Sciencemadness Discussion Board

Make concetrated Sulfuric Acid

TheAMchemistry87 - 22-8-2012 at 09:19

So i want some conc. H2SO4 for some projects and im thinking if i can just heat heat NaHSO4 to release SO3 and dissolve it in water so is this a good project to make some conc. H2SO4?

-AMchemistry

Hexavalent - 22-8-2012 at 10:16

Heating sodium bisulfate will not yield sulfur trioxide.

Why not just purchase it as drain cleaner, or boil down some battery acid?

There have been numerous threads here before about sulfuric acid, UTFSE!

DJF90 - 22-8-2012 at 10:31

Quote: Originally posted by Hexavalent  
Heating sodium bisulfate will not yield sulfur trioxide.


You clearly did not see this: http://www.sciencemadness.org/talk/viewthread.php?tid=10217

Hexavalent - 22-8-2012 at 10:37

Quote: Originally posted by DJF90  

You clearly did not see this: http://www.sciencemadness.org/talk/viewthread.php?tid=10217


Well, I never knew that:)

Sorry for feeding bad information, my apologies.

Still, it probably isn't a viable method for making a useful supply of concentrated sulfuric acid in an amateur setting.

AJKOER - 22-8-2012 at 11:17

I believe a lower temperature is required for a workable decomposition of KHSO4 versus NaHSO4 into SO3. See "Fusion of Titanium Dioxide and Potassium Pyrosulfate" advice by Paul Gaines, Ph.D.

To quote: "Note that potassium disulfate begins to decompose around 300 °C and sulfur trioxide is evolved rapidly at 500 to 600 °C. "

Source: http://inorganicventures.com/tech/advice/sample-preparation/...

Please note SO3 is extremely dangerous (best avoided all together).

vmelkon - 23-8-2012 at 04:38

Ah crap! I am making FeSO4 just to decompose it and get some SO3. Wikipedia says it decomp around 480 °C

2 FeSO4 → Fe2O3 + SO2 + SO3

however, the link you gave says different. It turns in Fe2(SO4)3 first and that requires 700 °C to 950 °C. That is way too high for boro glassware.