production of esters anyone?? (1 Viewer)

[magic_ethereal]

hey does anyone have any info on the production of esters

 

[rama_v]

What exactly do you need to know? Also, try http://community.boredofstudies.org/17/chemistry/25844/chemistry-summaries-resources.html and http://community.boredofstudies.org...-questions-answered-assistance-resources.html

 

[pLuvia]

http://en.wikipedia.org/wiki/Ester

 

[anarchron]

I believe it's called a Carboxylic Acid not an Alkanoic Acid.

Furthermore, I don't think the reaction is an acid/base reaction as there are no receiving and donating of protons and H2SO4 is only there acting as a catalyst and hence is neither consumed nor altered from the reaction.

 

[Riviet]

Carboxylic acids are organic acids characterized by the presence of a carboxyl group, which has the formula -C(=O)-OH, usually written as -COOH. The simplest series of carboxylic acids are the alkanoic acids, R-COOH, where R is a hydrogen or an alkyl group.

So basically a carboxylic acid can contain pretty much any other functional group so long as it contains the COOH group somewhere in the molecule. But an alkanoic acid is a specific type of carboxylic acid which only contains hydrogen, carbon and the COOH group. I hope that helps.

 

[passion89]

Remember that a little amount of acid is used as the catalyst - usually H₂SO₄

 

[Riviet]

A few drops of concentrated H₂SO₄ catalyst. It's important to be precise.

edit: thanks for clarifying that I-U.

 

[insert-username]

"dilute" H₂SO₄ catalyst. It's important to be precise.

Ummm... that should be a few drops of concentrated sulfuric acid, I think. That's definitely what we used. Dilute sulfuric acid is used when hydrating ethylene to make ethanol.


I_F

 

[miss india]

I believe it's called a Carboxylic Acid not an Alkanoic Acid.

Furthermore, I don't think the reaction is an acid/base reaction as there are no receiving and donating of protons and H2SO4 is only there acting as a catalyst and hence is neither consumed nor altered from the reaction.

alkanoic acids = carboxylic acids.
if u remember... ethanoic acid is named frm the alkane ethane...
and ethanoic acid has the functional grp COOH... which is the carboxylic acid grp....so basically, i think, vaishali is right.... coz alkanoic acid = carboxylic grp compounds.
on the other hand, u might like using different terminologies

 

[passion89]

"dilute" H₂SO₄ catalyst. It's important to be precise.

I think it's concentrated...though I'm not 100% sure
In class, while attempting this experiment, I remember none of the students were allowed to touch the container that the acid was in as it was soo concentrated.

 

[miss india]

Ummm... that should be a few drops of concentrated sulfuric acid, I think. That's definitely what we used. Dilute sulfuric acid is used when hydrating ethylene to make ethanol.


I_F

yes, even we used conc sulfuric acid...
coz it absorbs (or maybe adsorbs, i m not sure) the water molecule thats produced.... which increases the yield of the reaction and thus catalyses.

 

[insert-username]

alkanoic acids = carboxylic acids.
if u remember... ethanoic acid is named frm the alkane ethane...
and ethanoic acid has the functional grp COOH... which is the carboxylic acid grp....so basically, i think, vaishali is right.... coz alkanoic acid = carboxylic grp compounds.
on the other hand, u might like using different terminologies

It's a fine distinction. All alkanoic acids are carboxylic acids (contain COOH), but not all carboxylic acids are alkanoic acids. Alkanoic acids must be derived from alkane molecules, i.e. have a straight chain hydrocarbon with single bonds only (apart from the COOH group). Carboxylic acids on the other hand include things like citric acid (2-hydroxypropane-1,2,3-tricarboxylic acid), which is definitely not an alkanoic acid.


I_F

 

[pLuvia]

Carboxylic acids contain the -COOH group but can contain any other molecule, while alkanoic acids contain the -COOH group but only has carbons, hydrogens and oxygens attached to it.

And esterification is a reaction between alkanoic acids and alkanols

 

[miss india]

It's a fine distinction. All alkanoic acids are carboxylic acids (contain COOH), but not all carboxylic acids are alkanoic acids. Alkanoic acids must be derived from alkane molecules, i.e. have a straight chain hydrocarbon with single bonds only (apart from the COOH group). Carboxylic acids on the other hand include things like citric acid (2-hydroxypropane-1,2,3-tricarboxylic acid), which is definitely not an alkanoic acid.


I_F

sorry but i dont get why citric acid is not an alkanoic acid.....
coz its like made from basic alkanes after all......
yet again... i think the terminologies u might want to use may differ... causin differences in opinion!
dont kno

 

[Riviet]

Structural diagram of citric acid:

As you can see, citric acid does not consist of basic alkane molecules, therefore it can't be a an alkanoic acid.

 

[miss india]

uhhh ok
thanx

 

[niknik610]

can someone please tell me how the accuracy and reliability could be improved in esterification ?? like controlling the temperature...etc.?

 

[rama_v]

can someone please tell me how the accuracy and reliability could be improved in esterification ?? like controlling the temperature...etc.?

Filter the ester more times, Cary out reflux procedure for a longer period of time.

 

[[Damo]]

Don't forget, must have EXCESS of alkanol in reagents, say 10ml of Alkanoic acid and 12-15ml of Alkanol.

 

[tristambrown]

note catalyst is not needed, though speeds reaction up considerably. (eg if you have 6 hours to wait you can make Ethyl Ethanoate at home without having to find conc sulfuric acid)


most important thing here as far as increasing reliability points goes is REFLUX ... without reflux your reactants will boil away along with any of your product and make the whole thing a waste of time