Sciencemadness Discussion Board

Purifying and containment of Sulfuric Acid?

Faal - 19-8-2007 at 20:33

I'm interested in purifying sulfuric acid. A source I have says you can take normal (car) battery acid and boil it to produce sulfuric acid, however, If I remember correctly, acids have a tendancy to 'bump' instead of gradually boil, which makes this very dangerous. IS there a "safe" way to purify sulfuric acid?

Also once purified, what should it be contained in? I assume Glass (since it dissolves plastic(?)) what kind of lid though would be best, since it can corrode metals so quickly (and plastic is obviously not an option)

woelen - 19-8-2007 at 23:16

You can fairly safely concentrate sulphuric acid, if you do this outside in a large glass beaker, with a shallow layer of liquid in it. The glass beaker should of course be real chemical glassware, which does not crack when it is heated.
You really need to do this outside, because thick very corrosvie white fumes are produced in the later stages of the boiling process. You can concentrate the acid to 85% or so with this method. Probably even better, but the last few percents of water are hard to remove and going well above 95% is not possible with this method (acid + water form an azeotrope).

Once the acid has cooled down, I would store it in the bottle in which you first had the car battery acid. You can use a glass bottle, with a thick plastic cap. The plastic cap is not eaten away that quickly, because the acid is not in constant contact with the cap. Sulphuric acid has a very low vapor pressure.

vulture - 20-8-2007 at 01:29

There are enough thread about this already. Search.