Can I use just one aroma chemical to represent a specific note in an accord?

Who's going to stop you? You can do whatever you want.

Some molecules smell rich and complex, a lot smell one-dimensional and linear. Depends what you're going for...

(I'm sure some of the more experienced people here will give a more helpful answer!)

Most essential oils consists of hundreds of different aroma chemicals. Combined they make up the complete scent of, let's say a typical red rose. For instance, but not limited to citronellol, geraniol, nerol, linalool, phenyl ethyl alcohol, farnesol, stearoptene, α-pinene, β-pinene, α-terpinene, limonene, p-cymene, camphene, β-caryophyllene, neral, citronellyl acetate, geranyl acetate, neryl acetate, eugenol, methyl eugenol, rose oxide, α-damascenone, β-damascenone, benzaldehyde, benzyl alcohol, rhodinyl acetate and phenyl ethyl formate. (Thanx Wiki!).

All these aroma chemicals represent a part of the Rose scent and can combined in other ratios produce something completely different! As a matter in fact, a lot of flowers will have citronella, nerol, linalool et cetera in them! And eugenol on it's own resembles nearly 100% of what people think of as cloves, for example.

Picking solely "rose oxide" from the list, it will give you a scent described as "rose green floral geranium powdery metallic", you strengthen the metallic part by adding linalool and the sweet part by benzaldehyde, for instance. Layer by layer, the full rose comes to bloom

So, yes, you can pick one aroma chem, which faintly reminds on a part of a flower, but always need *a lot* of different aroma chems to create a true scent resembling the original and which has some multidimensional interesting parts while developing on skin or a blotter.

To complicate things even more, aroma chemicals can play part(s) in top, middle and/or base notes or as blenders with other compounds.

We are talking delicate balances here. That's why i consider perfume formulations as part science and part art

And to answer your Lily-of-the-Valey question in-depth See this:

Attachment 19582

Happy perfuming!

Using a single aromachemical for a note may succeed, but more often than not will succeed in making it smell thin.

Lots of good advice here already but I just want to comment on pre-made accords: if you can get accords where the formula is either published or supplied with the product then that's fine. But, aside from some industry standard products, I wouldn't recommend working with pre-made accords that are proprietary to a particular supplier because two things follow from doing this:
1) you are stuck with that supplier - and their prices - forever. If one day you want to make litres of the fragrance you've designed with such an accord you can never benefit from the price reductions that come with scale and if that supplier reformulates, goes out of business or just discontinues the accord you're stuffed.
2) because you've no idea what's in it you will only have learned to work with that completed accord, not the components. So when you are ready to work with more materials you'll have to start the learning all over again.

Just taking Lily of the Valley as an example, if the accord taken from Curtis & Williams seems too daunting, just buy some Hydroxycitronellal and use that. It's a pretty good facsimile of the flower scent and later, when you are ready, you can start working with more materials to complement it but meanwhile you'll know all about how hydroxycitronellal behaves with your other ingredients: that learning won't be wasted.

With rose it's more difficult because it's such a complex scent, but in that case there are industry standard products that you can use such as Rose Givco or Dorinia SA E (by Givaudan and Firmenich respectively).

One or other of these solutions should serve for most of the notes you want to work with.

Thanx Chris, for finding the source of the picture! Found it on the internet and did not know the origin. Seems a great book! Could you recommend buying it for an amateur like me?
Best!

It's an excellent book, designed to give a general introduction to perfumery and the perfume industry for those starting out (it's used as a textbook at the University of Portsmouth where Tony Curtis teaches).

I still find things of value to look up in it now and I found it to be the most useful introductory work available, so I'd say it's well suited for someone like you with some experience of blending already: only a few areas of it are likely to be too basic, though you may find the chapters on structures of perfumery companies and the like less interesting.

excellent answers so far. there is another facet that's not touched upon. it can sometimes be better to just use one chemical, or just a few. for the larger structure, the single-mindedness of single molecules can be beneficial, they form a strong bone structure without muddiness. however, they will need modifiers and detailing, filling and fleshing out, and so on. so when we zoom in to the smaller scale, where you (for example) need a slight vanilla nuance, on the threshold of detection, it's often better for precision and clarity's sake to use just some vanillin (or whatever fits best) rather than build a complex accord (say, the absolute or a tincture combined with this and that.) complexity is great when it evokes richness and depth, softness, it generally makes more interesting 'characters' ; but pile up too much and you will end up with a pool of obscure brown mud.

you got it.

but also note the other point, larger scale work, only slightly less on topic. caron pour un homme is a good example. it's dominated by basically two ingredients: lavender oil and vanillin. admittedly there is more to that vanilla than just vanillin, for instance coumarin is an important element here, it looks easier than it is. but this vanilla accord is kept lean on purpose; it's based on a single molecule.

most single molecules are thin or sharp by themselves, they have often simple, sometimes singular scents that the mind gets tired of all too soon, perhaps a bit like a drunk person saying the same thing over and over again. but don't be fooled. use them for razor-like cuts when you are sculpting a perfume shape. sometimes disadvantages can prove extremely useful.

i'm not sure at all what you mean. who gives these rates?

sometimes it's easier to work with pre-diluted stuff, i would not like to deal with pure civet for instance. so it might be stated in a formula as 5 parts civet abs 10%. which would also be true if you used a tincture, but i am not sure if and how the strength of the tincture was noted in the formula. it think something like, 5 parts civet tincture 10% in case the tincture was made with 9 parts alcohol and 1 part civet paste (the 5 parts bit is just for example and not important.)

is this what you mean?

When a Raw Material is first introduced to Perfumers the standard way of showing it is in a demonstration formulation. A sample of the formula is shown with the new material, and one without so as to show the effect the new material has. It is also usual to recommend an average amount (e.g. up to 1.0%) so as to give the perfumers some sort of idea as to how to use it. It is a recommendation only, and not set in stone. Ultrazur, for example, is a very strong and difficult material to use; so the recommended dosage is quite small. Same with Civet. There is nothing to stop you using anything at any amount you want, to achieve the result you want.