Sciencemadness Discussion Board

[Video] Making tert-amyl acetate. grape aroma

MichaelBijanAfghani - 23-11-2021 at 21:02

Video: https://youtu.be/3wA__rOdcF8



I have lots of experience with Fischer esterification, but tertiary alcohol esters have not been explored much. The Internet and literature seem to be devoid of odor info for any tertiary alcohol ester greater than tert-butyl acetate (said to have a blueberry or camphor kind of smell). So I've always been curious about tert-amyl acetate.

Tert-amyl alcohol and diethyl ether were dried over molecular sieves overnight. The reaction flask was flame dried. Tert-amyl alcohol (18.4 mL / 0.172 mol), N,N-dimethylaniline (26.5 mL / 0.209 mol) and 25 mL diethyl ether were added to the flask. The flask was fitted with a graham reflux condenser with circulating ice-cold water, and an addition funnel. The mixture was heated to reflux. Acetyl chloride was added to the addition funnel. I meant to add (14.1 mL / 0.198 mol) but made a mistake with the addition funnel and lost some down the sides, so I added an unknown excess (around 20 mL I estimate) which is okay because it will be neutralized in workup. All the acetyl chloride was added over 1 minute, and addition caused bubbling of white HCl mist. The mixture was refluxed for 1 hour.



N,N-dimethylaniline hydrochloride white precipitate

After cooling to RT, there was white N,N-dimethylaniline hydrochloride precipitate at the bottom of the flask. 25 mL of water was added to dissolve it. The ether layer was extracted twice w/ ice cold 10% H2SO4 until the drained aqeuous layer no longer formed white precipitate on addition of NaOH solution. then washed twice w/ sat. sodium bicarbonate until no more CO2 formation, then dried w/ anhydrous sodium sulfate for 5 hours. Simple distillation removed the diethyl ether first, then tert-amyl acetate distilled over at 125 °C.



Smells like grape candy.
Send me a U2U if you would like to request a small sample in the mail to smell it for yourself

Michael Bijan Afghani

[Edited on 24-11-2021 by MichaelBijanAfghani]

Fery - 23-11-2021 at 22:44

Hi Michael, well done!!! Very interesting reaction and ester !!! Especially the difficulty with a reactant alcohol prone to elimination thus hard to esterify.
Databases lack info about its scent, only few parameters reported (gravity, boiling point...)
http://www.thegoodscentscompany.com/data/rw1459651.html

MichaelBijanAfghani - 23-11-2021 at 22:48

Quote: Originally posted by Fery  
Hi Michael, well done!!! Very interesting reaction and ester !!! Especially the difficulty with a reactant alcohol prone to elimination thus hard to esterify.
Databases lack info about its scent, only few parameters reported (gravity, boiling point...)
http://www.thegoodscentscompany.com/data/rw1459651.html

I just noticed that Pubchem said it smells like bananas, and I can see (or smell) why it would say that, now that it mentioned it. I'd say it smells halfway between banana and grape.

The boiling point on good scents is completely wrong. 256 to 256 ­°C? Scifinder literature says 125 °C and I confirmed that.

Michael Bijan Afghani

[Edited on 24-11-2021 by MichaelBijanAfghani]

Fery - 24-11-2021 at 05:35

Hi Michael, yes b.p. of acetates does not differ from b.p. of corresponding alcohols too much.
b.p. of tert-butyl acetate is 82 C so I believe your boiling point, not the b.p. in the link.
So in you reaction the tertiary amine is used to capture HCl and ether for keeping reaction mixture at 40 C.
I tried to scent some esters which scents I was unable to identify by myself, only after reading information I realized yes that's true what is written. Sometimes I found that the written information was not correct, but that was maybe only my genetical variability?

Dr.Bob - 24-11-2021 at 17:30

Great job. I know that isoamyl acetate smells like bananas for sure, made that years ago, but have never smelled tert-amyl acetate, so that is neat. You could make a great smelling lab\, much better than alkyl isonitriles...

Bedlasky - 25-11-2021 at 05:27

Hi. I read about mangese(III) acetate catalysed synthesis of alkyl acetates with 99% efficiency (even in the case of reaction with tertiary alcohol).

https://sci-hub.st/https://www.sciencedirect.com/science/art...

DraconicAcid - 25-11-2021 at 08:12

That is an amazing paper, if it works. Does someone have a copy of the reference for the preparation of manganese(III) acetate?

E.I. Heiba, R.M. Dessau, W.J. Kolhl Jr., J. Am. Chem. Soc. 91
(1969) 138–145.

Bedlasky - 25-11-2021 at 08:25

Look at this:

https://www.designer-drug.com/pte/12.162.180.114/dcd/chemist...

I also saw video from Chem Player on this synthesis.