Ancient production of sulfuric acid

[asca]

TL;DR Summary

Trying to find some detailed description, or even a video, that shows how the Old Persian managed to extract sulfuric acid from vitriol

Hi everydoby, the closest thread I found was this one, https://www.physicsforums.com/threads/production-of-sulfuric-acid.77077/, but I am not puzzled by and "missing oxygen". I'm trying to find a detailed description, or even better a video, where someone tries to replicate the process that we can assume ( I do not know if a trascript of the original description managed to get through time) was followed to make the first sulfuric acid in history. Not only the production, but also the " original testing" would be interesting to show in a classroom lesson. Thank you for any help you may be able to provide.

 

[TeethWhitener]

I don’t know about a video (you can use google just as well as I can), but the process is straightforward.

1) Put copper sulfate into a distillation apparatus (the alchemists used a crude apparatus called a retort—sometimes also called an alembic).
2) Put the neck of the retort into a vessel of water (better yet, put the opening of the neck into the water so that the distillate must bubble through the water).
3) Then just heat the dickens out of the copper sulfate.

Heating gives you gaseous sulfur trioxide which, upon reaction with water, gives sulfuric acid.

 

[DrStupid]

2) Put the neck of the retort into a vessel of water (better yet, put the opening of the neck into the water so that the distillate must bubble through the water).

It works better with sulfuric acid (96-99%) instead of pure water.

 

[TeethWhitener]

It works better with sulfuric acid (96-99%) instead of pure water.

Yes, when making sulfuric acid, it helps to start with sulfuric acid.

(Note to OP—this isn’t as mindless as it sounds. In fact, it’s how sulfuric acid is made industrially today. Sulfur trioxide is made by roasting sulfur in air. Dissolving $SO_3$ in sulfuric acid produces oleum, which is then diluted to form sulfuric acid. It ends up being less energy intensive—and more cost-effective—to do it this way than to dissolve $SO_3$ directly in water and distill the water up to concentrated sulfuric acid strength.)

 

[Borek]

Sulfur trioxide is made by roasting sulfur in air.

Not exactly - burning sulfur produces SO₂, to oxidize it further you need a catalyst.

 

[DrStupid]

to oxidize it further you need a catalyst

or a suitable oxydizer like NO₂

 

[asca]

OK. Thank you everybody. As I said I'd like to recreate a production process BEFORE sulfuric acid was known, so TheethWithere gave me a good clue. Now the second part of my initial question. How is it reasonable to show a way to test it, once again BEFORE litmus paper was available. Thank you again

 

[TeethWhitener]

How is it reasonable to show a way to test it,

This would depend on what you want to know. How would you test it?

 

[Borek]

Note: plenty of natural indicators that change their color depending on pH (not that litmus is unnatural in any way). Red cabbage juice comes to mind as a first trivial example.

 

[asca]

Well my idea is to show them how stronger such acid is, I mean the one we make in the classroom using the ancient method, with respect to vinegar. Before "making" H2S04 I may show then the effect of vinegar on baking soda, now I do not know if the H2S04 made in the classroom can "boil out" some zinc for example.

 

[Borek]

I strongly doubt you can make an acid strong enough given time and safety limitations.