FYI: this is just me rambling about Polish bit of legislation from 2004 about reduced access to the drug, poison and explosives precursors. It's long, it's likely boring and you know the drill at this point. Read at your own risk, by all means, comment if you like or don't like what I said.
So, this is something many among you (ones living in the USA or Canada in particular) could find as shocking, but there are places where you can't buy most inorganic acids. And the ones you can buy are diluted to a point of near uselessness. Sulphuric acid? Yeah, if you are OK with the 30% battery-grade one. Hydrochloric (muriatic) acid? Fuck off! You want that to make drugs, aren't you?! Methanol? See above.
Oddly enough, I can buy 99% toluene from a hardware store. It's on a more restricted list than most drug precursors, but because of the trace sulphur impurity it's suddenly 'safe'. No, it isn't. Everyone who isn't a clueless legislator knows it. Or perhaps I'm not giving them enough credit?
Of course, it's not that we suddenly don't have any of those chemicals. They just aren't available to any private entity. And here's the main problem with the legislation: I could open a carpet cleaning business, buy whole barrel loads of that stuff, claim bankruptcy and as long I can pay off the debts and fees, I can keep all the things I bought. Seriously, I even checked it with a lawyer (family friend). So it doesn't stop anyone who isn't sleazy. But that's not for me. Apart from the fact I need maybe a few things in fairly small quantities, I don't want to have a police ride in the house next time they'll have a drug bust anywhere nearby.
But you can make most of this stuff. How? Well, you can buy any laboratory-grade glass and instruments as a private entity. If you pay in cash, then it's even an anonymous transaction. The only reason anyone wanted my name, was to contact me when the stuff I ordered wasn't on hand and they had to get it in. I wasn't carded at any time, so I'm guessing that unless I'd say something outrageous (like Anonymus van Pseudonym), they would take any name. Now all you need is to know a bit about chemistry, find the relevant documents and do your own chemicals. Muriatic acid? Leblanc process attached to a water-based air scrubber (tip: do multiple iterations of scrubbing. It's a lot safer and you get more, progressively more diluted, acid). Methanol? Bulk pyrolysis of the wood. Almost everything is obtainable, one way or another. Chemists had to do a lot of the legwork before lab supply companies were just delivering that stuff.
So who is even prevented from doing chemistry? That's easy: people who are or/and: lazy, uneducated, unmotivated, incapable of research or extremely cheap*. You know, the people who are most likely to end up injuring or killing themselves or others due to negligence. Or people who would just buy this stuff and lose interest in two days. And you have to know your stuff to store some of those chemicals in a manner that's safe.
Honestly, it's almost genius in design. The only people who stick with it are nerds who likely started from wanting to make stuff like nitroglycerin or thermite but ended up reading on common ion effect, substance separation, cooling mechanisms and (from today perspective) rather obscure chemistry bits and texts. If you want to pursue chemistry in any way other than pure theory, then you have to be resourceful, do the research and have the passion. You have to learn about methods used in labs in XIX century because today no self-respecting lab would make some of those chemicals in-house (why waste time if you can get it for pocket change per cannister?). It's as if this dumb legislation was made to increase the numbers of chemistry and science nerds!
Even if it's only one person per school, and only half of them would go to study chemistry (or pharmacology, heh), that's still a considerable amount of people passionate about chemistry and science out of spite and as a response to artificial limitations. What could be better?
Well, chemistry sets come to mind. Even back when those had any acids or volatile solvents in them, they were more expensive than the street value of anything you could make with it. But I guess it's about preventing drug lords, not small guys. Not that it worked that well, considering the above points.
* - Or poor. That's the only detriment. Though, it's not like I'm swimming in cash myself.
By your own admission, the process greatly reduces the number of potential perpetrators with means. By dragging out the process and requiring more labor and planning, it diminishes motive - if I can head down to the chemist's to buy some acid to splash in your face, infidel, I'm a lot more likely to do it than if I have to whip out my bunsen burner and titrate for the next 30 hours because my crime of passion has just become a crime of premeditation. Opportunity? There are far more people who smoke pot than grow pot and it's literally a weed.
Had a buddy. Was interested in GHB right about the time it was outlawed, long before it became one of two favored date-rape drugs. We had a conversation at the time - the precursors were readily available, but the price on enough precursor to make 5ml of GHB was every bit as high as the price on enough precursor to make 5L of GHB because if you intended to make 5L of GHB outside of a commercial chemical enterprise, you were guilty of trafficking not possession.
So my buddy said fukkit and made a fuckin' gallon and a half of GHB.
He hadn't gone through a soda can's worth before he decided he wanted nothing more to do with GHB. I guess he made himself sleep for three days by accident once. That amount of controlled substance was an attractive nuisance; you can't show it to anybody, you can't sell it, you can't raise the attention of any local narcs because you're looking at Big Time if you get busted. So he poured about 80% of it down the drain and moved on to other things.
It's a pain in the ass to buy cold medicine in the United States. You can still get it, but you can get it about one cold at a time. This is because the active ingredient pseudoephedrine is a vital precursor to crystal methamphetamine... but you need more than one cold's worth. the underworld adapted but now you aren't talking about one couple cooking in the rental apartment, you're talking about a criminal enterprise which you can prosecute appropriately.
As a thought experiment, let's pretend you're a jihadi hell-bent on annihilation of your fellow Polish citizens. You're clever, you're intent, you're patient. Your goal is not to advance your own knowledge, your goal is to devise maximum bloodletting. As such, you will likely find the recipe and procurement process that maximizes pain and minimizes effort. While you are doing this, you are buying chemicals, going to stores, becoming known, etc. Pretty soon you're the mad bomber and it's far more than local police watching you; you're now a target for Interpol and there are surveillance vans outside your mom's house.
If, on the other hand, you're an innocent experimenter (as you are), your purchases and behavior very much do not match those of jihadi terrorists. You likely aren't purchasing exclusively precursors that lead to terror weapons. Sure, you've got some high molarity acid but there's a lot that can't be done without high molarity acid and they know where you live, they know where you go to church, they know who you talk to and they know that should you decide to shift towards terrorism they'll probably know before you do. The entire pattern of your behavior will change.
A qassam rocket is literally pipe, sugar, fertilizer, TNT, a cartridge and some BBs. The chemistry is pretty well settled, far less sophisticated than what you're doing and the materials are much more readily available. Mossad got the guy who came up with them anyway. Meanwhile, nearly all IEDs have a particular Timex watch at their hearts. Sure, there's a million different ways to do it but that one Timex is easy to get, easy to mod, and doesn't require any improvisation.