Originally Posted by Hammilton
When you use the word aromatic are you using it in the chemistry sense? If so, I have to disagree. No one wants to smell like aromatic hydrocarbons... Well, outside of gasoline huffers.
And frankly the chemicals responsible for musk scents are rather small molecules.
I don't think the issue is size or stability but rather volatility.
My interest lies in structural activity relationships.
I hadn't noticed this when it was posted back in July, but just in case anyone was confused by it:
Oddly enough, this being a perfume forum and everything, I was using the term aromatic
in the sense it is used in perfumery - which also happens to be my area of expertise.
As it happens the chemistry sense of the word also applies to the majority of natural perfumery materials and the aroma chemicals that they are composed of as well as to most of the synthetic aroma chemicals that are used in the industry. Most of them are mono or poly-cyclic compounds composed of hydrogen and carbon, often with oxygen or nitrogen in substitution. What was it that you
thought aromatic meant in chemistry?
So lot's of people do indeed want to smell like aromatic hydrocarbons
and indeed many of the synthetic materials use in perfumery are derived from the same petrochemical base that gasoline (petrol to those of us on this side of the Atlantic) is derived from . . .Size matters
: to describe something as large or small requires a context as these are relative terms. The context in this case being perfume and perfumery, you need to know that there is a practical upper limit to the size of molecule that the human nose can detect.
That being a molecular weight (mw) of 296 (the mw of labdane, the largest known odourant). This context is slightly complicated by the fact that at the upper end of the weight limit anosmia (inability to smell a particular odourant) increases - so the bigger the molecule the more people are anosmic to it. In the case of Galaxolide for example - mw 244.38 - it is thought that roughly half the population are anosmic to it. Hence in the context of perfume synthetic musks are large - amongst the largest molecules that you can smell at all in fact.
There is a good article on Wikipedia concerning the structure of synthetic musks
(although it erroneously describes only three major structural classes, it does go on to describe the four most important, only missing non-nitro aromatic musks).
There is also a good exploration of the science involved, and the limitations of the use of quantitative structural activity relationships to odour perception, in this article by Luca Turin
. Though I should say that most experts in the field do not agree with Luca's conclusions, his overview of the science, up to about page 7, is uncontroversial.
I don't mind having my statements contradicted - that's how I increase my learning - but I do prefer it if you check your facts first.