Carboxylate Esters

[Swany]

I will assume you all know what esters are, go look it up at wikipedia if you don't. This thread is about carboxylate esters, not nitric acid esters. These esters make the smells responsible for the smells of fruit, and most other good smells in biochem.

 

To prepare an ester, you react an alcohol with a carboxylic acid. I used a few drops of conc. H2SO4 as a catalyst, refluxed for 30 mins, then distilled. I used azeotropic ethanol with benzoic acid to produce ethyl benzoate. Some diethyl ether may have also been produced.

 

Ethyl benzoate smells like... well, lots of things. Heavy fruity smell would be my description, however here is some good info: http://www.thegoodscentscompany.com/data/rw1004771.html

 

The wiki article has a list of esters and their smells. Have fun.

[TheSidewinder]

Wow, that's a blast from the past.

 

Way back in High School (1972) we made several extracts like that in Chem Lab, and ended up with strawberry, banana, and umm... one other one I can't remember now. Lemon?

 

And MAN did that stuff continue to stink long after we cleaned up everything!

 

One guy spilled some on his pants and had to go home to change. He showered, came back an hour later, and STILL smelled like a banana for the rest of the day. He claims he had to throw away his jeans because the smell would NOT wash out, and he tried several times.

 

For the life of me I can't remember the exact steps we took, but your decription of the process and chemicals used sounds VERY familiar. Neat.

 

M

[Mumbles]

I was helping a friend do a project in chem, and we made methyl salicyliate. I recomend not using ASA as the saliciliate source. For those unsure what I am talking about, asprin(ASA) is an acetylated form for salicylic acid. You can hydrolyse the acetyl group off, leaving pure salicylic acid. The smell of acetic acid overpowers the wintergreen smell of the methyl salicyliate.

 

We also made Banana (Propyl Acetate), Octyl Acetate(orange), Methyl Salicyliate(wintergreen), and something else in general chem. We had to do a bunch of crap, and the write up was basically what they smelled like. I already knew them all, and finished the writeup without taking out a beaker. The TA didn't believe that all the ester smells were common knowledge, even though I was right on every one, go figure.

 

Besides the good smelling esters, I also made a few other esters. I made some poly esters specifically. Resorcinol and Phthalic acid were combined, and refluxed in a solvent. Acetone I want to say with sulfuric acid present. I could smell some mesitylene being formed from the polymersation of the acetone from the acid. Water was added to crash out the polymer. Personally, I had better things in mind for the resourcinol and the phthalic acid.

[Swany]

Yes.... the lab smells of old ladies fruit perfume and success.

[FrKoNaLeaSh1010]

I remember doing the orange smelling ester in AP chem last year. Still smelt heavily of the acetic IIRc but deffinitely had a hint of oranges.

[asilentbob]

My lab group synthesized ASA and methyl salicylate last thursday, i keep thinking about making some more, perhaps ethyl salicylate (+ a bit of methyl salicylate, from denatured alcohol)... I would need to prepare some salicylic acid though... or go from aspirin? I don't even think that i have ASA around my house in any decent quantity...

[DDoS]

Today I made a ester from CH3COOH and azeotropic ethanole. (Don't know all organic names in english so I will write formulas). It didn't smell very pleasant at all ._. There was a bit pear smell. My teacher told that CH3CH3*CH3OH would give better product. Has anyone tryed it?

 

(Sorry if you have already discussed that. I really have no idea about C3H9OH name)

[Mumbles]

You probably had a lot left over Acetic Acid. I think Ethyl Acetate smells pretty good myself.