I’ve written before about all the fun you can have in a lab with compressed gas cylinders. We use the things all the time in chemistry, but as pieces of apparatus, they can only be pushed so far. The problem is that they demonstrate their unhappiness by venting great quantities of stuff that you’d rather not breathe (if you’re lucky), or by taking off like an unguided missile and punching holes in the walls and ceilings (if you’re not). That latter behavior is flat-out guaranteed to show up if you abuse them – for one of the more spectacular examples, see here.
I’ve never had one take off on me, fortunately, but I haven’t always stuck to the straight and narrow with the things, either. My worst behavior has usually been with lecture bottles, the dilettante-sized gas cylinders that bench chemists often use. Most chemistry departments have a few of these sitting around, generally charged with foul reagents that are needed every three or four years or so. Sulfur dioxide, boron trifluoride, phosphine – that’s the sort of thing. They’re low-use almost by definition. If there’s a regular need for a gaseous reagent, you buy larger cylinders of it, because lecture bottles are by far the most expensive way to go.
In graduate school, I was setting up some Prins reactions, which take some sort of acid component to make them run. If you use an aqueous one, you generally get an alcohol out of them (from water picking up the final cation), but if you go anhydrous you can get all sorts of other compounds. I needed a bromide, so anhydrous hydrogen bromide it was.
We had a fairly crusty lecture bottle of it around, and I eventually located some dubious-looking small regulator valves. I picked the least-corroded looking one and screwed it on. Lecture bottles have a main metal-faucet style valve up at the top, like all gas cylinders, and once you open that it’s up to the regulator valve to stop things down to manageable flows. I had my reaction set up, so I worked some tubing onto the thing and had a go at opening it up.
No dice. Boy, was that thing tight. I reached into the hood and wrestled around with it, to no avail. I took it out and got a better grip in another part of my hood, away from my reaction setup. Tighter than two quarts of fresh frogs in a half-pint pickle pot, as Walt Kelly once put it – the valve wouldn’t budge.
I’ll skip over a couple of intermediate stages and cut right to the final scene, which is me clutching the darn lecture bottle to my chest, hopping around the lab grunting and cursing as I put all my strength into trying to force the stupid valve open. You won’t see a pictograph of that method in the instruction booklet, I’m pretty sure. A recording of what happened next would have gone something like this: “Urk! Unk! Ark! WHOA!”
The valve opened, finally responding to my Conan-the-Barbarian technique, and the cheap regulator then hissed out an orange cloud of gaseous HBr right into my shirt pocket. Not a good storage compartment, actually. I whooped, shut the valve, laid the gas cylinder down fast and stripped off my shirt where I stood. You haven’t really lived in a lab until you’ve taken off your clothes in it, I always say. I staked my claim to this one by standing in it shirtless, splashing saturated sodium bicarbonate on my chest, and glaring at the remains of what used to be one of my favorite shirts.