Aromachemicals for dummies

i found a large section of 'the secret of scent' a useful read, the part that gives an panoramic overview of the smell landscape. there are some blogs around that discuss aroma materials, just look around on the net and if you can't find the answers you need, ask.

i did find this document very useful. i got it from the txt files section of the perfumemaking group, and it was written by mike storer, who is perfumer and a basenotes member. many thanks, mike.

A tiny chemistry lesson

99.9% of the chemicals we used are composed of just three elements: carbon, hydrogen and oxygen. How they are linked to each other determines whether they are alcohols, aldehydes, acids, esters or ketones. There are also some nitriles (containing nitrogen) and the only "nitro" compounds are the old "nitro musks" which aren't used so much now. A few smell chems also have sulfur, but these are usually "meaty" or "nutty" and are used only in flavoring.

Alcohol... The name of the chem or brand name ends in -ol.
Aldehyde... The name ends in -hyde or -al.
Acid... The name ends in "-ic acid." (Säure in German)
Nitrile... The name ends in -ile
Ketone... The name of chem or brand name ends in -one.
A very few things end in -ene.. These chems contain no oxygen, just carbon and hydrogen. The chems for us are usually terpenes.

Alcohols oxidize with difficulty to aldehydes which oxidize easily to acids. In other words, in heat and light, alcohols will *slowly* begin to turn to:

Aldeydes which often smell more pungent than the parent alcohol. Aldehydes are the least stable of all categories and oxidize *easily* to acids.

We don't use many acids as they tend to be odorless or sour.

We use a lot of Esters. They are an alcohol bonded to an acid. You can tell it's an ester because the chem names look like this: first part ends in -yl (that's the alcohol) and the second part of the name ends in -ate (that's the acid)... Example: methyl phenylacetate. It can be called "the ethyl ester of phenylacetic acid" Another, the simplest chemically: methyl formate or methyl ester of formic acid.

Because our aldehydes are so unstable (they often come with a preservative antioxident), chemists have made some of them as nitriles instead of aldehydes. They tend to be more stable, are usually much stronger and sometimes have a harsher metallic tinge.

Ketones are the most stable of all. They don't oxidize under normal conditions. Examples: Isojasmone. Velvione, muscone. Hedione is misnamed because it is an ester, not a ketone, but it has a ketone element in it as it is methyl dihydronjasmONEate.

In other words, chems can be both esters and ketones at the same time, or alcohols and ketones, etc. These endings are chemical "groups" and some complicated chems can have a whole bunch of different groups hanging on them.

the secret of scent is very useful for a newbie, do make notes when you read it. and look things up over at www.thegoodscentscompany.com, they have every chemical i have heard of listed in a huge database. best way to search their site is via google 'site:www.thegoodscentscompany.com citral' if you're looking for a particular material like citral, or their odor index if you want to find out 'what smells like ...'. they list everything you need to know: descriptors, substantivity, strength, suppliers (complete with their descriptors), solubility, safety, physical properties, storage, et cetera.

i forgot to mention http://users.tpg.com.au/adsleh6r/TGSCsearch.htm a custom google search engine for tgsc.

and i second irina's suggestion.

one of these blogs is octavian's. if you read today's post on tulips, you will see what i mean. he is doing it for years, and his blog is becoming a great archive to search in with google (via the site:1000fragrances.blogspot.com/ method, see previous post).

i am thinking we should create a sticky on this subject, since this question is a good one and i see it being asked over and over again.
if the moderator agrees i can start a new thread were we can mention all the sources we can think of.

Reading is good, and all of the references given above are very useful. I think that you'll appreciate TGSC more when you actually start working with aroma chemicals and have some experience. It's pretty dry "reading" for starters!

Reading aside, there's no substitute for hands-on experience. My suggestion would be to start with some EOs and premixed accords from Perfumer's Apprentice (or some source in Canada) so that you already have a feel for what the odors are like. Once you're confident using those to make perfumes, you can move on to the pure aroma chemicals and start mixing your own accords. Sort of like learning to put together all kinds of structures with Legos before you learn to do the plastic manufacturing technique to make each individual piece from scratch.

One of the most comprehensive books on this subject for non-industry people... (I've got a copy myself)

http://www.amazon.com/Introduction-P.../dp/096087528X

"Introduction to Perfumery" is as thick and dense as a third-year College textbook. If you can get it for CA$70, that's cheap. I've paid more for new textbooks at College...

Then drop the lovely ladies at perfumersapprentice an online visit and order their aromachemical sampler package. I still have my original kit relatively unused, just in case I need to smell them again, eg to be reminded what Lyral smells like...

If you really want to learn more go to
http://groups.yahoo.com/group/perfumemaking/
and join in the discussions. The folks on this list are always willing to help out with any question, regardless of experience level.
Just, please, try a little research and hands-on experimenting yourself before asking general questions such as "how do I make a perfume for my girfriend"

where did you learn about the candle making? are there any good online sources?

I just now noticed (June of '10) that Gido reprinted the posting I made on our yahoo group "perfumemaking" (which is indeed wonderful). I'm grateful that my words are of some use to you here as well.
I noticed a couple of typos and remarks I should amend for the record.

I misspelled the proper chemical name for Hedione, so beloved since its use in Eau Sauvage brought its magic to the attention of all perfumers around the globe.
It's spelled methyl dihydrojasmonate. I stuck a stray "n" in there.

I neglected to mention two other important classes of perfumery molecules; the ethers, which are at least as stable as ketones –and lactones, which are a special subgroup of esters, actually. The difference is that lactones are made from molecules which are, shall we say, hermaphrodites? They form an ester with themselves, having one part of their molecule be an alcohol and another part of themselves an acid. They, well, they sorta "copulate" with themselves and form a circular structure of some type. Some very important musks are lactones, such as pentadecalactone. Some provide useful coconutty and peachy notes. Another oddball is ethylene brassylate, a very useful musk consisting of a double-ended long chain acid plugged in at both ends to a double ended alcohol.. technically an ester or lactone however you choose to view it. Again it's a sort of circle well-you-know-what.

A lot of the chems used in fragrancing aren't simply one class or another. Many, many valuable molecules consist of any combination of the listed classes, depending upon where you look on the molecule.
I just read back and see that I did mention that fact, but it's still worth repeating.

One more thing: Sulfur-containing molecules are more useful in perfumery than my posting suggests. Their use is increasing as perfumers learn to work with these mostly hyper-potent chems. They often provide exotic fruity notes, like mango, passionfruit, etc, which have come more into vogue, thanks both to consumers' taste and also their slow introduction to perfumers. The same goes for some sulfurous nutty / coffee / chocolate notes which lie at the basis of the foody/gourmand trend.

I will be posting a very interesting article, I think, about "watery/fresh air/ozonic" type notes and a bit of history about why we perceive them as we do.
I'll have it up on http://michaelstorer.com under Perfumer's Page in a few days after it's published by Qondio which gets first dibs with it.

Hiya
As GourmandHomme says the most comprehensive and reasonable book is Introduction to Perfumery by Tony Curtis and David Williams.
http://www.amazon.co.uk/Introduction...0614293&sr=8-2
£40 in UK.
There are a few chemicals that you find again and again in so many perfumes: linalool, coumarin, limonene etc.... I often keep the ingredient lists from perfumes I own for the aromachemical refrences.
G