Gary - 9-12-2010 at 02:39
Hi,
Has anyone had any success using drain cleaner grade sulphuric acid in their chemistry syntheses? Specifically, I am referring to the 'One Shot'
brand, 91% concn.
The downside is that it contains contaminants- a red dye and inhibitors. Would these contaminants negatively affect chemical reactions and, if so, how
would they best be removed without having to resort to distillation? Would activated carbon, with its high surface area, adsorb the dye, effectively
removing it from the acid?
Considering that the dye is an organic compound, and that hot conc. sulphuric is strongly oxidising, would heating the acid for a prolonged period
over a hotplate oxidize the dye to carbon (which, I assume, could be easily removed by Buchner filtration through a sintered glass frit) or carbon
dioxide gas (which simply bubbles out of solution)?
ScienceSquirrel - 9-12-2010 at 03:45
I have used this to make ferrous sulphate, ferric ammonium sulphate (iron alum) and other things.
The products look perfectly normal and the melting point for the iron alum was spot on the literature.
Preparation of Ammonium Iron (III) Sulphate (Ferric Alum)
Experimental
Ferrous sulphate heptahydrate (11.1g, 40mM) was weighed into a 50ml flask. Deionised water (10mL) was added and the mixture was stirred magnetically
with gentle warming until the salt had dissolved. Sulphuric acid (90%, 1.8mL, 30mM) was added dropwise and the mixture was placed in a water bath.
Hydrogen peroxide (35%, 2.9mL, 30mM) was added dropwise to the stirred mixture. The reaction is vigorous and the reaction mixture goes a muddy brown,
clearing to a bright orange as it nears completion.
After the addition the water bath was removed and the mixture was heated for 5 - 10 minutes until effervescence ceased. A solution of ammonium
sulphate (2.6g, 20mM) in deionised water (5mL) was added in one portion and the mixture was filtered. The filter paper was washed with deionised water
(5mL) and the solution was cooled in an ice salt bath. Pale lilac crystals gradually formed from the deep brown solution. The crystals were filtered
off, pressed dry and then allowed to dry in the air. The solid is a pale amethyst in the mass but colourless as small. single crystals. Yield 12.7g,
66%. mp 39-40.5C, Sigma Aldrich catalogue 37-41C.
1281371269 - 9-12-2010 at 14:04
You can decolourise it by adding a small amount of Conc. H2O2 and leaving it for a while, then heating it to drive off the water. This will oxidise
out a large number of the impurities but plenty will stay.
I've also just found this: http://www.whitedogbikes.com/item--Battery-Acid-Electrolyte-...
That would be relatively pure, you would just need to boil it down.
BlazeBall - 10-12-2010 at 15:46
Abbey chemicals sell 98% sulphuric.
http://www.abbey-chemicals.co.uk/index.php?main_page=product...
Reagent sells AR grade sulpuhric acid.
http://www.reagent.co.uk/sulphuric-acid-ar/sulphuric-acid-ar...
[Edited on 10-12-2010 by BlazeBall]
cnidocyte - 10-12-2010 at 16:26
In Ireland you can get 98%. In general, anything you can get in Ireland, you can get in the UK.