Stank

April 22nd, 2009 by excimer

Carbon disulfide, or CS2 (or commonly in my lab, “what the hell is that smell”) is a low-boiling organic solvent. Structurally, it looks just like carbon dioxide but with sulfur instead of oxygen. It’s used most often for Friedel-Crafts and related reactions, and for these reactions, there is no better solvent: for some reason, CS2 just works wonders.

It also smells fucking awful.

Well, sort of. CS2 in and of itself doesn’t have much of an odor, but there’s usually always a little bit of carbonyl sulfide, or O=C=S, in it. Doesn’t take much of COS to really pack a horrid punch, though. I have heard it compared to rotting pumpkins, but that’s too nice, I think- too reminiscent of life and happy things like halloween. I like to think of it as how Hell itself smells- decaying, tortured souls rotting in eternity for the mortal sins they committed, the odors of their lives of filth concentrated by the multitudes of the damned collected in its infernal realm. Not a fan.

So CS2 with its hick-ass cousin COS (if I made a Keeping Up Appearances reference here, would anyone get it?) is my least favorite commonly-used organic reagent. Now, of course, one’s opinion of smell is entirely subjective. Regardless, anyone who disagrees with me about this is wrong. Here’s some more smelly crap that I hate:

Pyridine
I don’t think most amines are that bad. Triethylamine and other amines like it smell like fish- not horrible, but not great by any means. Piperidine smells like semen for some reason, so I’m rather ambivalent about that one. But good lord I hate the smell of pyridine. Smells like concentrated vomit mixed with moldy bread.

Triethyl phosphite
This stuff just knocks you off your feet- it’s potent. I had to distill it one time and the smell just doesn’t go away- I smelled it for like an hour afterward. Gross.

Volatile Silanes
Chlorosilanes smell like burning, mostly because it reacts with water immediately to form HCl and silanol (or polysiloxane). So what you’re smelling is, in fact, burning. However, most volatile silanes smell pretty awful. Trimethylsilyl acetylene smells particularly weird- it’s oddly pleasant and gross at the same time. You want to like how it smells, but you just can’t.

Dimethyl sulfide
This is the reason people hate you for doing Swern reactions. Hint: bleach kills dimethyl sulfide. Fucking use it.

Anything with selenium
Selenium dioxide, phenylselenium bromide, selenides, doesn’t matter. They all smell like burning dog shit.

THF
THF is the world’s greatest solvent. It dissolves lots of organics, it has a relatively low boiling point, and it’s just useful in so many applications. However, it smells like stale urine.

Sodium cyanoborohydride
A must for reductive aminations, sodium cyanoborohydride’s the only salt on this list, but it’s here for good reason. It’s deeesgusting. And it lingers, especially around the balance you weighed it on.

Phenylacetylene
Smells like a mix of gasoline, rubber cement, and certain types of cheeses. Attacks your nose with fury.

2,3-butanedione
Strongly smells like buttered popcorn, a sort of eau de Orville Reddenbacher. But it’s also really potent; it lingers and makes you sick to your stomach in no time.

Cycloalkenes
It’s safe to say most cycloalkenes love to fuck with your smell receptors since they’re so close to delicious-smelling (and tasting!) natural products like limonene and pinene. One of our labs does a lot of ROMP. The smell of norbornene and dicyclopentadiene, the two most common ROMP monomers, is totally gag-worthy and does not go away; god help you if you spill it on yourself. Most of those conformationally-restricted cycloalkenes smell terrible: 1,5-cyclooctadiene (not-so-affectionally known as COD), norbornene, DCPD, cyclooctene… but I gotta say, bad as those are, none of them are as bad as norbornadiene, which will make you fear the wrath of God.

The list is by no means exhaustive, but if you think any of the above smell good, you’re insane. Now, there are a whole bevy of good-smelling things in the lab, but these tend to be even more controversial. I, for one, love most aromatic aldehydes (benzaldehyde, cinnamaldehyde, or my favorite, vanillin), toluene, and benzene (though I try to not inhale that stuff if I can help it). Feel free to include your own.

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79 Comments »

Comment by joel
2009-04-22 15:02:07

I totally agree with phenylacetylene (and its cousin styrene). Bleeeegh.

My favourite solvent to smell is methyl isobutyl ketone. Mmmm, whiteboard markers.

I worked with some straight chain aldehydes that made the whole floor smell like wet dog food. It made me want to drink bleach.

 
Comment by Aonmous
2009-04-22 15:06:29

I like phenylacetylene, and most alkynes too.

Organometallic chemists get the smelliest stuff – PMe3 is quite nasty, but I agree that phosphites generally smell worst. However PPhMeEt stinks

I like the smell of phosphaalkynes (thats P(trplbond)CR.

The worst smelling stuff is PPhMeH. I always think of phosphines as smelling like rotting sweaty undergraduates, x 100.

 
Comment by Aonmous
2009-04-22 15:07:37

oh, triethylborane – it doesn’t smell that bad at first but it really gets to you after 10-20 minutes, ending up with a stonking headache.

 
Comment by Noel
2009-04-22 15:15:34

I actually think TMS acetylene is tolerable. There’s definitely something more potent smelling in the lab. On the other hand, ethyl acetate is the little pleasure within common solvents.

 
Comment by Doug
2009-04-22 15:44:15

It’s pronounced “bouquet” not “bucket”. Seems doubly appropriate since you’re talking about hick cousins as well as smells.

 
Comment by psi*psi
2009-04-22 15:50:14

call me weird, but i LOVE the smell of TMS acetylene (and TES, and TIPS, and the list goes on…) 4,5-dimethylthiazole also smells like happiness to me. not sure why. ether, of course, is also awesome. i don’t like EtOAc nearly as much–fine in low concentrations, but too much of it and i definitely get a headache.

chlorosilanes aren’t all that bad–they smell like burning but don’t really get to me.

dimethyl sulfide actually makes me nauseous, which really sucks because my labmates do a lot of Swerns.

Comment by excimer
2009-04-22 17:16:57

TBS-Cl smells awful.

Comment by Hap
2009-04-23 11:47:16

I thought the hydrolysis product (TBS-OH) smelled like menthol.

 
 
Comment by Chemjobber
2009-04-22 20:13:24

Yeah, that stuff (TMS-acetylene) does smell pretty good.

Comment by Rhenium
2009-04-23 14:26:31

A whiff of TMS-acetylene takes me back to grad school in the blink of an eye… *sigh*

 
Comment by milkshake
2009-04-23 14:37:33

TMS acetylene smells good but I used this stuff to make 3-exo-methylene-1-methyl-1-propinyl-cyclohexane. This acetylene smelled awesome, like a skin of ripe mango, very warm, pine-and-fruit combo

 
 
 
Comment by Mike
2009-04-22 16:10:35

Cyclooctadiene and Cyclooctene: If they weren’t so useful for organometallic complexes, I’d stay faaar away from these.

1,1-Substitued Allenes: Smells like rotting meat and dog food at the same time. On top of that, they’re really volatile. Rotovapping on an ice bath anyone?

I do like the smell of ethyl acetate (apples!) and the terpenes my labmates worked with (geraniol, farnesol, nerol).

Comment by excimer
2009-04-22 17:02:35

how could I have possibly forgotten fused bicyclics? I shall add them.

Comment by milkshake
2009-04-23 12:44:53

THF to me smells like horse stables

Norbornadiene it not that terrible when diluted million times. I am doing some asymmetric hydrogenations these days and when I combine the phosphine with [Rh(NBD)2}BF4 and bubble argon through the mix, the scent of free norbonrnadiene is coming out, even with 2 mg of the complex. Flavor-vise it is not that different from cyclopentadiene. All pi bonds and lone electron pairs are smelly.

My favorite reek is trimethyl amine – it is the actual smell of unwashed privates. The parent amine is of course a gas but is salts are rather smelly too and do not evaporate so easily, instead they gradually hydrolyze on air and generate trace quantities of the amine – which is perfectly enough to make you an outcast. I used to work with hundred gram quantities of Me3N.HCl (the complex of this salt with two equivalents of AlCl3 is a potent stuff for cleaving OMe aryl ethers). The problem is when you spill little Me3N.HCl around the balances or on the floor, the dust gets soggy and melts and becomes invisible, and over the time the lab and all its inhabitants became scented like a neglected public urinal.

For the pervy readers here, i suggest combining trimethylamine with a hint of pyrrolidine. But don’t put it in your eyes – it probably burns like the real thing..

Comment by Hap
2009-04-23 15:50:30

The Larry Craig air freshener?

 
 
 
 
Comment by hegemon359
2009-04-22 16:46:00

I kind of like the smell of Cp (diluted, like opening a jar of ferrocene), it smells like wet dirt or something.

I may be strange, but PMe3 doesn’t really bother me as much as everyone else.

another nasty-gym-socks smell is small molecule shit with pivalyl groups like hexamethylacetone, pivaldehyde, etc.

 
Comment by davejac
2009-04-22 17:06:54

Thioacetic acid and Phenylselenium Bromide. I hate them forever.

 
Comment by excimer
2009-04-22 17:27:51

I think DABCO smells like peanut butter. Or is it just me?

Comment by ericthesalmon
2009-05-19 23:48:48

I’ll back you up on that.
Peanut butter, with a bit of the standard amine fishiness underneath.

 
 
Comment by Ψ*Ψ
2009-04-22 18:07:29

ooh, forgot: tributyltin(anything). i’m not really a fan of the smell of burnt hair

 
Comment by Will
2009-04-22 19:49:26

As an undergrad, I was in a lab that worked with a lot of thiols. A mistake or two later, and I don’t have too much of a sense of smell anymore.

It’s okay though because I can still smell things that smell good, just not things that a lot of things that smell bad; could be much worse.

Now my lab works with selenides, so not being able to smell has it’s up moments. However, even before my nose died, I use to somewhat enjoy the smell of triethylamine and pyridine, I guess I’m just weird.

 
Comment by Chemjobber
2009-04-22 20:14:23

Does anyone think catecholborane smells like ham? (or cured meats in general?)

 
Comment by unbalanced reaction
2009-04-22 23:07:25

You crazy (smelly) synthetic chemists!

 
Comment by Dood
2009-04-23 01:27:31

I spilled severlel mL of dicyclopentadiene once. Argh, the smell!

 
Comment by Andrew
2009-04-23 03:04:35

We have a bottle lf Aldrich P(OEt)3 labelled as triethyl phopshite. I always like to think someone was being a litle mischeivous on a Friday afternoon as opposed to genuine typo!

 
Comment by Davis
2009-04-23 08:40:28

Sulfur compounds:
Lawesson’s reagent.
Ethanedithiol.

Others:
Isovaleraldehyde – smells like sweaty socks.

 
Comment by Hap
2009-04-23 08:58:14

1) CS2 is pretty toxic and has a really low flash point (I think it can be ignited by steam baths) – just some bonuses.

2) The alleged pyridine-impotence thing probably affects my opinion of it, but the smell is noxious, anyway.

3) Butanedione isn’t so good anyway – cancer + icky butter smell = bad. Whenever someone in the department microwave popcorn, it’s like a pheromone for demons.

4) Amyl nitrite smells like dirty socks steeped in gick and left in a car for about a month. If you need it for…recreational purposes, I’m so sorry.

5) Phenylphosphine. One of the people I knew in another lab worked with it, and even in a hood, with thick gloves and a lab coat he could smell it when he went to sleep. It smells like mesityl oxide with hellacious staying power.

6) Thioacetic acid is noxious. So is Me2S. No one in my lab did Swerns, but they did thioacetic acid thiolations all the time.

 
Comment by Lucas
2009-04-23 10:36:05

My uncle is a funeral director in the midwest, and once while visiting I had the dubious honor of riding in a hearse to pick up a body that had been lying in a Missouri backwater for two weeks (in midsummer, no less).

Fifteen years later, CS2 (or rather, it’s friend COS) is the only smell I’ve found that compares. In fact, COS goes further – I think that if you take that lovely aroma of decay, mix it up with the worst farts you can imagine, and light it all on fire, that’ll approximate the smell of COS.

Also, piperidine – I’m glad I’m not the only one. I could never quite come out and ask.

And I wouldn’t say I *like* pyridine and THF, but I’ve come to find them relatively inoffensive, and they each have some pleasant associations.

Comment by Ψ*Ψ
2009-04-23 12:45:18

I associate THF with its horrible smell, the burning sensation when a little of it spills onto my gloves, the pain in the ass of repeated extractions to get it out of solution…none of which is pleasant. I actually go out of my way to avoid using it most of the time.

 
 
Comment by Uncle Al
2009-04-23 11:45:05

We tried to improve a pot of “clean” CS2 by slowly distilling it through a column loosely packed with bright copper wool to grab sulfurous species (hood!). OTOH the middle cut was water white wth a mild fruity scent. OTOH, the next day the liquid was purple sitting in its roundbottom. This is one of the great unsolved mysteries of chemistry. Its pursuit deserves massive TARP funding.

 
Comment by Uncle Al
2009-04-23 12:00:49

US Pat. 5973183, abstract: “yields exceeding 100% tetraphenoxymethane are observed” How cool is that, CS2-wise?

 
Comment by Shmoppy
2009-04-23 12:14:26

I’ve always thought of the smell of pyridine as dead, rotting cake. If cake could die, anyways.

Comment by excimer
2009-04-24 00:08:40

cake or death!

Comment by Hap
2009-04-24 15:33:12

why not both?

Maybe it’s just me, but Cake could also die, or at least I don’t need to hear from them again.

Comment by excimer
2009-04-24 16:03:21

eddie izzard fail

Comment by Hap
2009-04-24 16:11:00

huh?

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Comment by psi*psi
2009-04-24 17:04:31

really? you’d pick death over cake?

 
Comment by Hap
2009-04-24 17:22:24

I didn’t get the Izzard fail. cake over death yes. Cake over death…I’d have to think about it.

 
 
Comment by excimer
2009-04-24 19:22:23
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Comment by Stephen
2009-04-23 12:50:29

2′-methoxy acetophenone smells like leather

Comment by milkshake
2009-04-23 13:21:55

sprinkle it on a friend, then call him a leather-daddy

Comment by Ψ*Ψ
2009-04-23 18:54:02

did someone say leather daddy?

Leather+Daddy.jpg

Comment by excimer
2009-04-24 00:08:26

wow, david cross looks way too much like nicolaou in that picture. or rather, some mix of nicolaou and one of the village people.

Comment by Adam Man
2009-04-24 09:09:34

That’s interesting, because the first thing I thought when I met Nicolaou last year was ” he should be in the Village People”

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Comment by milkshake
2009-04-24 12:42:06

So you are basically sayin’ its not KCN in that picture?

 
 
 
 
 
 
Comment by Hap
2009-04-23 13:43:50

OT: I saw a bumper sticker that PP* would have loved: WWACD: What Would Ann Coulter Do? Other than the fact that the person with the bumper sticker obviously has had an overly successful lobotomy if asking what Ann Coulter would do could actually gain them anything useful, I think if the answer wasn’t “roll myself in napalm mixed with rust and aluminum powder and then set off some backyard fireworks with a leaky blowtorch”, they need to ask again.

Comment by psi*psi
2009-04-23 15:26:35

I wish someone would give Coulter a lobotomy. Or set her on fire. Or see if she dissolves in conc sulfuric. I’m not picky ;)

Comment by Hap
2009-04-23 15:48:18

Swallowing hot lead would also be appropriate, though way too remniscient of the martyrdom of early Christians to avoid notice. She dishes out enough, after all. She’s already had a lobotomy, though (or she doesn’t need one) – maybe you mean a laryngectomy?

I want entertainment from her demise, and I want to make sure that resurrection is not a physical possibility. Saddling her to a portable nuke on an isolated Pacific Ocean atoll would also work as long as there were cameras to make sure that she was still present when the device detonates. Barring that, I’ve always wanted to see a themite reaction. Two birds with one stone.

Bumper stickers are nice ways to tell that a Columbus driver is a self-identified brain donor ["Bush/Cheney '04" (yes, I was stupid enough to vote for them twice) and "WWACD..." (if AC could contribute to your body of knowledge, then your IQ is probably an imaginary number)]. The problem is, if driving while stupid were a crime, at least half of Columbus couldn’t get to work.

Comment by milkshake
2009-04-23 15:55:11

you are all to bloodthirsty. I would just sell her to the pirates.

Comment by Hap
2009-04-23 16:05:52

Sorry – I don’t want her coming back. Besides, what makes you think the pirates would want her? The old joke about sharks not eating her out of professional courtesy comes to mind.

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Comment by milkshake
2009-04-23 19:23:04

I think they pirates would fucking worship her. The toxic waste is best dumped at the opposite hemisphere

 
 
 
 
 
 
Comment by Wavefunction
2009-04-23 13:54:48

Doesn’t pyridine cause impotence or similar stuff? Also, I had a vial of DMS during my 2nd year literature seminar, ensuring that the Q & A session would be terse and short. Interestingly I was demonstrating the very curious difference in smell between DMS and DMS-d6 which was cited as support for a novel theory of smell by Luca Turin based on vibrations of bonds.

Comment by Rhenium
2009-04-23 14:29:26

So, what is the difference in smell?

Comment by Wavefunction
2009-04-23 16:31:01

DMS-d6 smells a little more “sweetish”. To my knowledge none of the existing smell theories can explain this well.

 
 
Comment by Chemjobber
2009-04-23 20:03:51

I think the “pyridine = impotence or sterility” is probably the number one organic chemistry urban legend. There’s relatively little in the literature about it (the reproductive toxicity), but the stuff is pretty awful for the liver.

 
 
Comment by Rob W.
2009-04-23 14:52:05

Best smelling solvent: butyl acetate. It’s like synthesizing a delicious piece of banana Laffy Taffy.

Comment by excimer
2009-04-23 16:25:16

all of the long-chain alkyl acetates smell awesome. hexyl acetate is also yummy

 
 
Comment by lab_rat
2009-04-23 19:58:38

hexamethyldisilathane (aka Bis(trimethylsilyl) sulfide)… used it in grad school to make CdSe/ZnS core/shell nanoparticles. The nastiest thing that I’ve used. I would open the antechamber to the glove box and dunk all exposed syringes/pipets/vials into bleach as fast I as could. It helped, but 5 minutes later, everyone on the floor knew that I was making nanoparticles that day – and they weren’t too pleased with me.

 
Comment by cowzzwoc
2009-04-23 21:02:55

O come on! No one has mentioned Butanoic acid! That stuff smeels like someone just vomited all over you

 
Comment by SiO2 lungs
2009-04-24 03:42:41

I obviously like silanes (excluding chlorosilanes though). Love Et2O and benzoic acid, benzene + lots of aldehydes : )

To me it’s incredible how a C-C bond can make such a difference. Hate THF smell.

Pyridine sucks too.

I remember smelling a 4L bottle of concentrated aq ammonia, as undergrate. I was such a fool!

Comment by Hetero D-A
2009-04-25 02:22:00

I’m involved in our saacs club, and we do demo’s. The one thing worse than con ammonia? The straight gas. We used it for a few demos, and one time i got a full blast of it. Oh, the burning! I think i had a head cold for the rest of the week.

 
 
Comment by Uncle Al
2009-04-24 11:50:00

E,E-Farnesaldehyde! The nitrile is almost as good and much less air-sensitive. Then industrial chemists get hold of it, US pat 7342042.

 
Comment by Abid
2009-04-25 14:39:52

HEXYL ACETATE BITCHES

that shite smells amazing.

 
Comment by cientificorojo
2009-04-25 16:28:19

I haven’t used piperidine yet, so I can’t attest to its semen-like smell. Hexane-1,6-diamine, on the other hand … smells eerily similar to semen.

Comment by Hap
2009-04-25 20:44:57

I think spermine has a similar structure – cadaverine is in the same ballpark as well (H2N(CH2)5NH2?)

Comment by excimer
2009-04-25 23:42:55
Comment by milkshake
2009-04-26 16:46:36

growing crystals of natural spermine phosphate would be a perfect fraternity experiment

Comment by Hap
2009-04-27 08:28:44

anything that takes time from drinking to excess and attempting to bed young sorority women is probably verboten.

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Comment by Wavefunction
2009-04-27 13:23:26

In fact the frat boys could use their own sperm to do this?

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Comment by Hap
2009-04-27 07:28:24

oops.

 
 
 
 
Comment by kenny
2009-04-25 23:04:06

NaSMe.

Boy did I make some enemies with that shit.

Comment by milkshake
2009-04-26 16:50:28

MeSH is for wimps. EtSH is incomparably stronger and more fecal.
I did a Me-thioester preparation few times where I generated ketene enolate by acetylide oxidation with tBuOOLi and then I quenched by condensing several mL of MeSH into the mix.

Comment by j.
2009-04-27 01:47:27

EtSH is awful! I’ve used THF, pyridine, DMS, and phenylacetylene. None of them are even in the same league as EtSH. For that matter, THF and DMS aren’t in the same league.

We should have a log scale of stank.

 
 
 
Comment by Chemoptoplex
2009-04-27 10:53:21

I’ve used way too much thiophenol, bleach is my friend. Oddly, 2-mercaptopyridine which you would think would be the heinous hell child of two infamous stinks is practically odorless. It has a faint garlicky odor, but if someone opened a jar of it next to you, you’d probably never even know.

Comment by milkshake
2009-04-27 11:00:29

its because it exists mostly as the tautomeric 2-thiopyridone, and it is a crystalline solid too – with mp 130C – so the vapor tension is pretty low

Comment by carbn
2010-05-30 10:31:21

Anyone smelled THT (tetrahydrothiophene)? One of our postdocs had the marvellous idea to use it as a solvent for Au anions a year or so ago. It needed to be distilled over Na for 3 days to dry it, during which time just about everyone on the floor complained about the unholy smell (despite it being properly in a fumehood).

In the end, we only used about 20 mL of the 2 litres or so we distilled. This went into its own special waste container that we got round to getting rid of a month or so ago. Actually disposing of the solvents was unremarkable (except for the smell…, and having to bin my labcoat that I spilled a *tiny* amount on), but the container was rinsed out by filling it with water twice, acetone, the contents of our normal solvent waste, and our chlorinated waste. It still smells so bad that we can’t take it out of the cupboard without the lab instantly smelling of THT.

The remnants sit in sealed ampoules. My supervisor has just asked me to get rid of it this week :( .

 
 
 
Comment by Hamish
2009-04-28 00:05:46

Excellent :D I’m so glad I’m not the only one who thinks piperidine smells like jizz. Haha. I also agree wholeheartedly about pyridine – it’s RANK…..

As for the good smells…. diethyl ether…. MMMMmmmm, and toluene is yummy too. I don’t mind acetone either, considering i practically bath in the stuff when I do a lot of my washing up :)

 
Comment by Denise
2009-04-28 00:46:10

Pyridine smells like a whiff of chocolate chip cookies followed immediately by a sucker-punch of extreme nausea. I loathe it. I’d rather have the NEt3 or some such which while pungent does not taunt me with the whiff of something delicious.

I also believe the hydrolysis product of tert-butyldimethylsilyl chloride smells like rotting cabbage.

I think the food- and ex-food smells hit me harder than the other noxious smells. I’m counting methyl mercaptan as an ex-food smell. I swear I can produce it under exactly the wrong intestinal circumstances.

 
Comment by LiqC
2009-05-05 16:40:16

I LOVE C7-C10 straight-chain alkanes. Hexane smell is too weak. Undecane is already too much on the kerosene side. But heptane through decane are awesome.

I heard somewhere that it is not alkanes that we smell but rather the trace amounts of corresponding alkenes. Don’t quote me on that.

 
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