Sciencemadness Discussion Board - UK: Hydrochloric acid, phosphoric acid, and hexamine now restricted/banned!

UK: Hydrochloric acid, phosphoric acid, and hexamine now restricted/banned!

SplendidAcylation - 14-12-2023 at 02:49

I'm surprised there isn't already a thread on this topic, but there doesn't seem to be...

I was just checking the list of regulated explosive precursors and poisons on the UK government website, to see if barium compounds were there (they are!), and I came upon something that I could not quite believe.

As of 1st October 2023, the government have sneaked some new additions to the list of regulated chemicals, three of which in particular caught my attention:

Hydrochloric acid (10% w/w)
Phosphoric acid (30% w/w)
Hexamine

Here is the full list here:
https://www.gov.uk/government/publications/supplying-explosi...

Is this really happening, or am I hallucinating (perhaps I have inadvertently inhaled too much nickel vapours in my recent experiments)?

Most of the things on those lists are vaguely understandable, but hydrochloric acid, how on earth is this an explosive precursor?

Until now, i have taken it for granted that hydrochloric acid is the one strong mineral acid that is, and always would remain, freely accessible, due to the fact that it isn't involved with explosive production in any way that I am aware of.

Now, to be fair, it isn't a huge problem, because it is possible to distil hydrochloric acid, obtaining the azeotropic concentration of 20.2% w/w, but that is nowhere near the 35% concentration that was previously readily available.

As for phosphoric acid, I suppose it is possible to concentrate phosphoric acid by evaporating off the water somewhat, however i have a vague memory that it polymerizes or something, with prolonged boiling.

As for hexamine, this can of course be made from ammonia and formaldehyde.

So all in all, it isn't really a huge problem for me, at least, but I just find it totally shocking and quite scary, to be honest!

Apologies if I made some errors, this is really a rushed post, I look forward to discussing the chemistry by which we can circumvent these new restrictions in further posts.

I think it might be a good idea to go around various outdoor/camping stores to see if they have any hexamine tablets in stock, it is possible they might have not received the memo.

Hexamine is very useful in organic chemistry, for the Delepine reaction and the Sommelet, among others I'm sure.

There are also still some listings for hydroponic pH down on eBay, those are 81% phosphoric acid, so it might be worth buying some, before they realize they are committing a crime and remove their listings...

RU_KLO - 14-12-2023 at 04:17

I dont know how is it in UK, but in my country, buying, producing or storing is the same problem (I think that producing is harsher). So if they knock at your door....

unionised - 14-12-2023 at 05:29

Re. "
As for hexamine, this can of course be made from ammonia and formaldehyde."
Only if you can still get them
formaldehyde 5% w/w (CAS RN 50-00-0)
Is on that list.

SplendidAcylation - 14-12-2023 at 05:38

@unionised,

Formaldehyde is under the "Reportable poisons" category;

Anything under the "Reportable" headings are still available legally, however suspicious transactions must be reported.

Anything under the "Regulated" headings are illegal to sell/buy/possess without a licence...

unionised - 14-12-2023 at 05:50

If I was a shop, I'd think really hard about not stocking formaldehyde- just to save myself paperwork / hassle/ getting lumbered with a product I wouldn't be able to sell if they changed the rules.
Anyone feel like distilling acetal plastic shavings?

Sir_Gawain - 14-12-2023 at 07:54

Distilling acetal yields formaldehyde?

BJ68 - 15-12-2023 at 00:23

https://www.reddit.com/r/brexit/comments/b7dgsz/2000years_la...

bj68

SplendidAcylation - 15-12-2023 at 02:43

Quote: Originally posted by unionised

If I was a shop, I'd think really hard about not stocking formaldehyde- just to save myself paperwork / hassle/ getting lumbered with a product I wouldn't be able to sell if they changed the rules.
Anyone feel like distilling acetal plastic shavings?

Well if they did change the rules they would probably limit the concentration rather than ban it completely, so you'd just have to dilute the stocks you had

Paraformaldehyde isn't listed there, so I'm not sure if that is even counted at all.

Anyway, there are still plenty of places where you can buy formaldehyde at the moment in the UK.

It can also be made, of course, by passing methanol vapour over a heated coil; Catalytic dehydrogenation.

@BJ68

clearly_not_atara - 15-12-2023 at 10:47

Phosphoric acid can indeed be concentrated by heating. Its high affinity for water means that this requires high temperatures. At all concentrations above 85%, when in the liquid phase, phosphoric acid exists as a mixture of oligomers, eventually forming a negative azeotrope with bp ~860 C and a molar composition of roughly 1:1 H3P3O9:P2O5.

IIRC, if phosphoric acid is concentrated just the right amount, it will all crystallize as pure diphosphoric acid, H4P2O7, under standard conditions.

[edit by mod]
Removed accidental smilie.

[Edited on 14-4-2024 by j_sum1]

Alkoholvergiftung - 15-12-2023 at 23:02

clearly_not_atara what would be the best material for boiling phosphoric acid? copper? it attacks glas so its on the long term no option.

Keras - 16-12-2023 at 01:42

Really, I think the best way to ‘concentrate’ phosphoric acid is to add phosphorus oxide to it until you reach 100%. Phosphorus oxide is not easy to source, but it is not restricted, contrarily to phosphorus itself.

Conure - 24-1-2024 at 10:20

Damn, you brittish people are ahead of us in sweden. We can still order 30% HCl and 85% H3PO4. However in 2025 NaOH and KOH will be gone from the public. The motivation is that it causes too many accidents.

Belowzero - 24-1-2024 at 10:26

Quote: Originally posted by Conure

Damn, you brittish people are ahead of us in sweden. We can still order 30% HCl and 85% H3PO4. However in 2025 NaOH and KOH will be gone from the public. The motivation is that it causes too many accidents.

Pretty sure more accidents happen with water, perhaps they should do that next.

clearly_not_atara - 25-1-2024 at 07:33

Quote: Originally posted by Alkoholvergiftung

clearly_not_atara what would be the best material for boiling phosphoric acid? copper? it attacks glas so its on the long term no option.

I think you could use graphite but I would suggest trying a small amount first. But glass has decent resistance at the concentrations we're usually interested in. It's only when you get to very high temperatures and concentrations that the attack on glass becomes severe.

EDIT: in particular, decomposition of monoammonium phosphate in a graphite crucible might be a possibility

[Edited on 25-1-2024 by clearly_not_atara]

ManyInterests - 13-4-2024 at 17:27

This is just nuts. I bought a few packs of hexamine fuel tablets recently even though I have too much hexamine. It is stuff like this that really irks me. It's also why I stocked up on a lot of sulfuric acid and nitrates.

EF2000 - 14-4-2024 at 01:40

Quote: Originally posted by SplendidAcylation

Most of the things on those lists are vaguely understandable, but hydrochloric acid, how on earth is this an explosive precursor?

Until now, i have taken it for granted that hydrochloric acid is the one strong mineral acid that is, and always would remain, freely accessible, due to the fact that it isn't involved with explosive production in any way that I am aware of.

Unfortunately, it really is an explosive precursor. TATP syntesis requires any relatively strong mineral acid: sulfuric, nitric, hydrochloric, phosphoric. Hydrochloric is said to give best results. Phosphoric acid can also be used to prepare HMTD, though usually it's done with citric acid. Sulfuric and nitric are already regulated, so now they came for hydrochloric and phosphoric. (One day they'll come for citric acid, and there would be no more lemons and oranges in the UK.)

LookingForAnswers - 17-4-2024 at 15:24

I've seen in Home Bargains "killrock" descaler ( black one ) and there is some small concentrations of H3PO4. i dont remember volume but maybe someone will be interested