Sciencemadness Discussion Board

Separation of CuSO4 and H2SO4

thissideup - 26-9-2007 at 10:47

http://www.novacan.biz-web.ca/msds/msdscp.htm
http://www.novacan.biz-web.ca/msds/msdsbp.htm
I have this lying around from an old project and I'm trying to get the CuSO4 to crystallize in the first product, as for the second product I'm trying to isolate the HNO3. I'm having trouble understanding the % (w/w) of the MSDS, does that mean the rest is H2O? do I simply get it to sublimate?

Cu2O+2HNO3--->Cu(NO3)2+Cu+H2O
Is to be the end result of the experiment I would like to perform

edit: not asking for spoon feeding, just having a little trouble with the stoichiometry.

[Edited on 26-9-2007 by thissideup]

Antwain - 26-9-2007 at 11:54

After looking at those data sheets, I still have no idea what you did...

I cant see where you are getting Cu(I) from.

Nitric acid will react with copper metal.

If you just mixed those things together, you would probably need to boil it to get CuSO4 to crystalise, and in doing so will probably lose a good portion of your nitric acid - if you are not using a refluxing condenser.

Edit- right I think i see. You intend to add Cu2O to the nitric acid made. I can't see you easily making nitric acid from that stuff without a condenser. Also, the reaction you propose will not happen:
F.Sherwood Taylor, regarding Cu2O-
"Nitric acid reacts violently with it giving cupric nitrate and oxides of nitrogen"

[Edited on 27-9-2007 by Antwain]

thissideup - 26-9-2007 at 12:03

oh! no no I have not yet done any thing I just need to get the sulphuric acid out of the copper patina. and the nitric acid out of the lead patina. the equation is simply the reaction I will accomplish when I have those two products. I did just drop some iron wool in a small amount for kicks and It coated it pretty fast with copper so I'm thinking there is just copper dissolved in the acid with distilled water in it. So now all I need help with the isolation of HNO3 from a solution of Se20 and CuSO4. I'm assuming the Se2O is a solid, if I'm wrong correct me please.


Edit: ha ha "SeO2" not "Se2o". Why will it not work? The math seems okay. Cu(NO3)2+Cu+H2O seems to be balanced... hmmm. How about removing the SeO2 from the lead patina, then I will have a solution I can work with.


[Edited on 26-9-2007 by thissideup]

[Edited on 26-9-2007 by thissideup]

woelen - 26-9-2007 at 13:06

Cu2O reacts with non-coordinating and non-oxidizing acids as follows:

Cu2O + 2H(+) --> Cu(2+) + H2O + Cu

This works nicely. I did this experiment with dilute H2SO4, and with dilute HNO3 it will work as well. With strongly oxidizing acids, the copper(I) in Cu2O will be oxidized to copper(II). So, with concentrated HNO3 this will not work. Then you'll get copper(II) and nitrogen oxides.

With HCl this also does not work. The chloride in HCl forms a complex. The reaction then will be as follows:

Cu2O + 2H(+) + 4Cl(-) ---> 2CuCl2(-) + H2O

The CuCl2(-) complex ion quickly is oxidized by oxygen from air, leading to dark brown/black mixed oxidation state complexes of copper (I) and copper(II).


Isolating the copper sulfate from the acid could be done by heating the liquid and driving off most of the water. Copper(II) sulfate will crystallize, but it also still will contain quite a lot of acid. With recrystallization from water, you could remove most of the acid.

Isolating the nitric acid from the second product can only be done by distilling this liquid. First, mainly water is driven off. After the product is concentrated more strongly, nitric acid may distill, but most likely also some of the selenium may distill over as a slightly volatile compound.

contrived - 26-9-2007 at 13:37

I still don't get what you're trying to end up with. I assume you want the, metals, metal salts or the acids by themselves. Which?

@Woelen: could he throw in NH4(X) and get the ammonia complexes? and if so would they preciptate?

CuSO4 is cheap and available isn't it? One of the other TA's (lower Miocene times) was making a CuSO4 crystal in her bathtub and it was starting to cost a lot .. bringing in drums of the stuff. Nowadays she'd have the enviro-cops all over her building.

not_important - 26-9-2007 at 16:58

Quote:
Originally posted by thissideup
http://www.novacan.biz-web.ca/msds/msdscp.htm
http://www.novacan.biz-web.ca/msds/msdsbp.htm
I have this lying around from an old project and I'm trying to get the CuSO4 to crystallize in the first product, as for the second product I'm trying to isolate the HNO3. I'm having trouble understanding the % (w/w) of the MSDS, does that mean the rest is H2O?

Yes, remainder is water.
Quote:
do I simply get it to sublimate?


Uh, sublimate what? Nothing is those products sublimates.
Quote:
Cu2O+2HNO3--->Cu(NO3)2+Cu+H2O

Doesn't happen. You will get Cu(NO3)2 but no copper metal, and it will generate nitrogen oxides. Stoichiometry is messy, depends on concentrations and temperatures.


For the H2SO4 + CuSO4 I think the best bet is boiling it down until CuSO4 crystals start to form, then cooling it and separating the solid copper sulfate. To avoid getting sulfuric acid mist all over, you might want to do this in a distilling rig, include a mist trap and/or a short fractionating column.

Some copper sulfate will be left in the sulfuric acid+water, then only way to get clean sulfuric acid is to distill it out of the mix. Once again, mist trap and short column. Don't distill to dryness, and note that it is likely to bump when solid CuSO4 starts to form again.

As for the second product, the SeO2 is in solution, partially as SeHSO3. Distilling off the HNO3 under reduced pressure would be the first step. As it forms a high boiling azeotrope, water will distill over first. Once again do not toake it to dryness.

After that the selenium can be separated by adding water to get everything back into solution. After that treating the solution with SO2 will precipitate elemental Se and/or CuSe, which can be removed by filtration leaving a solution of CuSO4.

thissideup - 26-9-2007 at 18:56

Is there a way that I could react the selenium dioxide with the nitric?

[Edited on 7-10-2007 by thissideup]

thissideup - 7-10-2007 at 10:03

I'm gonna bump this for response cause it will never happen otherwise and I don't want to make a new thread on this topic

froot - 8-10-2007 at 06:42

With such little sulfuric acid in the solution, would it not be worth using the rest of the acid to produce more copper sulfate? Then it would be a case of evapourating the water off and be left with pure copper sulfate not so?

not_important - 8-10-2007 at 07:26

Quote:
Originally posted by thissideup
Is there a way that I could react the selenium dioxide with the nitric?


And do/get what?

Nitric acid will not oxidise SeO2 further, chloric acid or fused KNO3 will do the job.