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Things I Won't Work With

Things I Won’t Work WIth: Thioacetone

My recent entries in this category have, for the most part, been hazardous in a direct (not to say crude, or even vulgar) manner. These are compounds that explode with bizarre violence even in laughably small amounts, leaving ruined equipment and shattered nerves in their wake. No, I will not work with such.
But today’s compound makes no noise and leaves no wreckage. It merely stinks. But it does so relentlessly and unbearably. It makes innocent downwind pedestrians stagger, clutch their stomachs, and flee in terror. It reeks to a degree that makes people suspect evil supernatural forces. It is thioacetone.
Or something close to it, anyway. All we know for sure is that thioacetone doesn’t like to exist as a free compound – it’s usually tied up in a cyclic thioketal trimer, when it’s around at all. Attempts to crack this to thioacetone monomer itself have been made – ah, but that’s when people start diving out of windows and vomiting into wastebaskets, so the quality of the data starts to deteriorate. No one’s quite sure what the actual odorant is (perhaps the gem-dimercaptan?) And no one seems to have much desire to find out, either.
There are sound historical reasons for this reluctance. The canonical example (Chemische Berichte 1889, 2593) is the early work in the German city of Freiburg in 1889 (see here), which quotes the first-hand report. This reaction produced“an offensive smell which spread rapidly over a great area of the town causing fainting, vomiting and a panic evacuation.”. An 1890 report from the Whitehall Soap Works in Leeds refers to the odor as “fearful”, and if you could smell anything through the ambient conditions in a Leeds soap factory in 1890, it must have been.
The compound shows up sporadically in the literature until the mid-1960s, when several groups looked into thioketones as sources of new polymers. The most in-depth analysis took place at the Esso Research Station in Abingdon, UK, where Victor Burnop and Kenneth Latham got to experience the Freiburg Horror for themselves:

“Recently we found ourselves with an odour problem beyond our worst expectations. During early experiments, a stopper jumped from a bottle of residues, and, although replaced at once, resulted in an immediate complaint of nausea and sickness from colleagues working in a building two hundred yards away. Two of our chemists who had done no more than investigate the cracking of minute amounts of trithioacetone found themselves the object of hostile stares in a restaurant and suffered the humiliation of having a waitress spray the area around them with a deodorant. The odours defied the expected effects of dilution since workers in the laboratory did not find the odours intolerable … and genuinely denied responsibility since they were working in closed systems. To convince them otherwise, they were dispersed with other observers around the laboratory, at distances up to a quarter of a mile, and one drop of either acetone gem-dithiol or the mother liquors from crude trithioacetone crystallisations were placed on a watch glass in a fume cupboard. The odour was detected downwind in seconds.”

Now that’s a compound to be taken seriously. How do you work with something that smells like hell’s dumpster? Like this:

“The offensive odors released by cracking trithioacetone to prepare linear poly(thioacetone) are confined and eliminated by working in a large glove box with an alkaline permanganate seal, decontaminating all apparatus with alkaline permanganate, eliminating obnoxious vapors with nitrous fumes generated by a few grams of Cu in HNO3, and destroying all residues by running them into the center of a wood fire in a brazier.”

So there you have it – just install a fireplace next to your hood (what every lab needs, for sure) and remember that, in a thioacetone situation, fogging the area with brown nitrogen oxide fumes will actually improve the air. (This is from Chemistry and Industry, 1967, p. 1430, if you need more details, and I hope you don’t).

44 comments on “Things I Won’t Work WIth: Thioacetone”

  1. Sili says:

    Freiburg! Of course. I’d forgotten the name of the city.
    My org chem lecturer loved to tell stories like that. He’s a sulfur chemist himself, so he had plenty of those stories. And of course the founder of the field was a Dane.
    I think Zeise was thrown out of the theatre once, and his landlady wanted to evict him for keeping cats – she thought.
    If I were a better chemist, myself, I’d rather like to contribute something on the structure of stuff like this. Good thing I’m not, I guess.

  2. Alex says:

    Would it be possible to make this blog searchable so previous post could be retrieved quickly using search terms? I for one would greatly appreciate it.

  3. Chemoptoplex says:

    So how about the selenoacetone?

  4. Muruga says:

    In general, it will be a good idea to treat the volatile thio /organosulphur compounds with respect. They tend to have the characteristics of unpleasant odour and are suspected to be toxic.
    Examples include carbon disulphide, dimethyl sulphide, methyl mercaptan & ethyl mercaptan.

  5. RB Woodweird says:

    On the other hand, “Hell’s Dumpster” would be a pisser name for a band.

  6. Norepi says:

    What’s most impressive about this is that they had to use permanganate to decontaminate the vile stuff. Won’t bleach work well enough? My current synthesis has two stinky steps back-to-back (one rxn employs dimethyl sulfide, one produces it); I keep an aerosol bottle of bleach around to spritz everything with after!
    We had a post-doc in our group a while back who was making various thioacetals and thioketals as part of a hydroxyl -> mercaptan switch (or something of the sort) for some SAR study. Everything stunk, including him, but his olfactories were fricasseed from using the stuff for too long, so he wasn’t aware of it. He would go to seminars and people two rows behind him would complain, usually with insulting remarks about the guy’s personal hygiene.
    The sulfur chemistry is no more, but the guy’s corner of the lab has a permanent stench.

  7. This reminds me of a conversation between Matt Meselson and Linus Pauling:
    LP: Well, Matt, you know about tellurium, the group VI element below selenium in the periodic chart of the elements?
    MM: Uh, yes. Sulfur, selenium, tellurium …
    LP: I know that you know how bad hydrogen sulfide smells. Have you ever smelled hydrogen selenide?
    MM: No, I never have.
    LP: Well, it smells much worse than hydrogen sulfide.
    MM: I see.
    LP: Now, Matt, Hydrogen telluride smells as much worse than hydrogen selenide as hydrogen selenide does compared to hydrogen sulfide.
    MM: Ahh …
    LP: In fact, Matt, some chemists were not careful when working with tellurium compounds, and they acquired a condition known as “tellurium breath.” As a result, they have become isolated from society. Some have even committed suicide.
    MM: Oh.
    LP: But Matt, I’m sure that you would be careful. Why don’t you think it over and let me know if you would like to work on the structure of some tellurium compounds?

  8. milkshake says:

    I think I was the original report on lamentable effects of diethyltellurium exposure – that caused the unfortunate chemist smell like rotten corpse, for about one year after he stopped working with the substance, and turned him into a celibate outcast. This report alone discouraged further inquiries into the organotellurium chemistry for the next half century. Only later it was found that Te(IV)-organo-halogencompounds are well behaved and practically odorless.

  9. Larry says:

    I prepared a series of S-Me…Bu herbicide derivatives from the thiols and took all possible precautions–hood, gloves and bleach bottle. Nevertheless, the vapors still escaped. In contrast, many don’t realize that it’s only the very low MW S-compounds that are offensive. Organosulfur compounds have such a synthetically useful oxidation state range.

  10. partial agonist says:

    I “just say no” to all sulfur chemistry in med chem compounds unless the sulfur atoms are in a heteroaromatic ring or in an aryl thioether linkage (and even the last one I’d not be too happy about). No alkyl thioethers, thiones, thioamides, thioureas, etc. Now, thiazoles and benzothiophenes are OK, for sure, and other such beasties.
    I’m probably bypassing things that did some good somewhere, but I don’t want to smell it being made or worry about the metabolic fate of the sulfur.

  11. Ralph says:

    Hey, another 16,000 pharma people lost their jobs!
    I think derek will need to translate this blog into Chinese.

  12. partial agonist says:

    oops… I shouldn’t exclude the perfectly fine sulfonamides and some sulfones. I’ll still take a pass on sulfoxides, thioureas, and such
    “Properly oxididized” and a little sulfur goes a long way!

  13. Alig says:

    “I’ll still take a pass on sulfoxides”
    So you wouldn’t have made prilosec? It was only the best selling drug in the world for several years.

  14. Hap says:

    My advisor’s group made lots of thiols – with relatively long alkyl groups, they aren’t that stinky (reminiscent of oil refineries, but not very penetrating or persistent). The thioacetic acid used to make them, on the other hand, isn’t terribly pleasant.
    Selenoketones must be oh, so yummy.

  15. CMCguy says:

    This topic connects to the Random Questions #1 in that some people after saying it was their hardest subject will add “they hated the smell in labs”. If they only knew how bad it could get.
    I worked with a few bad smelling sulphur compounds/reactions (nothing as intense as thioacetone) but must have built up a tolerance/overwhelmed my nose that it did not bother me yet my wife always knew if I had been doing such chemistry that day. Even so I could still catch the smell the phosphine compound work from another lab which made me ill.

  16. Metaphysician says:

    #15- I thought any detectable level of airborn phosphine was cause for evacuating the premises? Or was the smell from some less radically toxic reaction products?

  17. Hap says:

    I assume it’s a substituted phosphine, not phosphine itself. Some phosphines have really notable odor threshholds, and have really persistent odors as well. A grad student in one of the other labs worked with phenylphosphine for a while, and the odor (like a phosphorus version of mesityl oxide) was really persistent (he could smell it when he slept even though he wore lab gloves, coat, etc.) and gave at least one of the labmates headaches.

  18. Jan Teller Jr says:

    This post makes me think about the fact that having worked in phys, org and now at a inorganic chemistry lab is quite funny the concept of danger.
    For instance, whilst a Swern oxidation is a no-no reaction if you want to oxidise alcohols (at least here), SeO2 or CrO3-based reagents become the reagents of choice even at large scale.
    However, nickel and copper salts can be all over the place, just cause they dont smell, and hence, as it turns they are no toxic. Why occupying lab space with an evil machine such as a rotary evaporator when you can wait weeks for your ligand to crystallise.

  19. CMCguy says:

    #15 Metaphysican, #16 Hap is correct as if memory serves was alkyl and aryl derivatives involved, perhaps even alkyl or aryl phosphine oxides (although I seem to recall they did start with PH3 at times).
    #18 JTJr there is often a skewed sense of danger in scale-up with trade offs typically surrounding Control (both Safety issues and Reproducibility). I think Swern’s avoided due to DMS evolution (gas/low boiling liquid) and variability in yields/purities experienced. Waste streams are more considered than such used to be however immediate tox danger in the plant makes utility of “exotic reagents” (heavy metals/rare earths) less attractive (yet are examples of reactions done at tonnage levels to contradict this).

  20. Jan Teller Jr says:

    You are right, but my point was more related to the fact that sometimes people not familiarised with experimental orgchem as many inorganic fellas are, tend to correlate toxicity with odour (which sometimes actually is).
    Just to add that, I think you can do Swern oxidations at multigram scale (i.e. Smith III et al., althought I wouldnt think about that if I were a process guy as you pointed out.

  21. processchemist says:

    I actually performed a Swern oxidation in a 30 l reactor some years ago. It was not so tragic but: sistem vented to a scrubber with sodium hypochlorite, acqueos layers from the workup quenched directly in sodium hypochlorite etc etc etc.

  22. processchemist says:

    I actually performed a Swern oxidation in a 30 l reactor some years ago. It was not so tragic but: system vented to a scrubber with sodium hypochlorite, acqueos layers from the workup quenched directly in sodium hypochlorite etc etc etc.

  23. JH says:

    Having studied this particular subject, I have suspicions that the vile smelling compound they made first in Freiburg might actually be some sort of sulfur derivate of an acetone condensation product. The textbook in question gives a bit different picture compared to the actual Berichte article. They bubbled H2S and HCl through a mixture of acetone and ZnCl2. The ICI researchers from the 1960’s added that the mixture had to be cooled. I think the Germans then went on to distill and steam distill, when the horrible stink took over and the people from the neighbourhood got “restless” as it was reported, but still, no mention of an evacuation. They added that in their laboratory sulfur chemistry was everyday activity and thiols generally had no such effect on the general population.
    Following the idea of an acetone condensation product, I found mentions in the literature of mesityl oxide giving absolutely horrible stench when left in prolonged contact with animal proteins.
    One case was of a slaughterhouse where they had for some reason used a cleaning composition containing mesityl oxide, the other one was mesityl oxide containing plastic material used for a cheese wrapper.

  24. cookingwithsolvents says:

    I did some Te chemistry. It was cool stuff but the compounds were light sensitive, which is damn irritating to deal with. The good thing was they photoreduced to Te(O) so there was very little stink (even if the glassware was a pain to clean). One time I opened an nmr tube to dump it a few inches before I was in the hood. I nearly threw up right then and there. Ended up in the hallway, gagging. We had great hoods and the lights were on in the lab so by the time I recovered there actually was no stink. I can’t fathom working with Te compounds which didn’t have this neat little feature. . .

  25. Jose says:

    Co-workers and I named a nasty thiol “Satan’s Anus” at one point, but Hell’s Dumpster might beat that….

  26. Bored says:

    #5 RB Woodweird and #25 Jose: No, “Satan’s Anus” is by far the best name for a band, anywhere, any time. The name alone would guarantee a following, even if the band couldn’t play a note.

  27. ds says:

    I worked extensively with very volatile thiols (C2-SH to C5-SH) during graduate school. I never had a problem with their smell, although others complained!
    The only compound I avoided to work with was mercapto-isopropanol: I get a headache from smelling it.

  28. David P says:

    I have worked with quite a few sulfides over the years. The Swern oxidations were an interesting tale, as no one in our lab smelled anything, but the smell was going out the hoods and then getting sucked back in elsewhere in the building, with all the expected complaints.
    We also had a series of compounds to make all with disulfides (many made from the corresponding mercaptan). We did take quite extreme measures (gloves never left the hood area, Companion had a hood to itself, lots of bleach around) and never had any complaints (the air system must be better in that building 😉 ).
    And then there was the group downstairs working on tellurium compounds. Well, one chemist anyway. The loneliest chemist in the building…

  29. FMG says:

    #24 cookingwithsolvents: do you have a literature reference for these compounds? The description really caught my attention (and no, I am not planning to use them in any real-life nefarious scheme or prank). Thanks.

  30. Gerry says:

    Would it make some sense to mention common sources of Thioacetone, assuming there are any???

  31. Halogen Exchanger says:

    that reminds me of my accidental rinsing of that P4S10-contaminated flask with acetone. it might have produced quite a bit of thioacetone and made one of my colleagues walk out of the computer room 100 ft from the lab immediately, complaining about the odor. he quickly found me as the culprit since I was the only one doing sulfur chemistry at that time…
    and I got headache for 3 days thereafter.

  32. Johnny Stettin says:

    This entry reminded me of my early days a at pharmaceutical company (who shall remain nameless) in West London. My Barton Decarboxylation with tertbutyl mercaptan regularly evacuated the HQ building as the prevailing wind swept the fume hood stack vents in that direction. I, of course, smelt nothing. Finally the smell was traced to my fume hood…

  33. milkshake says:

    HAL-exchanger: Inspired by your instructive post I immediately set out to combine a spoon of P2S5 with few mL of acetone, and I heated it to reflux for few min and then I let it sit in a hood at room temp. Unfortunately there was no reek that could make the good German villagers restless, all I got was the eggy smell of H2S. After few hours of frequent smell inspection I could detect a faint mercaptan-like sweetish odour of something else in the background, but it was faint. One could hardly stink up a lab with a wimpy stuff like this one.

  34. Anonymous says:

    Well, our research group works with gold and surfaces, so we love alkyl thiols – from volatile 2-mercaptoethanol, up to C11 oils, and solid thiols, and some kinds of dithiols as well.
    The volatile ones are terrible, but the smells also go fairly quickly. The most terrible ones are the C8-C11 thiols. When they spilled onto lab coats, they tends to stick and smell like hell=.=
    Everytime a new research student come in, there’s a risk that they did not used bleach to clean the glassware, and just used acetone to wash. When this happens, we have to open the lab doors to force air in…

  35. szaleniec says:

    A memo went round the chemistry department of the major British university at which I work, banning all use of malodorous reagents during graduation week. This followed an incident last year, which can readily be imagined – I was on vacation at the time, but got the reports.

  36. Fawnet says:

    I have so much fun reading these posts. I know almost nothing about chemistry, but you have such a clear, clean writing style that I still understand, just from context.
    Thanks for an amusing read!

  37. Shii says:

    If you could mobilize this it would make a great harmless chemical weapon

  38. Scott Ager says:

    Just found this blog. What a hoot. Many years ago, a bunch of us undergrads cooked up a liter (yes, a liter. What did we know?) of n-butyl mercaptan one late night. Even though it was made in the fume hood, the entire building stank the next day. The “perps” were easily identified the next day by various students, staff, lab animals, and professors. Threatened with expulsion, we all apologized profusely but did not give up our weapons-grade material.
    Unfortunately, before the first sorority could be brought to its collective knees, a local dog dug up and looted our stash from it’s secure bunker 3 feet down in the dirt in the dorm’s back yard. Sigh. An acquired taste, mercaptans.

  39. Scott Ager says:

    #5, #25, #26 – Guys, where’s Johny Rotten? We need him now.

  40. Hal Crawford says:

    Shii, I was thinking along the same lines that this would be a great weapon – might have saved time smoking out Noriega during that siege in Panama. Not sure about calling it “harmless,” however….

  41. Philip says:

    Where is the bit about the panic evacuation from? It isn’t in the Chemische Berichte-article, I checked that one. The smell spread in a 750m radius, a couple people vomited or fainted, that’s it as far as that article is concerned. Also no other source in the pdf you linked, and I can’t seem to find out what book the pdf is from. I also can’t seem to find any other source in German for this, which makes me suspect that the tale has been exaggerated a bit over time. I’d head over to the University of Freiburg library and check the papers for 1889, but going through a year’s worth of newspaper on microfilm is not a pleasant prospect.

  42. Philip says:

    Whoops, make that a year’s worth of newspapers in pdfs.

  43. Derek Lowe says:

    Hmm – I never had that in my head as an evacuation of all of Freiburg, just the neighborhood where the thioacetone was making its presence known. But some people seem (over the years) to have decided that that’s what happened – that mistake seems to be all over the internet. Note this letter from an Australian chemist, who concurs with you that that would be a tale that’s grown in the telling.
    The book is this chemistry textbook from Oxford University Press

  44. JerryBear says:

    Greetings! I am a great aficionado of Durian fruit, which is famous for its pungent sulfur compounds. Either they smell unspeakably foul or alluringly savory. In my case, it smells sort of like a well ripened pail of dirty diapers for one to two minutes but then abruptly switches to an alluruing smell like onions fried until brown and crispy. I have noticed overtones of faint skunk and smoked oysters. Most of my friends cant get near it. One says it smells like vomit, another compares it to an open sewer. I buy my Durian fruit from an Oriental market, fresh frozen from Thailand. It has an intensely sweet, intensely aromatic creamy taste with complex savory overtones. It is my favorite fruit and I can see why people in SE Asia go into debt during Durian season. I cannot find any information identifying the sulfur compounds in it though. Maybe somebody here might be tempted and buy some to play with it, I do have some alcoholic extract of Durian fruit which might be more available and easier to analyze. I am not particularly bothered by sulfur compounds, Hydrogen sulfide has an odly appealing cabbagy smell to me and even hydrogen selenide seems more radishy than horrible to me. I have no desire to ever mess with tellurium!

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