alcohol + acetate = synergy?

[Zongo]

Did I understand this correctly and an alcohol and it's corresponding acetate synergize together in terms of their notes lasting longer? If I have Geraniol in my formula, is it reasonable then to add some Geranyl acetate, not only to make the odor more complex, but to make the Geraniol note disappear less quickly?

 

[parker25mv]

They do "synergize" well together. Perfumery is all about balance. Very oftentimes, in both nature and perfumery, the acetate version of something will be used along with the terpenic alcohol. Often you might find, for example, 60% linalool with 40% linalyl acetate (relative proportions).

They do often blend together well. (That is definitely not to say that they always have to be used together)

It will not make the note "last longer". (Linalyl acetate evaporates just a little bit faster than linalool, actually)
Linalool apparently has a much lower odor threshold than linalyl acetate, so it is not as if linalyl acetate is stronger in smell.

I really do not know, but if you are finding that the acetate allows the note to last longer, it might be because you can use more if it without it making the smell overpowering initially. (since the acetates are softer and not as sharp as the alcohol)

 

[Zongo]

Already assumed I had that incorrectly in memory. Thanks for clarification, Parker.

 

[perfumer86]

the acetate versions usually have a more complex odour profile, bit fruity etc. and yes they often complement each other. try this, geraniol and genaryl acetate, 1:2. linalool and linalyl acetate, 1:2. 2 hedione and 1 IES, your on your way in french fresh cologne style.

 

[Zongo]

As a staircase wit, I found the line that originally led me to the (false?) conclusion that
alcohols may extend the odor life of their acetate-counterparts:

Btw. Hydroxycitronellol is not as important as Hydroxycitronellal; it's used
originally to stabilize Hydroxycitronellal and to extend its odor life.

IIRC it was written by someone here on basenotes, but can't recall his name anymore.

 

[perfumer86]

As a staircase wit, I found the line that originally led me to the (false?) conclusion that
alcohols may extend the odor life of their acetate-counterparts:

IIRC it was written by someone here on basenotes, but can't recall his name anymore.

most alcohols tend to be more longer lasting than their acetates.

 

[parker25mv]

"Hydroxycitronellol is not as important as Hydroxycitronellal; it's used
originally to stabilize Hydroxycitronellal and to extend its odor life."

Keep in mind that "extend" can have different meanings. It does not necessarily mean it will make the smell persist longer.

One meaning is that it could be used to extend the amplitude of the smell.
(There could be various reasons why it might not be desirable to use more of the original AC)

 

[David Ruskin]

most alcohols tend to be more longer lasting than their acetates.

Not true. Geranyl acetate is longer lasting than Geraniol. Phenyl ethyl acetate is longer lasting than PEA. And so on.

 

[Casper_grassy]

As a staircase wit, I found the line that originally led me to the (false?) conclusion that
alcohols may extend the odor life of their acetate-counterparts:

IIRC it was written by someone here on basenotes, but can't recall his name anymore.

Hydroxycitronellal is an aldehyde.

 

[xii]

Not true. Geranyl acetate is longer lasting than Geraniol. Phenyl ethyl acetate is longer lasting than PEA. And so on.

That doesn’t sit right with me. I literally never study materials in isolation so I needed to test it. The opposite seems much more to my nose. And anyone’s around to ask.

Ethanol vs ethyl acetate would be much more convincing for me, but it still doesn’t disprove the original statement, that alcohols are more tenacious than their acetates. For this we would need to argue the opposite, that is that most acetic esters last longer than their respective alcohols.

 

[David Ruskin]

Retention time of geraniol is less than the retention time of geranyl acetate; retention time of PEA is less than the retention time of phenyl ethyl acetate. Etc., etc.

 

[xii]

Retention time isn’t really the same as tenacity. The former means how quick stuff travels through a long tube, the latter is way more complex: it involves for instance detection threshold and how freely the substance parts itself from a blotter. Two somewhat related, but quite different things.

 

[perfumer86]

Retention time isn’t really the same as tenacity. The former means how quick stuff travels through a long tube, the latter is way more complex: for instance detection threshold and how freely the substance parts itself from a blotter. Two somewhat related, but quite different things.

true. odour life is not the same as odour impact. i agree

 

[David Ruskin]

Boiling point of geraniol 230 deg C
Boiling point of geranyl acetate 245 deg C
Boiling point of PEA 225 deg C
Boiling point of phenyl ethyl acetate 232.6 deg C


For the last time, in my experience, acetates last longer on a smelling strip than does the equivalent acetate. If you find otherwise then bully for you.

 

[Casper_grassy]

In regards to commonly used Alcohols and Acetates, IME those acetates last longer.

Some alcohols are more diffusive though than their acetate counterparts in blends such as Linalool and PEA.

 

[xii]

So I‘ve concluded another test, this time neat, before it was at 10%, and two days later geraniol and phenylethyl alcohol are still there the respective acetates are long gone. I mean so long gone that no amount of convincing and physical properties data will bring them back to the blotters.

Not that it‘s terribly important to me. I’m kind of aware that acetates tend to be more volatile that their MW would suggest, and for a good reason, but that’s all I bother to remember.

 

[parker25mv]

Not true. Geranyl acetate is longer lasting than Geraniol.

I don't really know, but the vapor pressure data seems to suggest otherwise.
geraniol - 0.008507 mm Hg @ 23° C
geranyl acetate - 0.014914 mm Hg @ 23° C
data comes from International Flavors & Fragrances

(higher vapor pressure typically means it will evaporate faster)
(and I don't think this is just some error or misprint in the data; the data shows a similar situation for linalool and linalyl acetate)

an explanation: Yes geranyl acetate is a bit bigger of a molecule, but it also lacks an OH bond, so there is no hydrogen-bonding, such as there is with water for example

It might interest you to know that you are correct about phenylethyl acetate lasting longer, however.
phenylethyl alcohol - 0.0868 mm Hg @ 25 °C
phenylethyl acetate - 0.056000 mm Hg @ 25.00 °C

I have no idea why the difference, but speculate it might be because the ratio difference in molecular weight turns out to be just a bit bigger when it comes to those phenylethyl compounds (PEA C-8 versus geraniol C-10, so 8:10 versus 10:12) so this seems to be close to a "break-even" point. (another reason might have to do with geometry, PEA molecules may not fit together so well in a way that optimizes both the connection of their OH groups and the contact with the rest of the molecule on the same plane)

 

[parker25mv]

So I‘ve concluded another test, this time neat, before it was at 10%, and two days later geraniol and phenylethyl alcohol are still there the respective acetates are long gone. I mean so long gone that no amount of convincing and physical properties data will bring them back to the blotters.

This could just be because the acetates are several times weaker in smell strength than the alcohols.

While that could be considered "tenacious", it does not really mean they are "longer lasting".

In other words the human nose can detect the alcohol at lower odor thresholds.

I think you would have to adjust your test if you were going to try to determine if one really lasts longer than another.
For example, start at extremely low concentration levels and calibrate to see how much more (how many times more) geranyl acetate is required to be at a perceptible level than geraniol. Then, with that ratio determined, run the evaporation strip test again using those ratios.

 

[David Ruskin]

I am becoming bored with this. My own experience makes me conclude that PEA is more volatile than phenyl ethyl alcohol; geranyl acetate lasts longer than geraniol. I have compared on smelling strips and know this to be true. If you are finding different results, tant pis. I cannot vouch for your results, nor the quality of your smelling strips, nor indeed the quality of your ingredients. You do what you want, and I will know what I know. You seem determined to prove me wrong; go fill your boots.