WE DID IT: FLUORINE ISOLATED!! (Patreon)

After months of work, I've finally done it...I isolated fluorine gas in my garage, and it was CRAZY!

First, lemme go over the setup and how we got here. At first, I wanted to try the classic HF/KF electrolysis method, by distilling anhydrous HF and mixing it with raw potassium fluoride to get a low-melting electrolyte that could be electrolyzed into fluorine with graphite electrodes. The issue: anhydrous HF is stupidly hard to work with, and I never made more than a few milliliters.

So I searched through some papers and figured out that HF isn't even necessary...rigorously-dried potassium bifluoride (KHF2) can be melting and used directly! I attempted this pathway several months ago with a V-shaped electrolysis cell made from copper, as described in a 1931 paper by L. M. Dennis. This time, the issue was the cell dimensions. The 1" copper pipes used to make it were too small, and electrolytic corrosion started to affect the cell. More critically, however, the reagent purity became an issue: even a few percent silicon in the KHF2 (or even graphite) causes a glassy layer to build up on the electrodes and insulate from further electrolysis. Before switching to a purer electrolyte, I also tried a steel electrolysis cell with more optimal geometry, but found that molten KHF2 attacks steel...fun.

For this run, I used a custom CNC'd copper electrolysis cell (thanks JLCPCB), with electrodes insulated by Teflon tape. Both the KHF2 electrolyte and graphite electrodes were +99% purity, with negligible silicon content, and the anode (where the fluorine collects) was optimized for the correct current density. A digital PID controller monitored the temperature and kept it around 290C...I used a cheap Walmart hotplate I got for $15, lol. Oh, and the KHF2 was dried for 48 hours at 130C.

On power-up, they setup draws 10A at about 10V, and spews about 30mL of F2 every minute. I first tested the setup on CaCl2 solution to ensure I was getting fluorine (which produces a white CaF2 precipitate) and not just ozone or oxygen from leftover water. Then, once I had confirmed fluorine was present, I performed the following reactions (I'm gonna just list them, since there were a few):

1. Iodine: melted and boiled, forming brown iodine monofluoride near the bottom and liquid IF5 closer to the fluorine. A pale flame also formed as the iodine was heated (picture above, in the test tube).

2. Steel wool: only tested in open air, not enough F2 flow to ignite

3. Red phosphorus: ignited immediately, burned like normal (maybe a bit brighter). Wasn't a very wise decision, since PF3 is almost as toxic as phosgene...glad I had a fume hood.

4. Acetone: nothing at first, but within a few seconds began igniting and popping violently. At times detonated with louder bangs, splashing acetone out.

5. Water: similar to acetone, at least when confined to a test tube (in a large beaker, it did little besides fume). After a few seconds detonated with a loud bang, which somehow didn't shatter the test tube (mid-detonation pic seen above).

6. Sulfur: burned with a pale blue-white flame when immersed into a fluorine atmosphere (picture above)

7. Butane: a flask was filled with butane and fluorine was flowed in. The result was a yellow-white flame from the fluorine as it entered, and a lot of soot...definitely looked pretty cool!

8. Magnesium (powder): caught fire immediately when immersed into a fluorine-filled flask, sizzled angrily, and was gone in less than a second.

9. Paper: the direct output was not enough to react with the paper, but when dropped into pure fluorine, it caught fire and vanished almost immediately.

10. Meat: burned and sizzled a little initially, but as the fluorine was depleted, it smoked and became ghostly-white, with a cracked, dry texture.

11. Toluene: this might've exploded had I treated it like acetone and water (test tube and slow F2 exposure), but I dripped it into a flask (seen above). It burned brightly with a VERY tall flame column and a lot of soot...maybe the tall flame was because the carbon soot was burning away itself!

12. Sodium: as a solid bead, it surprisingly was less vigorous than the magnesium. It burned away most of the F2 pretty quickly and then passivated. Even a jet of pure fluorine inside the flask (with external heating) failed to ignite it.

13. Candle (already burning): flame became brighter and, similar to toluene, much thinner and taller.

14. Nitrile glove clipping: surprisingly, this did nothing

15. Diethylamine: dripped into the same flask as the glove clipping to prove fluorine was present. Ignited immediately and burned brightly, but fairly normal.

16. Hydrogen (unintentional): towards the end, a few big fluorine bubbles managed to escape into the hydrogen side of the electrolysis cell, causing several loud explosions. Not powerful enough to fling molten KHF2 everywhere or pop the top off the cell, but very similar in intensity to oxyhydrogen explosions!

Idk if I'll be firing up the fluorine generator again any time soon, but if I do, what do you think I should try? Lemme know, and if you're lucky, it might end up in this month's video...I am tempted to fire it up again, just to get some bigger, more dramatic shots (compared to some of my other videos, these were shot pretty small and distant, and I'd love to get more ChemicalForce-style close-ups)!