Sciencemadness Discussion Board

How bad does Indole smell?

Electra - 5-5-2016 at 11:36

In small amounts it has a flowery smell but in high concentrations I've read it smells like feces. I've even read some reports that it can stink up the entire room and outside the building. How bad can it be? I wanted to get some but am starting to be afraid of the possible odor.

[Edited on 5-5-2016 by Electra]

aga - 5-5-2016 at 11:37

There really is only 1 way to find out.

myristicinaldehyde - 5-5-2016 at 11:53

Stick your nose deep into something with that "white flower smell". You can already detect the fecal aspects then! It's potent stuff.

UC235 - 5-5-2016 at 12:51

Having actually smelled reagent grade indole, it doesn't smell like much. I'm not sure where the wealth of misinformation comes from. It's like slightly funkier naphthalene. A bit fecal, a bit animalic, mostly PAH. Possibly skatole is much worse, but I don't have experience with that compound.

DJF90 - 5-5-2016 at 13:23

I use variously substituted indole boronic esters on a regular basis for work. They do have a peculiar smell (which may be partly attributable to the ester), but its not excessively pungent and I wouldn't worry about using them in an independent setting. I've nkt had the pleasure of working with plain old indole before, but I suspect its similar. However, on occasion I find indole in my crude product due to protodeborylation, and the odour has not been pronounced enough to warrant concern.

[Edited on 5-5-2016 by DJF90]

aga - 5-5-2016 at 13:31

Have dogs, cats and children.

The experience makes it easily possible for a dog to puke then eat it's own vomit without bothering you at all during an evening meal.

Same with a puking infant : they just do that. They also crap their pants, piss everywhere and fart. Also happens with adults under some circumstances.

Smells ? If it's identifiably non-lethal, well, ignore it or move upwind.

So far i've not bought or made any Smell that is intolerable.

Dangerous smells are far more important to learn.

It's one thing to puke because you do not Like the smell.

Quite another thing to be literally puking your guts up through your empty eye sockets.

zed - 5-5-2016 at 13:45

At room temperature, it has a mild floral scent. That is, when you have a whole open jar full, right in front of yer face and yer thoughtfully whiffing it.... Used to be able to buy it, reagent grade, without problems.

Last time I checked, Indole had become kinda spendy. Leastwise fer a cheapskate like myself.

Go ahead and get some. If the odor seems offensive to you, there are probably half a dozen guys here that would be happy to take it off of your hands. At a reasonable price, of course.





Dr.Bob - 5-5-2016 at 18:14

Indole is not too bad, I worked with indole for almost 3 years of research. But 3-methylindole has the informal name of skatole, you can guess why. It is much worse. Fortunately, I did not make but one or two derivatives of it, thankfully less volatile ones.

a nitrogen rich explosive - 6-5-2016 at 06:51

Thioacetone made people in Freisburg puke from 200 metres. The town was evacuated.

Nicodem - 6-5-2016 at 09:33

Indole is a very pleasant smelling compound, though at higher concentration it can be a bit overwhelming and "chemical-like". The smell is extremely similar to naphthalene's. I would not be so sure of distinguishing the two. I guess most people are familiar with the smell as it is the smell of jasmine flowers. There is no fecal component to the smell - whoever told you that was bullshiting you (or maybe giving you bull feces). Nevertheless, try not inhaling to much indole as it is somewhat toxic.

Etaoin Shrdlu - 6-5-2016 at 10:14

Quote: Originally posted by Nicodem  
There is no fecal component to the smell - whoever told you that was bullshiting you

Indole absolutely has a fecal smell. It is used in perfumery specifically for this purpose (and of course for the jasmine impression). Without the benzyl acetate/linalool/methyl anthranilate to push things in a floral direction it smells decidedly more like decomposition than one would expect being used to jasmine. (It is a significant part of the aroma of feces, believe it or not - bad breath as well.) It is however not nearly as awful as skatole and retains something of a floral impression even at high concentrations.

Maybe you don't smell it but I left a bottle cracked open by accident and when I came back later there was definitely a barnyard/toilet aroma.

It won't wreck the house, doesn't linger unless you spill powder around or something.

Dr.Bob - 6-5-2016 at 10:16

I made mostly indole derivitives, but could easy distinguish them from naphyl compounds in my experience. There is a slight earthy smell to indoles in my opinion. But this thread reminded me of one of my first job interviews, where a senior chemist asked me a question that was something like, how would you identify this liquid, handing me a beaker full of a clear liquid. I simply said, it is ethyl acetate, merely by the smell, but then went on to describe about 10 methods to confirm that (BP, NMR, IR ester peak, MS, solubility, refractive index, density, reactivity, etc). The chemist laughed when I identified it within 3 seconds and offered me the job before I left. He also asked me how I could tell it apart from acetone, my first answer was smell, then I said water miscibility, and he was again pleased with such a simple answer.

mayko - 6-5-2016 at 12:36

Overwhelming is a good description for high concentrations of indole. It is recognizably a component of the smell of poo, and the smell is certainly reminiscent. But I'd hesitate to say that it smells 'fecal'; the sulfurous components of feces being a pretty essential component IMHO. I'm glad to hear it confirmed that it's a component of halitosis; I sometimes smell it upon my dental floss.

The single most striking thing about its smell to me is its intensity - I could smell the flowery mothball smell in my living room several hours after unwrapping, but not opening, the sealed bottle I'd received in the mail.

myristicinaldehyde - 6-5-2016 at 12:41

Quote: Originally posted by Nicodem  
Indole is a very pleasant smelling compound, though at higher concentration it can be a bit overwhelming and "chemical-like". The smell is extremely similar to naphthalene's. I would not be so sure of distinguishing the two. I guess most people are familiar with the smell as it is the smell of jasmine flowers. There is no fecal component to the smell - whoever told you that was bullshiting you (or maybe giving you bull feces). Nevertheless, try not inhaling to much indole as it is somewhat toxic.


Yes! It makes one think of feces, but it isnt feces-like. Some varieties of honeysuckle and Hoya smell like this.

Electra - 10-5-2016 at 13:13

I'm not sure why the wikipedia lists it as smelling fecal like. Having smelled it today, the smell is very flowery. I did however walk by some sewage recently and I can actually detect the indolic aroma after having smelled the pure compound.

I guess fecal does describe it, in some way, but I think that's a bad word to use to describe it, because people think poop when they hear the word fecal, not flowers.

ScienceHideout - 10-5-2016 at 13:58

I have no problem admitting that I like the smell of indole. Everyone I work with thinks it smells bad, but honestly it is very mild. It is very reminiscent of naphthalene but a bit 'warmer.'

I guess everyone's nose is different.

I've smelled a lot of different chemicals and there really aren't too many that I can't put up with. I hate the smell of ammonia and chlorine. Nothing else bothers me. I do OK with adamantanethiol, triethylamine, ethanolamine, pyridine, butyric acid. Nothing stinks to me in the organic world! :D

zed - 16-5-2016 at 17:50

Ummm. Maybe this is genetic. To some of us it smells flowery and inoffensive. Others describe it as "fecal". Dunno. Purity, could also be a factor.