Question Purify sulfuric acid

[bordello]

I want to purify my 50% sulfuric acid. I want to reduce the water. What should i do, simply boil it to 90-100 degrees Celsius ?

 

[WillD]

For what purpose do you need acid?

 

[bordello]

Sulfuric acid to produce Amphetamin Form Oil. Not for harmful reasons

 

[FENTAMAS]

Pour your 50% H2SO4 acid to the large borosilicate beaker (not more than half), wrap with aluminum foil and heat on electric hotplate till the volume reduced to the half of the initial size or white fumes become visible. You get around 75-80%. Temperature of the mixture will be over 200 *C
If you want 98% you should heat you 80% acid in round bottom flask at 350-400 C (outer temperature) to distill off all water. Use air condenser or just long tube. Don't use water cooling. Don't use vacuum.

 

[HHH]

Also use stiring so you can avoid bubbles that splash everywhere

 

[FENTAMAS]

Not all magnetic stir bars survive such harsh conditions, most of the cheap ones will demagnetize at temperatures as low as 180*C. Also not everyone have such powerful magnetic hot-plates that are capable to reach over 500*C, otherwise you will never reach inside temperature close to even 300*C.
I forgot to mention only about boiling chips from some crushed white ceramics that I used in the second stage.
For the first stage it's not necessary at all, moreover boiling will be only within first hour or less, later there will be just evaporation. (my setup was 3L beaker and 1.5kW cheap-as-shit hotplate with thermal relay)