than Cu(OH)2, it's the latter you will precipitate, NOT 'copper mefenamate'.

If we (reasonably) assume the pKa of mefanamic acid to be similar to that of the related benzoic acid, then the pH of a 1 M 'sodium mefenamate' solution would be about 11.5. Fairly alkaline.

Did you isolate 'sodium mefenamate' as crystals? If so, how?

What happens if you subject the alleged 'copper mefenamate' to a strong acid like HCl or H2SO4?

For any reduction to have taken place, an oxidation must also have taken place. Which oxidation have you observed?


[Edited on 17-5-2014 by blogfast25]

sasan - 17-5-2014 at 23:12

Mefenamic is insoluble in water,I opened some mefenamic acid capsules and pour them to water,added sodium hydroxide in very small portions till all mefenamic acid dissolved.so there was a solution of sodium mefenamate,the solution was hot because of hydroxide dissolving,after colling there was some little crystals maybe sodium mefenamate
I didnt know the ph but I thought it was alkaline(sodium hydroxide strong base and mefenamic is not strong acid)
I stated that "MAYBE" THERE WAS A REDUCTION FOR COPPER IONS and I was not sure
Beside these,I treat sodium mefenamate with cobalt salt in solution faze,there was light blue precipitate,after some hours the precipitate was colorless with a light torquise blue tint
blogfast25 you are right,I'm not sure if there is copper mefenamate or not,But i'm sure I made sodium mefenamate solution
sorry for bad english language

blogfast25 - 18-5-2014 at 06:52

Test your 'copper mefenamate' but treating it with strong HCl or 50 % H2SO4. Because mefenamatic acid is weak, it will be displaced by the HCl/H2SO4 and should reappear as a white insoluble material. If on the other hand your product is a form of copper hydroxide, it will simply dissolve completely.