Sciencemadness Discussion Board - Did I accidentally Make Copper Acetate?

Did I accidentally Make Copper Acetate?

Noflers - 18-3-2016 at 12:56

I have a bunch of copper wire I cut up in order to remove sulfur compounds from organic solutions. The copper ends up getting fouled up and I just soak it in Venegar to clean. Well, last time I did this I forgot about it so the copper has been soaking in the vinegar for about a week and a half. I found it after aabout three days and realized what I did. The copper was heavily oxidized so I started to give it a swirl every other day to dissolve the oxides. now I have a very attractive blue solution in the jar. I took the photo after I swirled so the nice little crystals aren't visible, but they do form.

Is that copper acetate? Should I filter out the solids and try and make more crystals?

aga - 18-3-2016 at 13:05

Yep.

You made copper acetate.

Nice crystals !

I got some Zinc acetate on the go right now.

[Edited on 18-3-2016 by aga]

Noflers - 18-3-2016 at 13:21

Do you think a coffee filter will be sufficient? Ha, I don't have much else at the moment.

aga - 18-3-2016 at 13:38

Yep. Coffee filters are pretty good.

If you want some nice crystals, pour off as much of the vinegar as you can (without losing any crystals) then add the minimum amount of hot water needed to dissolve those blue crystals. You will need to stir/swirl the stuff.

Have some patience with this or it will take longer in the end.

Then filter through a coffee filter. Use two filters if they do not look so good.

The liquid should be pretty much saturated, so nice clean crystals will form later, maybe immediately, maybe overnight (i do not know).

If they do not (too much water added) just boil off some water, leave it to cool and see what happens.

If you get impatient, stick it in the fridge with some cling film to seal it, ( to protect the food!) although the crystals will not be so good.

For really pure crystals(99.9%?) repeat the dissolve/let crystals form steps twice more.

They call this 'Purification by Recrystallisation'.

Edit:

Fothot to mention: when the crystals form enough you must pour off the liquid above (aka the 'supernatant') to get an increase in purity. This loses quite a lot, but the crystals are purer.

Further edit:

Please put any stuff like this where you're not following any published process in Beginnings. You'll get more helpful answers.

[Edited on 18-3-2016 by aga]

woelen - 18-3-2016 at 14:45

It is best not to use pure water, but water with a little acetic acid (vinegar without added spices and coloring agent also is OK) in it. Acetate is the conjugate base of a weak acid and salts of this easily hydrolyse with formation of acetic acid and basic compounds.

Pure water leads to hydrolysis and then you get basic acetates or even some copper hydroxide, which makes the liquid cloudy and leads to impurities.

aga - 18-3-2016 at 15:01

Wow ! Pure water being Bad is a new one for me.

Thanks woelen.

Listen to the wise words Noflers, i certainly will.

Noflers - 18-3-2016 at 15:12

Well, I jumped the gun and added pure water, but only a small amount. (just enough to rinse the filter)

Apparently, what I assume to be copper (copper/bronze in color), made it through the filter and is settling on the bottom of the beaker (Slowly).

The layer of acetic acid on top appears to only be turbid due to the fine bronze colored particulate.

gsd - 18-3-2016 at 23:18

@Noflers

Keep it in mind that CuAc2.H2O is sparingly soluble in water. IIRC the saturated solution at RT is about 6%. After filtration, you need to evaporate considerable amount of water in order to get small crop of crystals.

gsd

Noflers - 19-3-2016 at 10:23

The solution is pretty clear, I'm going to evaporate the water as soon as I siphon off the solution.

Camroc37 - 19-3-2016 at 12:29

Quote: Originally posted by Noflers

I have a bunch of copper wire I cut up in order to remove sulfur compounds from organic solutions. The copper ends up getting fouled up and I just soak it in Venegar to clean. Well, last time I did this I forgot about it so the copper has been soaking in the vinegar for about a week and a half. I found it after aabout three days and realized what I did. The copper was heavily oxidized so I started to give it a swirl every other day to dissolve the oxides. now I have a very attractive blue solution in the jar. I took the photo after I swirled so the nice little crystals aren't visible, but they do form.

Is that copper acetate? Should I filter out the solids and try and make more crystals?
Definitely make more if you want. If you purposely make it though, add some H2O2 or another oxidizer to speed up the reaction.

aga - 19-3-2016 at 12:39

Looks like you edited a quote tag there Camroc37.

Noflers - 19-3-2016 at 13:31

Quote: Originally posted by aga

Looks like you edited a quote tag there Camroc37.

Lol, looks like you're supposed to be the drunkard, not him.

aga - 19-3-2016 at 14:49

Quote: Originally posted by Noflers

Lol, looks like you're supposed to be the drunkard, not him.

Easy mistake to make. Done it myself a few times. Easily fixed too.

If 'e's lookin to take de toitle i'll feight 'im fer it.

If 'e wins, well, maybe chuck in a coupla dags loike.

[Edited on 19-3-2016 by aga]