Sciencemadness Discussion Board - Freeze concentrating acids

Freeze concentrating acids

symboom - 23-4-2018 at 19:25

Acording to the freezing curve of sulfuric acid
Water can freeze out of the mixture all the way up till 60 percent wich would be useful when the sulfuric acid comes from. Copper sulfate and if grafite is used the particles filtered through copper wool.

Same with acetic acid but i think higher is achievable

I cant find any information on this

Not sure if phosphoric acid
Nitric and hydrochloric acid can be freeze concentrated

weilawei - 23-4-2018 at 19:42

From my lab notebook:

Quote:

1 gal. of 5% w/v distilled white vinegar was placed in a freezer at ~-13.2°C for approx. 19 hours until it separated into a water-rich frozen portion and an acetic acid-rich liquid portion. The liquid was decanted off and collected (~550mL). 5mL of the acid was titrated with a 0.848 M soln. of NaOH, and it was found to be 2.4M / 14.3%.

I didn't continue further because this was my stripping run before producing anhydrous sodium acetate, which was later reacted with sulfuric acid and distilled to produce glacial acetic acid.

A little bit of tangentially related crystal porn:

Sodium acetate trihydrate

Recrystallization

Filtered and ready for the oven

GAA still (The 1L flask was waay too large and swapped for a much smaller receiver.)

[Edited on 24-4-2018 by weilawei]