Why is aspirin not a sweet smelling substance?

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ANEXIS kZstaR
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Despite it having a benzene ring in its structure?
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username878045
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Because aromatic rings don't automatically lead to sweet smells...
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ANEXIS kZstaR
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(Original post by PythianLegume)
Because aromatic rings don't automatically lead to sweet smells...
Could you elaborate on that please, since aroma is Latin meaning fragrance, then how come organic materials produced from plant material gives off fragrant smells whereas in benzene it is odourless.
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username878045
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(Original post by ANEXIS kZstaR)
Could you elaborate on that please, since aroma is Latin meaning fragrance, then how come organic materials produced from plant material gives off fragrant smells whereas in benzene it is odourless.
Umm, the Chemistry of smell is ridiculously complex. As simple things as different stereoisomerism can completely alter the smell. No-one really knows how to predict smells. The name 'aromatic' is historical, and exists purely by coincidence. It is unrelated to the smell of compounds.
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F1's Finest
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(Original post by PythianLegume)
Because aromatic rings don't automatically lead to sweet smells...
This.


Also touching on the matter of smells in Chemistry, as you said above is a very complex matter! It's a combination of stereoisomers, more than one benzene ring perhaps and maybe positional isomers that can lead to such a variety of compounds (which might be the reason for it having a scent!??)

Something like the famous 2,4,6-trichlorophenol compound is TCP and is used as an antiseptic that has a pleasant odour.
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ANEXIS kZstaR
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(Original post by PythianLegume)
Umm, the Chemistry of smell is ridiculously complex. As simple things as different stereoisomerism can completely alter the smell. No-one really knows how to predict smells. The name 'aromatic' is historical, and exists purely by coincidence. It is unrelated to the smell of compounds.
So benzene is an aromatic compound, with aroma meaning fragrance, but benzene isn't actually sweet-smelling and it is all a big co-incidence then?
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ANEXIS kZstaR
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(Original post by James A)
This.


Also touching on the matter of smells in Chemistry, as you said above is a very complex matter! It's a combination of stereoisomers, more than one benzene ring perhaps and maybe positional isomers that can lead to such a variety of compounds (which might be the reason for it having a scent!??)

Something like the famous 2,4,6-trichlorophenol compound is TCP and is used as an antiseptic that has a pleasant odour.
I believe that aspirin is C9H8O4, therefore there can only be one benzene ring at most in that structure, so hust a co-incidence then since stereoisomers is the reasoning and not aroma=fragrance or anything like that.
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labking
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(Original post by ANEXIS kZstaR)
So benzene is an aromatic compound, with aroma meaning fragrance, but benzene isn't actually sweet-smelling and it is all a big co-incidence then?
Benzene does smell aromatic... Though I wouldn't recommend smelling it due to its carcinogenic properties.
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ANEXIS kZstaR
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(Original post by labking)
Benzene does smell aromatic... Though I wouldn't recommend smelling it due to its carcinogenic properties.
I maeant aspirin isn'ts sweet smelling..
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labking
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Volatility also comes into play with compounds and if they smell or not.. benzene is highly volatile but asprin is not... smells are very specific.. small changes in chemical structure have large impact on smells (compare carboxylic acids and esters)
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labking
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(Original post by ANEXIS kZstaR)
I maeant aspirin isn'ts sweet smelling..
There is more to the structure of asprin than the benzene ring.... toluene (benzene with methyl group) smells completely different to anisoles (benzenes with methoxygroup)
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ANEXIS kZstaR
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(Original post by labking)
There is more to the structure of asprin than the benzene ring.... toluene (benzene with methyl group) smells completely different to anisoles (benzenes with methoxygroup)
But aspirin being an aromatic compound and it containing a benzene ring - has nothing to do with it having no odour.

So just coincidence that aspirin has no "aroma" despite it being an aromatic compound, then?
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Hype en Ecosse
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(Original post by ANEXIS kZstaR)
But aspirin being an aromatic compound and it containing a benzene ring - has nothing to do with it having no odour.

So just coincidence that aspirin has no "aroma" despite it being an aromatic compound, then?
Aspirin is aromatic
Aspirin does not have a sweet smell
Therefore, not all aromatic compounds have an aroma. The presence of a benzene ring doesn't automatically cause a fragrance. The naming is coincidental.
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ANEXIS kZstaR
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(Original post by Hype en Ecosse)
Aspirin is aromatic
Aspirin does not have a sweet smell
Therefore, not all aromatic compounds have an aroma. The presence of a benzene ring doesn't automatically cause a fragrance. The naming is coincidental.
Exactly what I wanted to know.

Thank you.
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Borek
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To quote wikipedia on http://en.wikipedia.org/wiki/Aromatic_hydrocarbon:

An aromatic hydrocarbon or arene (or sometimes aryl hydrocarbon) is a hydrocarbon with alternating double and single bonds between carbon atoms forming rings. The term 'aromatic' was assigned before the physical mechanism determining aromaticity was discovered; the term was coined as such simply because many of the compounds have a sweet or pleasant odor.
So, in chemistry 'aromatic' means something different.
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