Sciencemadness Discussion Board

making H2SO4?

Brominerain - 4-7-2022 at 07:10

I want to make sulfuric acid. At first, I thought that it would be a good idea to thermally decompose CuSO4 (which yields CuO + SO3) and then pass the gas through water to make the H2SO4. however, I was concerned about the SO3 escaping (even though I have a respirator, it seems scary to have SO3 around)
So I tried to find another way to produce it. One thought was to use oxalic acid and calcium sulfate to make it.
(HO2C-CO2H + CaSO4 => H2SO4 + CaC2O4)
As I am uncertain if the reaction happens to begin with or if the product will be of good quality, I certainly need help.
(I need the H2SO4 to make HNO3)

[Edited on 4-7-2022 by Brominerain]

[Edited on 4-7-2022 by Brominerain]

Triflic Acid - 4-7-2022 at 10:19

Distill battery acid, is much better than killing everyone around you with a fume of H2SO4 from an SO3 setup. One important thing to think about when doing this stuff is that if you need to wear a gas mask, so do your neighbors. So if you live in a densely populated its not a good idea to do stuff like this. Second, do your research before attempting something like this. Adding SO3 directly to water is a great way to kill people, but not to make H2SO4. To make H2SO4 from SO3 you need to first react the SO3 with concentrated sulfuric acid to get H2S2O7, aka oleum. This can then be slowly diluted with water to get conc. H2SO4. Adding SO3 to water will create enough heat to boil the H2SO4 produced, creating a extremely dangerous cloud of acid vapor. Also, why not use Sodium Bisulfate? Works the same for making HNO3.

Rainwater - 4-7-2022 at 11:33

Electrolysis of copper sulfate with a carbon anode is a very easy method. For all practical purposes, a better anode is needed for larger quantities but for really small scale a pencil will work

2 CuSO4 + 2 H2O = 2H2SO4 + 2Cu + O2
I recommend a current-controlled power supply but in a pinch, a 6v battery and 20-ohm resistor can be used. If a resistor is not available then another pencil can be used to draw a thick line on a piece of paper. The thicker the line, the less resistants it has

j_sum1 - 5-7-2022 at 00:12

Brominerain, there is a sticky on this topic and also a wiki page (I think).
A lot depends on what resources you have available and what quantity is required. I myself used to have good success in electrolysis of copper sulfate using a lead anode.

Rather than beginning a new topic I am going to recommend searching on this site. There is a lot of good information here slready.