Sciencemadness Discussion Board

HCl purity

B(a)P - 25-1-2020 at 02:07

This is mostly for people residing in Australia. Previously I had used ar grade HCl in my experiments. Recently I decided to use 'digers' brand HCl to make acetone preoxide.
When I added the digers HCl to the chilled acetone preoxide mix it turned orange.
Anyone else had a similar experience or issues with digers conc HCl? The yield still seems fine, but I am yet to test the product. I will report back when I do.

j_sum1 - 25-1-2020 at 02:18

There is HCl available at the moment (two brands at least) that seems to be contaminated with titanium.
If you react with Mg or Zn you get a purple solution containing TiCl3 which is slightly cloudy from TiO2 that forms.
If you add peroxide you get the deep amber titanium peroxide complex.
Previous mention of the problem.

What are you making acetone peroxide for anyway? No don't answer that. Suffice to say it is not recommended.

[Edited on 25-1-2020 by j_sum1]

B(a)P - 25-1-2020 at 02:26

AP happens to be the cheapest/ easiest primary I can produce to DDT a secondary suitable for my needs.
I am currently researching the best destruction option for a particular cbrn agent for a new project my company has kicked off.

B(a)P - 25-1-2020 at 02:43

Which brands?

j_sum1 - 25-1-2020 at 03:00

Quote: Originally posted by B(a)P  
Which brands?

Bondall and Diggers.

Here is Tdep having the same issue.
Watch to at least the five minute mark.

I made a comment which you can probably find if you scroll for it.

[Edited on 25-1-2020 by j_sum1]

B(a)P - 25-1-2020 at 03:15

Cheers for that, very interesting. I will definitely stick with ar.

Pyro_cat - 25-1-2020 at 19:50

Be interesting to add the HCL to the other 2 ingredients separately when they are not mixed to see which one causes the orange reaction or if it does.

B(a)P - 26-1-2020 at 00:51

I will do that and report back

j_sum1 - 26-1-2020 at 03:31

Not really much need.
The Ti(IV) peroxo complex is very strongly coloured and is well known. It is pretty clear what is happening.

The better question is how the Ti came to contaminate the acid. My best guess is that it is from TiO2 used to colour polymer containers used in production, storage or transportation. Maybe a degraded pvc vessel.

Next HCl I buy will be a different brand: pool chemical stored in clear containers. See if that makes a difference.

woelen - 29-1-2020 at 02:47

Very annoying to have metal impurities in HCl.

I myself have the same issue with hardware store HCl. The 30% stuff we can buy here has a yellow color, which is mostly due to presence of iron (a dilute solution of the acid turns bright blue on addition of a solution of K4Fe(CN)6, yellow prussiate of potash).

Every now and then I distill some of this acid to make very pure appr. 25% HCl. That acid is completely colorless like water.

I do the following in 300 ml batches:

- Build up an all-glass distillation apparatus with the 30% acid (250 ml in a 500 ml flask) in the round bottom boiling flask. Add appr. 20% of its volume of water, in order to make appr. 25% acid.
- Connect a receiver flask, with a little distilled water in it (10 ml or so and swirl around to make it wet inside completely).
- Start distilling the acid. Initially, a lot of fumes are produced and not all of the fumes dissolve in the little water of the receiving flask. After a few minutes, however, the acid nicely distills over and collects in the receiving flask. Initially, you get dense fumes of HCl, hence the water in the receiving flask. Be sure to not vent these initial fumes into the room. I use a flexible thin PVC hose to lead this gas outside through a window, set ajar.
- Keep on distilling until appr. 85% of the liquid is distilled. The remaining liquid is deep yellow. In the receiving flask there is appr. 250 ml of perfectly clear and colorless acid.

The acid in the receiving flask is appr. 25%.

The liquid in the boiling flask can be discarded, or kept for cleaning purposes (I keep it, it is useful for rinsing test tubes with alkaline precipitates and for descaling things).

You can concentrate the pure acid by heating some of the impure 30% acid and leading the gas from that through the 25% acid. You must be careful not to have suck-back and the use of an intermediate flask is advised. I myself do not do this last step. I am happy with the very pure 25% acid. It works fine for nearly all experiments. For the few experiments, which require more concentrated acid, I use AR-grade 37% acid. That expensive acid I hardly use, more than 90% of the experiments I do with this 25% purified acid.

[Edited on 29-1-20 by woelen]