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saizine
12-17-2012, 10:27 PM
I'm looking for a chemical or chemical compound that, when heated, gives off a distinct odor--not necessarily a distasteful one (i.e. ammonia or sulfur), but definitely a noticeable one. I'd actually prefer it if the smell wasn't one that would make others recoil! The character who is handling this substance is one who is familiar with chemistry, studied to postgraduate degree level and maintains an under the radar, at-home laboratory (UK, present era).

I've done a little bit of research and looked through my old chemistry notebooks (I'm afraid I only ever got through high school chemistry, and not confidently, I might add) but I can't recall anything that doesn't have a distinctly unpleasant odor--nothing's coming to mind that just has a noticeable smell.

Thoughts? Thanks in advance.

Chris P
12-17-2012, 10:47 PM
Does the smell have to be related to what he's doing in the lab? If so, you'll have to go into more detail about what he's doing.

There are lots of things that have distinct smells, including plant essential oils, which give things like spearmint, orange peels, lemon grass, etc. their distinct flavors. I work with pesticides, and I can identify many of them based on their odors, especially the organophosphates. Each of the common solvents (acetone, ether, ethyl acetate, hexane, benzene) have unique odors too, and not everyone thinks they are unpleasant.

Mutive
12-17-2012, 11:43 PM
All smells are chemical, and most odoriferous compounds will become more so when heated.

Is there anything you'd be looking for in particular? Like Chris noted above, an awful lot of both common chemicals and biological compounds have smells...

waylander
12-18-2012, 01:07 AM
alpha-pinene

saizine
12-18-2012, 01:14 AM
I had a feeling we'd run into the 'all smells are chemical' point! I completely understand, I don't like it when products claim to be 'chemical-free' either, but I was getting a bit stuck for a descriptor! I suppose I should say that the odor would ideally be something that wouldn't normally be in a house and has a scent that would perhaps alarm someone who was there--you know, the sorts of smells that might make you want to check that there aren't any broken pipes around? Not necessarily unpleasant, just odd enough to notice.

The smell isn't directly related to what he's doing. I hadn't really thought of essential oils, though they weren't really what I was looking for. Not really the character's style, if you know what I mean.

Pesticides are an interesting option--I'd love to hear a little bit more about those specifically.

In the labs that I did as a student, there were several of them that relied on smell to know whether or not you were proceeding correctly. For example, if you were smacked around the head with the strong smell of rotting eggs, you were on the right track. Reactions that produce odorous gases when heated would also be an interesting line of inquiry.

Thanks Chris P and Mutive for replying!

ETA: Sorry waylander, I think I posted while you were posting! Alpha-pinene sounds interesting (I've just had a quick read of the Wikipedia page), although I do wonder what the smell would be? Is it very pine, or rosemary? Or is it not particularly either? I am liking the link with plant emissions with temperature/light. I could work with that. :)

Xelebes
12-18-2012, 01:16 AM
Solutions with trace amounts of cyanide. It will smell like almonds. Alternatively, you could be crushing almonds or working with shocking-pink-dragon millipedes and give off that cyanide smell.

MagicWriter
12-18-2012, 02:52 AM
Eucalyptus?

Maybe look into something that candle companies use? Or aromatherapy stuff? Heated massage oils?

Good luck!

waylander
12-18-2012, 03:03 AM
Alpha pinene is intensely 'piney', not surprising really as it is obtained from pine resin.

Triethylamine perhaps? Smells rather fishy

WeaselFire
12-18-2012, 06:14 AM
I'm looking for a chemical or chemical compound that, when heated, gives off a distinct odor--not necessarily a distasteful one (i.e. ammonia or sulfur), but definitely a noticeable one.
Esters. Plenty to choose from, depending on what you want. Food, cosmetics/perfumes, even plastics would be common products.

Of course, it depends on why you need the chemical. Must it explode? Cause injury or death? Defeat an alien with eighteen legs and forty-six eyes? Or just be stinky?

Jeff

BenPanced
12-18-2012, 06:27 AM
alpha-pinene
Phentermine?

calieber
12-18-2012, 09:40 AM
I had a feeling we'd run into the 'all smells are chemical' point! I completely understand, I don't like it when products claim to be 'chemical-free' either, but I was getting a bit stuck for a descriptor! I suppose I should say that the odor would ideally be something that wouldn't normally be in a house and has a scent that would perhaps alarm someone who was there--you know, the sorts of smells that might make you want to check that there aren't any broken pipes around? Not necessarily unpleasant, just odd enough to notice.

Gas companies add mercaptan to the odorless gas so it's not odorless.

I don't always notice it, but my girlfriend does and gets up my ass about it most people do, and it is definitely alarming.

Pyekett
12-18-2012, 04:02 PM
To echo WeaselFire, there are fruit esters that are often made as organic chemistry lab experiments.

Here's a powerpoint on making Isopentyl (Amyl) Acetate Ester (http://tinyurl.com/d6gmd9k), aka "Banana Oil." It smells like banana bubble gum, if I recall correctly. The smell is intense enough--though not unpleasant if you like bananas--that if I ran across it in an apartment or house, I'd start looking for overripe fruit.

Your MC could, hmm, be making it to test the calibration of his measuring equipment? Nostalgia for organic chem 101? Likes the smell of bananas and decided to dick around, geekstyle?

Added: Powerpoint is hosted at George Mason University, looks to be class instructions on how to synthesize compound and do write-up, and has no viruses I can see. It even shows the physical setup. That could be helpful.

mirandashell
12-18-2012, 04:11 PM
Gas companies add mercaptan to the odorless gas so it's not odorless.

I don't always notice it, but my girlfriend does and gets up my ass about it most people do, and it is definitely alarming.

You really don't smell that? Wow. That's one of the smelliest substances on Earth and is added to natural gas for that reason. It's very distinctive.

You are the only person I've ever heard of that can't smell that.

calieber
12-18-2012, 08:12 PM
It's likely that it doesn't register. She's more sensitive to odor than I am anyway.

I don't know if mercaptan qualifies as the questio was stated; I don't know what happens if you heat it.

WeaselFire
12-19-2012, 05:27 AM
You are the only person I've ever heard of that can't smell that.
Then I'm the second. Except I have an excuse, sinus cancer destroyed my sense of smell.

At least the laundry's always clean! :)

Jeff

espresso5
12-19-2012, 06:45 AM
Synthesizing methyl salicylate (oil of wintergreen) is a classic organic chemistry experiment. It's definitely a distinctive, somewhat pleasant, odor.

blacbird
12-19-2012, 07:59 AM
I'm looking for a chemical or chemical compound that, when heated, gives off a distinct odor--not necessarily a distasteful one (i.e. ammonia or sulfur), but definitely a noticeable one. I'd actually prefer it if the smell wasn't one that would make others recoil! The character who is handling this substance is one who is familiar with chemistry, studied to postgraduate degree level and maintains an under the radar, at-home laboratory (UK, present era). .

As a grad student I worked in a chemical laboratory in which the solvent xylene was in common use. It has a distinctive, not unpleasant, almost perfumey sweet aroma. It's a common solvent for many operations (and is also carcinogenic)

caw

shaldna
12-19-2012, 04:11 PM
I worked in a lab for a couple of years and some of the smells were intense - one of the tests we used to do involved adding chloroform to sulphuric acid and heating it - that smell was strange, very sharp, very chemical but not necessarily that foul. Took some getting used to.

That was the same job where I learned why you don't pour chloroform down a sink and then rinse it away with hot water. :(

ClareGreen
12-19-2012, 05:53 PM
Oops, Shaldna. :)

Another one would be acetone - it smells like pear drops, but is best not used in an enclosed space.

Chris P
12-19-2012, 06:10 PM
Pesticides are an interesting option--I'd love to hear a little bit more about those specifically. :)

Most recent pesticides are developed to not have offensive odors, but there is a characteristic "chemical" smell to nearly all of them. They don't really smell like anything else but they do have their own smells. Now, whether it's the active ingredient or some of the carriers, that's another question. The older chemicals (DDT, chlordane, aldrin, etc) were oil soluble and the petroleum carrier usually overpowered the odor of the chemical.

Chlorpyrifos always reminded me of black pepper. All of the organophosphates smell pretty vile. They used to spray malathion from trucks in my hometown to kill mosquitoes, and it was very, very bitter. As someone else mentioned, the older cyanide pesticides smelled like almonds. The newer products like fipronil and chlorfenapyr smell like Elmer's glue. I cant' recall which product it was, but I would get a garlic taste in my mouth working with one pesticide. Wasp sprays like Raid (which contain pyrethroids) are so loaded with fragrance that I choke on them; I'd rather smell the pesticide! NPK fertilizers are what you're smelling in the garden shops.

saizine
12-19-2012, 10:32 PM
Of course, it depends on why you need the chemical. Must it explode? Cause injury or death? Defeat an alien with eighteen legs and forty-six eyes? Or just be stinky?

I'm really looking for one that is ultimately benign (i.e. short term exposure is unlikely to hurt you in the long-term) but is noticeable enough for a visitor to notice and question.

All your suggestions have given me a lot to think about! Thanks very much. :)

Anaximander
12-20-2012, 01:24 PM
There's a class of chemicals known as "aromatic" which include benzene compounds; it's a common high-school experiment to make some in the lab. The one I remember making is methyl salicylate, a benzene-based ester which smells like Deep Heat, a fragrance known as "oil of wintergreen". There's also limonene, which is responsible for the smell of citrus fruits; it can be easily extracted from their skins (another high-school chem lab experiment). Limonene is probably not as good for your purposes; it could more easily be mistaken for actual citrus, or assumed to be a common cleaning product. Methyl salicylate is a more unusual smell while some plants do give it off, they're not as common and it's not the kind of smell you tend to have around. I'd definitely notice it and wonder; my first thought would be of Deep Heat cream and not the chemical, but I'd be curious. It's also not that dangerous - it is toxic, but only if ingested or after long exposure. It's safe enough for teenagers to make in a lab, anyways.

Marta
01-11-2013, 06:30 AM
To echo WeaselFire, there are fruit esters that are often made as organic chemistry lab experiments.

Here's a powerpoint on making Isopentyl (Amyl) Acetate Ester (http://tinyurl.com/d6gmd9k), aka "Banana Oil." It smells like banana bubble gum, if I recall correctly. The smell is intense enough--though not unpleasant if you like bananas--that if I ran across it in an apartment or house, I'd start looking for overripe fruit.

I'll chime in agreeing with Weaselfire and Pyekett: Lots of esters to choose from; at least the simpler ones are known for their pleasant, fruity odors, and they're good raw materials for making any number of other compounds. So there'd be a good reason to have them in the lab, even if making them isn't the goal of the lab. But they'd tend to smell even if they're not heated, though heating (to a point) would make the smell stronger.