Chemistry Blog



May 22

Nitroolefins – The Crying Game

by See Arr Oh | Categories: chemical education, chemical safety, lab technique, opinion | (68577 Views)

(This post was written for the ‘Toxic Chemicals’ carnival, over at ScienceGeist)

Let me tell you about the time I broke down crying in lab. No, it wasn’t an epic breakup, or even a death in the family. It was…a nitroolefin.

Many summers ago, I worked as a pharma intern, a small flywheel in a then-huge drugmaking machine. My supervisor, a kind, safety-conscious scientist, begged me to come straight to him if I had any questions about my reactions.

We were synthesizing a small nitroolefin – 2-nitropropene, to be exact – for some nitro-Michael additions. If you look at the Org. Syn. prep, it warns, right at the top in red letters, that the compound is a potent lachrymator. The term, from the Latin word for “teardrop,” describes compounds that irritate the eyes to such an extent that tears freely flow.

I carefully piloted the reaction, distilled the greenish-yellow product, and then watched it run up my TLC plate. Beautiful! Now, I just needed an NMR sample.

Gingerly, I dissolved a drop into some chloroform. Forgetting for an instant, I pulled the NMR tube out of the hood to cap it, and within seconds crumpled to the bench. It felt as if someone had stabbed smoldering iron toothpicks into my eyes. I stumbled around until my labmates dragged me over to the eyewash; later, I became well acquainted with our local safety officer. My eyes remained bloodshot for the rest of the day. Lesson learned: Lachrymators are not to be taken lightly! (I’ve experienced similar, though milder, reactions to benzyl bromide and thionyl chloride).

For those younger chemists thinking about summer lab work, take a few minutes to find out if your reagents might cause uncontrollable crying. Cautious handling, and a well-fit respirator, can go a long way towards your future safety and comfort.


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  1. opsomath

    I was sitting at my in-lab desk in grad school, and kept having to wipe my eyes. Ow. Is something wrong with me? Do I need to go to the health center?

    Then I heard our new first-year grad student’s little voice. “What’s ‘lachrymator’ mean?” She was reading the bottle, having just been dispensing some kind of alpha-bromo carbonyl thingy out on the bench with no ventilation. Her eyes were watering too.

    I explained, with a certain amount of profanity and hustling to the fume hood with the bottle, what that little bit of vocab meant.

  2. Free Radical

    I’m giving my org chem final exam tomorrow. I fear it may be a lachrymator.

  3. See Arr Oh

    I need to reinstall my “Instant Rim-shot” button on this blog, permanently! 🙂

  4. Anonymoose

    I got an accidental whiff of benzyl chloride outside of the hood, and that made my eyes sting for half an hour.

  5. lots

    Ah! This post takes me back to my first year organic chemistry labs. The instructions warned us in bold that the product was a lachrymator, but I think (like opsomath’s first year student above) few of us knew what it meant. Crying ensued.

  6. Fleaker

    You know, I think it’s mixing the lachrymator with a solvent that makes it far worse than normal.

    Want to know suffering? Wait til a grad student makes the mistake of putting a flask that they *thought* was rinsed free of benzyl chloride in the hot glassware dishwasher. Yarkes!

  7. Chemist

    Have quite some experience with nitroolefins.
    You may have been lucky with your distillation. These compounds are very potent explosives. You did it under vaccum?

  1. Toxic Carnival: Day Two | ScienceGeist

    […] today and is making the rest of us look bad for our lack of productivity! In the post, See Arr Oh discusses crying in lab. The tears in this case were due to 2-nitropropene. A quick minute outside of the hood in an […]

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