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Comment by exmadscientist | Hacker News Reader

> there's no technical reason to use poison

Yes, there is. Methanol and ethanol are very chemically similar and small amounts of methanol in your ethanol is usually acceptable from a chemical standpoint. But denatonium benzoate is not like ethanol, and can be a contaminant that destroys the process.

To get around this, you either have to find old-fashioned methylated spirits in very high purity, pay the alcohol taxes (which are stratospheric on 200 proof...), or file a crapton of paperwork to buy ethanol tax-free because you're doing chemistry things with it, not drinking it. The latter is what big operations do, but it's a giant pain in the ass if you are not a big operation and you just need moderate volumes of high purity alcohol for your critical cleaning operations....

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Labs aren't buying their stuff at Walmart, so I don't know why they'd by affected by any remotely reasonable law. The supply houses can keep selling methylated alcohol, but let's get the unnecessary poisons off store shelves and out of consumer cabinets.

No disagreement from me. I'm just saying there is a technical reason to use methanol denaturants sometimes.

> exmadscientist

Username checks out, any fun stories to share? I find most people who've worked in lab's have at least one.

Not as many as I'd like. Or maybe I just need to become a better storyteller.

Probably the latter. You might not even need to become better; just tell a few more stories and find yourself shocked at what we all find entertaining.

Except 100% ethanol would be considered a poison too. 100ml (4 ounces) could likely kill a 5 year old child. https://www.alcohol.org.nz/alcohol-its-effects/health-effect...

Who is giving 5 year olds 100% pure ethanol or ethanol at all for that matter?

Nobody gives it to them. 5-year-olds have sufficient intelligence and dexterity to get into all kinds of things, but don't necessarily know not to eat/drink/play with it, etc.

I'm somewhat of a lush and the idea of drinking two shots of 190 proof ethanol sounds like an excellent way to purge my stomach. I'd be impressed by any baby who could keep that down even if they got past the rank stench. Any baby that extreme would almost certainly survive.

And if you denature that, it's almost twice as toxic because methanol is so much nastier. Hopefully I don't need to point out why completely banning alcohols is a rather different conversation.

Absolute alcohol (200 proof ethanol) has a number of ways to kill you. It's slightly poisonous on its own. It's a massively powerful dessicator, so it can turn tissue into leather. And, if you've got industrial quantities of the stuff, it's probably not quite pure: turns out you can't just distill it past 190 proof due to water and ethanol forming an azeotrope. To push past that limit requires azeotropic distillation using such fun substances as cyclohexane, benzene, and isooctane, and they definitely do exist in the final distillation output. Most of these are rather more poisonous than ethanol on their own, so you don't want to drink them.

So don't bloody well drink anything above 190 proof, ever, no exceptions! Though when you're going through 55-gallon drums of it to clean clean-room equipment, a lot of it tends to end up in the air... turns out you can get enough alcohol in the air to get noticeable effects on you.

Like I said, lots of ways to kill you.

I read a WWII book about wartime pilots doing crazy shit. At one point the wings freeze over and the alcohol spritzers for de-icing are all plugged up, so somehow it vents into the cabin and gets the pilots drunk from the fumes. I think they ended up landing on a glacier in the fog, thinking they were about to hit water.

You left out pressure-swing distillation which doesn't require any "fun" substances to break the azeotrope. I'm not sure if it's used commercially for ethanol though? I believe it's more expensive.

Also the really high purity stuff (for HPLC and the like) has the "fun" chemicals removed from it and a chemical analysis printed on the side of the jug. Benzene content can be well below safe drinking water standards depending on the product. Pretty sure you'd be paying more at that point than just buying taxed vodka though.

Sounds like there are some interesting stories behind this advice ...

100% ethanol is generally made by a molecular sieve and it does not require any sort of poison. I have drank it before, and it is very strong of course, but no more dangerous than everclear. If there is any poisonous chemical other than ethanol in it, it is by definition not 100% ethanol. You can actually trivially make your own by purchasing molecular sieve material online. Of course I would never do that besides distilling is illegal :)

Fun fact though: it’s not 100% ethanol for long after you open the bottle because it will absorb water from the air until you hit the azeotropic limit.

I started using Everclear as a kitchen disinfectant when Covid started. It's 190 proof, kills germs, and it's non-toxic (in small amounts) so you can use it on food surfaces like cutting boards. A big bottle is surprisingly affordable in the US and after 2 years I still have half a bottle left.

Downsides: It's flammable and you wouldn't want it accessible with kids around.

> It’s 190 proof

Everclear is 151 in states where it’s not legal to sell spirits of higher proof than that (for example, California).

I discovered this little disappointment while attempting a limoncello recipe that called for real Everclear and all I could legally buy was the 151 proof version.

Except this is why chemistry is less entrepreneurial - you can't just set up a lab in your shed (for better and for worse)

And so now I write code for a living instead of trying to push the frontiers of medical chemistry :)

FYI I fully get why many chemicals are fully regulated. I recall a funny story from uni and how only the big boss head of the entire chemistry org had the authorisation to handle lysergic acid (precursor to LSD) and he had to be supervised while pouring it/measuring it for your experiment.

As kid I had a reprint of the Boy Mechanic from the turn of the 20th century. Sooo many of the activities involved going to a pharmacy and getting X dangerous compound or element that I doubt most pharmacies today even carry let alone would sell to a 12 year old kid.

> Except this is why chemistry is less entrepreneurial - you can't just set up a lab in your shed (for better and for worse)

Given the number of wannabes PhD in chemistry having peaceful religious beliefs that are entering in EU every year, this is really for the better.

'tis a tranquilizing prospect.

Can you distill out the denatonium? I'm guessing it would just be too much work to make it worth it if so?

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