Modern fertilizer manufacturing uses the Haber-Bosch and Ostwald processes to fix aerial nitrogen as ammonia, then oxidize the ammonia to nitric acid. Having already created a Haber-Bosch reactor for ammonia production, [Markus Bindhammer] took the obvious next step and created an Ostwald reactor to make nitric acid.
[Markus]’s first step was to build a sturdy frame for his apparatus, since most inexpensive lab stands are light and tip over easily – not a good trait in the best of times, but particularly undesirable when working with nitrogen dioxide and nitric acid. Instead, [Markus] built a frame out of aluminium extrusion, T-nuts, threaded rods, pipe clamps, and a few cut pieces of aluminium.
Once the frame was built, [Markus] mounted a section of quartz glass tubing above a gas burner intended for camping, and connected the output of the quartz tube to a gas washing bottle. The high-temperature resistant quartz tube held a mixture of alumina and platinum wool (as we’ve seen him use before), which acted as a catalyst for the oxidation of ammonia. The input to the tube was connected to a container of ammonia solution, and the output of the gas washing bottle fed into a solution of universal pH indicator. A vacuum ejector pulled a mixture of air and ammonia vapors through the whole system, and a copper wool flashback arrestor kept that mixture from having explosive side reactions.
After [Markus] started up the ejector and lit the burner, it still took a few hours of experimentation to get the conditions right. The issue seems to be that even with catalysis, ammonia won’t oxidize to nitrogen oxides at too low a temperature, and nitrogen oxides break down to nitrogen and oxygen at too high a temperature. Eventually, though, he managed to get the flow rate right and was rewarded with the tell-tale brown fumes of nitrogen dioxide in the gas washing bottle. The universal indicator also turned red, further confirming that he had made nitric acid.
Thanks to the platinum catalyst, this reactor does have the advantage of not relying on high voltages to make nitric acid. Of course, you’ll still need get ammonia somehow.
For fertilizer, eh? ;)
might get you on a list…
List, very old-fashioned… Everyone is on the list now. We have supercomputers that can watch ten billion people 24/7, we don’t need a list of shady guys that some gumshoe has to watch with a pair of binoculars and a parabolic antenna from a van like a spyXspy comic strip or an episode of Miami Vice. The list is everyone
“you’ll still need get ammonia somehow.”
my neighbor has horses and I have cats. instead of a fancy set of lab glassware you can simply put a still on top of a 30 qt pot. Of course boiling big pots of pee overnight will wake the neighbors.
Alas, not everyone’s piss is suitable for leaving “free gunpowder, frogt-“ sizes stockpiles of ammonium nitrate in all the places a frenchman would think is a good place to store the caustic lye and portland cement and iron oxide that is really red phosporous and 1920 just flew by, now didn’t it?
Nitric acid is REALLY nasty stuff. I accidentally spilled just a little bit of it on my class notes in my high school chemistry class and it burned through several pages. By “burned” I mean just that … it left large holes with blackened edges.
I can also tell you that bromine wreaks havoc on your nostrils if you somehow get a whiff of it.
Probably no surprise that I got my degree in electronics, not chemical engineering.
During the whole Iran fracas I remember seeing some cell phone footage of some guy over there driving past a rocket propellant plant that got hit by an airstrike… HUGE clouds of dense reddish-orange smoke billowing out of vats of burning nitric acid and other associated chemicals, obviously very dense smoke that didn’t rise up but hung around close to the ground and covered the highway…
I was like “For the love of God, turn around! It’s not worth it, don’t go to work today!” …But the driver just kept on driving. Right into the fumes. I hope they didn’t cheap out on the cabin air filter or weather stripping. I can’t believe somebody would just thoughtlessly drive straight into such a situation, but I suppose it’s not common knowledge. Anybody else see the video I’m describing?
Public service announcement: if smoke is not plain white and rising straight up into the air, don’t go near it. If it’s weird colors and hangs around near the ground, get the heck out of there. Maybe it’s safe, but it’s not worth testing.
There was a Nitric Acid leak in southern Ohio this year. There was a mandatory evacuation and a no fly zone announced. Thankfully the hazzard was recognized immediately and there were no reports of injuries.
If you breathe nitric acid fumes, you will die…..2 days later. A grad student in my dept died from this. Amateurs need to know the dangers and take extreme precautions.
Fuming nitric acid is the best nitric acid.
Damnit
Put the youtube(!) video embeddings AFTER the Read More button
Clearly this guy has been watching Dr. Stone
Hmm, I think making my own nitric acid will stay at the bottom of my archaic photographic processes to master list. Maybe above boiling mercury and synthesizing ether.