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How Not to Do It

Nitric Acid And Your Lab Coat

Ah, the good old nitric acid/sulfuric acid nitration conditions. A classic reaction if ever there was one. But you don’t want to let it spray all over your lab coat – you really don’t.
I have a shirt like the coat in that photo, one that I got from a sulfuric acid splashback in 1984 or so. I still keep it in my drawer, to remind me. I stripped it off pretty fast once the acid solution sprayed on me, I can tell you, then reached for a bottle of saturated sodium bicarb and just turned it upside down over my chest. I came out fine; the shirt was never the same. I’ll bet whoever was wearing the coat in that link above got out of it pretty fast, too. But it’s a lot better to have that stuff hit your lab coat than it is to have it hit your skin.

43 comments on “Nitric Acid And Your Lab Coat”

  1. Vader says:

    A hot mixture of sulfuric and nitric acid on a cotton lab coat … Sounds like disposing of the ruined lab coat may not be straightforward. What are the regulations for guncotton?

  2. Anonymous says:

    Year ago I burned out a wart on my finger with conc sulfuric acid and it left a hole right down to the bone. It took months to heal and left a scar. But the wart ain’t coming back!

  3. d says:

    Even outside of the lab people should be aware of this! I was helping a buddy fix a jet ski over the summer during undergrad once and about halfway through we realized the battery was leaking sulfuric acid everywhere. I noticed when my arms started tingling/itching a little, and I immediately jumped in the lake.
    No damage done! But, my shirt disintegrated in the washing machine later that day. Could have been worse.

  4. Sven says:

    Had this pleasure as a undergrad. Needed a mixture of oleum and fuming nitric acid and got a good spill of the hot mixture over the sleve of my lab coat, which vanished in the split of a second. Luckily i got off with some minor burns, but i still have a small scar to remind me of what might have happend without the coat doing its job.

  5. HFM says:

    Heh. Reminds me of the first lab job I had. I was 17 and didn’t know squat. My first assignment was to prepare some dinitro-phthalates as starting material; yes, this was an academic med-chem lab, and I may not have been the only one who didn’t know squat. This particular compound had only been mentioned once in the literature – Chemische Berichte, 1890s. So I dutifully went down to the library’s deep backfile, found the paper, and read something like “equal parts fuming sulfuric acid and fuming nitric acid at 80C”. Beat my head against the wall for the better part of a month before someone explained to me that “fuming” was a term of art, not a description. (The regular stuff looked pretty fuming to me!)
    Miraculously, the only property damage I caused involved a pressurized column. (My training was “clamp that lid on and turn on the air supply”, so I did, and since nothing appeared to be happening I turned the air higher…)
    I became a biologist.

  6. A Nonny Mouse says:

    I want to know how sulphuric manages to find its way to places that you could never imagine. I’m so careful- arms’ length, in the fume hood, rinse the measuring cylinder……
    Come the trousers out of the washing machine and there are 2 holes on each cheek! How the hell did it manage to get there? I must confess that I have trousers that I keep for when I know that I am going to use sulphuric and they look a lot like that lab coat (actually, most of my labcoats at university used to look like that).

  7. Manny says:

    HF on skin is possibly the worst. Anyone know what to apply to affected areas of contact?

  8. Hap says:

    I think calcium gluconate (after lots of water?).
    There are supposed to be kits to apply in case of contact for people working with HF. This appears to give lots of detail about HF exposure treatments.

  9. Poison Ivy League says:

    Nitration using HNO3/H2SO4 is a sophomore organic lab experiment here. Inevitably at least one student in each section adds too quickly and we get a nice geyser…tempting fate, if you ask me

  10. oldnuke says:

    Had my own adventures with concentrated perchloric acid… I accidentally set fire to a roll of strip chart paper (remember that stuff and the purple ink? 🙂

  11. D. C. Sessions says:

    Can someone tell me why anyone is still using cotton labwear today instead of PTFE or other safety materials (Gore has a whole line of splash-protective materials!)

  12. AndrewD says:

    The most interesting (For certain definitions of interesting) nitration mixture accidents I have seen were plant scale. The first involved adding the organic to a cooled and stirred nitration acid charge. One day the operator forgot to start the agitator and ran the organic into the acid, then realising the agitator was off turned it on…
    The second involved adding Benzene to a stirred cooled mixed acid charge. The cooling failed, the standing procedure was to turn the agitator of and settle the mixture and the run the acid back to a storage tank. This was done and the acid tank started to rumble, there was a small explosion and a cloud of brown fumes, this wouldn’t have been too bad if there wasn’t a TV team on site making a business documentary about the chemical industry. (We belive the operator missed the split and put same benzene into the acid tank)

  13. Ryan says:

    Yeah, the picture is neat, but the advice is terrible (i.e. use a cotton lab coat).
    Cotton is only suited for applications where you need to keep your clothes (or your experiments) clean (in a rough sense). In the case of dangerous activity in a chemistry laboratory, I think fire-retardent NOMEX lab coats remain the gold standard – after all, fire probably remains the most likely catastrophic event.
    Then, if there is a major splash hazard, you can always add a PTFE or Butyl apron, and a face shield. As such you will be splash protected AND fire protected – and you can wear something a bit more comfortable than a PTFE suit for regular activity.

  14. LiqC says:

    I joined my first lab in high school, and they liked their glassware washed in chromic acid (K2Cr2O7 + H2SO4). You don’t need to make it fresh often (it does the job even when it’s green). Still, one day my buddy and I ran out of sulfuric acid, and when to get some from the bunker. It was in a 20L bottle, and we were hardly athletic. We may have left behind a small puddle of sulfuric acid, with the reasoning that by the time someone needs to go there it will soak into the cement…
    Needless to say, everyone’s lab coats looked like that. There was also special nerd chique in haveing little tears on the jeans, from microscopic splashes of the red devil.

  15. lt says:

    Wouldn’t a Nomex or PTFE lab coat be a potentially bad idea if you’re working with stuff that can be ignited by static electricity? Like solvent fumes, for example? That’s one reason why pyrotechnicians prefer cotton over wool, for example.

  16. Anonymous says:

    this lab coat looks like its full of the characteristic holes you get after washing. holes in pockets/around arm length are typical for wiping your hands on the coat. this definitely not a fresh spill.
    the lab coat and gloves are not meant to protect you from foreseeable risks, they are meant to provide some protection for accidental spills in otherwise safely conducted procedures.
    these PPE items buy you a few seconds, nothing more.
    cotton or even better wool is the most appropriate material for the purpose, in cases where a risk bigger than that truly exists more sturdy materials are the wrong answer!
    with conc. H2SO4? hard to believe, even if concentrated oleum is used this is an extremely slow and painful process. 0.1 M HCl i.m. is a useful pain model for human subjects. tissue is more resistant to acids than to bases. acid attacks common in southern asia only cause the most severe effects because victims have limited access to water and often do not rinse off the acid in time if at all.

  17. Anonymous says:

    As an undergrad I was generating chlorine gas using manganese dioxide and HCl. The reaction got away from me and I had my whole shirt front spattered with the mixture. It didn’t burn any holes, but when the red shirt came out of the laundry it had white spots where the reaction mixture had been. A mixture of MnO2 and HCl makes a very effective bleaching agent.

  18. gippgig says:

    Note that lead-acid batteries can explode (stray hydrogen; happened with my mother’s car – safely contained under the hood). I wore a face shield when I replaced my battery and keep a box of baking soda in the car (along with a bottle of citric acid for completeness (out of idle curiosity, what chemicals do other readers keep on hand?)). Also note that hardware stores sell sulfuric acid as a drain opener (wouldn’t it dissolve the pipe as well as the clog and user?); in one case there were gallon jugs of it on the shelf right next to the lye-based drain openers. Do they do that in earthquake country?

  19. Sympa says:

    @2, @16, @18: a friend was jumpstarting his car when the battery exploded. He rang the nearest doorbell and yelled ‘water water’ and he made it out fine. He did wear glasses, though.
    Now I always tell people: when you jumpstart, the ground is last to go on and first to go off… and that last connection point is NOT anywhere near the battery.

  20. D. C. Sessions says:

    Wouldn’t a Nomex or PTFE lab coat be a potentially bad idea if you’re working with stuff that can be ignited by static electricity?

    A long-solved problem. Incorporate a small amount of something conductive into the plastics (carbon is popular, and for all I know by now fiber has gotten cheap enough that it’s even structural) to reduce resistivity.
    Semiconductor electronics are sensitive to electrostatic discharges that are far below those required for igniting most chemical reactions. And if you’re working around the ones like nitrogen triodide, you had best be doing more than wearing antistatic clothing.

  21. lt says:

    @20 Is it a a long solved problem in the sense that most Nomex lab coats currently on sale are antistatic? I though that stuff is pretty specialized.

  22. Anonymous says:

    @16: No 2 here … I forgot to mention that I let the drop of acid soak in for half an hour. And yes, it hurt, but more like a needle going in so it was bearable.

  23. John Wayne says:

    Is that a tablet in the pocket of that labcoat? Shouldn’t that person be flipping through a yellowed copy of Larock looking for new reaction conditions? Man, I feel old …

  24. D. C. Sessions says:

    @20 Is it a a long solved problem in the sense that most Nomex lab coats currently on sale are antistatic?

    Damn if I know — I’m a retired EE. I do know that antistatic clothing is routine stuff for electronics, though, so the market can supply it — if there’s a demand.
    Which, I confess, is not in evidence.

  25. Wavefunction says:

    I remember creating patterns in my lab coat by burning holes in it using nitric and sulfuric acids.

  26. Anonymous says:

    When I was a kid about 12 years old I would get battery acid at the local garage and boil down to make it as concentrated as possible. I would use it to make nitric acid which I distilled from a sulfuric acid sodium nitrate mix using a retort, yes a real glass retort. I used the nitric acid for all kinds of things but my favorite was to dissolve silver coins to make silver nitrate which I used to make silver fulminate. Two things I discovered early on was my clothes were dissolving making my mom pretty POd, and I ended up with steaks of silver running down my arms and fingers blacken with silver. After those experiences I invested in a rubber apron but somehow still managed to get silver stains on my hands from time to time and the occasional nitric acid yellow stain as well.

  27. chemical says:

    I work for a research lab in the oil industry and deal a lot with crude oil samples. Pretty much everything in the lab is highly flammable. Our lab coats are Nomex.
    As far as static goes, solvents and waste are stored in metal containers and are grounded. Oil samples are typically stored live, meaning at the same conditions as it is in an oil reservoir — no oxygen.

  28. Dan says:

    @14 At least you had a story to tell for your ruined clothes. In both years of HS chemistry I ended up with a number of ruined shirts with tiny burn holes on the front/side. Most of them were in the area that was theoretically protected by my lab apron.
    In retrospect I think that was a demonstration of why hanging several dozen lab aprons on a single wall peg was an optimum method of transferring contaminants from the front of one apron to the back of the next.
    I never had a similar problem in my freshman chemistry lab college despite similar storage methods and similar experiments. I suppose it’s possible they cleaned the aprons more often; but suspect the difference between defaulting to 0.1 molar acid instead of 6.0 probably had more to do with the difference. This was all 15-20 years ago; and I’ve wondered if my college labs were overly cautious about the strength of the chemicals we were allowed to use; or if I should add letting teens play around with concentrated acids/bases to the list of reasons why my HS teachers were idiots.

  29. burns says:

    At our university we have a product called Diphoterine which comes in a spray can, and is extremely effective in mitigating acid burns. In the cases I have witnessed (one student sprayed in the face with neat sulfuric acid, another covered with aqueous HCl following work-up explosion) its immediate use completely alleviated the students’ burns and also prevented lasting damage. I would highly recommend any chemistry lab has a canister on hand.

  30. Nick K says:

    One possible explanation for the tiny holes in clothing caused by conc sulfuric acid is that it picks up static charge very easily when poured. No matter how careful one is, the last thread of the substance disintegrates, spraying tiny, electrically charged droplets everywhere.

  31. gippgig says:

    Speaking of lead-acid batteries, there is a type called absorbed glass mat (AGM) that doesn’t contain free liquid sulfuric acid; the electrolyte is absorbed in glass fibers. This offers a clear safety advantage (but an explosion would still be bad news).

  32. eyesoars says:

    FWIW, in HS I was one of the designees for mixing up dichromate cleaning solution. I remember at least once walking home and realizing that some small splatters had gotten on my jeans. Walked in the front door, got some scissors and started cutting holes in my jeans (to my mother’s shock). Also remember getting some perchloric acid on the corner of a lab notebook, and watching it slowly eat the remainder of the notebook over the course of the year.
    As an EE in high performance computing, as of 25 years ago, we could get two kinds of conductive lab coats. One sort had embedded metal wires — strictly forbidden in our engineering labs, as after a few washes, they would start to come apart, fall out, and short out electronics — and those with carbon fibers woven in. Low enough resistance to keep static charges down, high enough not to short out equipment if the threads fell onto circuit boards.

  33. Anonymous says:

    Question for all of you (probably industry) chemists advocating butyl aprons – what covers your arms? Do you use the clumsy, long-sleeved butyl gloves? Or do you just rely on arms being easier to wash than your torso?

  34. Some idiot says:

    Yes, Calcium Gluconate after lots of water. It works. Almost personal experience. A friend had fluke accident (wearing butyl kit, safety glasses (prescription) and face shield). Somehow (we still don’t know how) a concentrated aqueous solution of aqueous HF got past her face shield and hit her in the face. Some on the arm too (from taking the glasses off after she had taken gloves off). Straight under water and washed heaps. But the stinging didn’t stop until the calcium gluconate came on. That was very effective.
    I don’t know what the precise recommendations are now (I don’t do HF stuff) but from that experience I would recommend a very fast (but effective) wash with lots of water, and then calcium gluconate cream.
    Her glasses partially melted. Her face escaped with a minor, almost unnoticeable scar. The interesting point is that the scar was the spot where the cream was applied latest (i.e. after a while, where the stinging had receded other places). Not nice stuff.

  35. Some idiot says:

    Another H2SO4/HNO3 story… Another friend was a lab tutor at uni and was preparing some fuming nitric for the next lab classes. We are talking about a 4 L RB containing 3 L of a mixture of conc. H2SO4 and conc. HNO3. He was distilling out the fuming nitric using a fishtail bunsen under a wire gauze. The whole thing was going nicely when the RB cracked all the way around and a wave of refluxing H2SO4/HNO3 came splashing out, and hit him in the chest. He has very good reflexes… Hopped back and ripped off his lab coat and shirt in one movement, threw it in a sink, and then hosed himself down.
    He was fine (basically no burns at all). However, the fronts of the lab coat and the shirt just vanished…

  36. overthetop says:

    I did my graduate work in a synthetic carbohydrate chemistry lab. By far the most common TLC dip was a mixture of sulfuric acid in EtOH, which constantly dripped everywhere when you applied heat from the heat gun. I remember constantly burning holes in my sleeve by accidentally brushing against the open beaker in the corner of the fume hood or the drips left here or there.

  37. metal wrangler says:

    I used to work in a dioxin analysis lab. One of the steps was a conc. sulfuric acid shake. Even though we had all sorts of PPE there were always tiny holes in the hems of my pants!
    In high school I made some silver acetate solution for my chem teacher. I had black Ag stains all over my hands for weeks. Freaked out my parents!

  38. JH says:

    A friend was pipetting chlorosulfonic acid. Oops, the pipette was leaking, making a small stream down his labcoat next to the row of buttons. He first noticed the fumes and then his labcoat opening with the buttons still closed.

  39. JF says:

    Oh, this takes me back. I am no professional chemist, but I did do entry-level lab work for a year or so, way back in the early 90s. We used 93% sulfuric acid mixed with potassium dichromate as a cleaner for some of our equipment. All the lab coats had holes eaten out of them from the acid, with nice bleached rings around the edges from the dichromate.

  40. Oblarg says:

    Back in high school I did this to one of my robotics team t-shirts during AP Chem. Didn’t notice the massive hole until a couple days later when I pulled it out of the laundry.

  41. David says:

    #19 – on the subject of car battery explosions when jumpstarting – this is almost always done outside, so I can’t get my head round why the H2 doesn’t just dissipate up into the sky within a few seconds of opening the hood. Or simply get blown away by the wind. I know it has wide explosive limits but it would still seem a bit strange.

  42. phil_b says:

    In the 70s we ran urinary oestriol assays using a version of Kober reagent comprising mostly conc sulphuric and trichloroacetic acids. For extra nastiness the mixture was pumped through an oil bath at 120 Celsius. The back pressure would quite frequently cause the pump tubes to pop off their connectors and flail, and the reagent would spray around. I had several pairs of jeans decorated with multiple lines of holes, that appeared after washing.

  43. Scott says:

    I’m very late to reply, but one reason you wouldn’t want PTFE labcoats is that PTFE will melt into your skin, given enough heat.

    It’s why I wear cotton clothes at one place I work, the disabled guy I take care of like to throw pots around when he gets mad. Luckily, he hasn’t thrown a pot full of hot cooking oil at me. Yet.

    Otherwise, I wear lots and lots of Under Armour polyester shirts because they last far longer than plain cotton.

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