Esters formulas (2 Viewers)

[kloudsurfer]

Hey,
I was away when we did this at school, and im struggling on how to write/draw the formulas and structural formulas of esters. I know how to write the formulas for alkanols and alkanoic acids etc but im just not sure how to write the formulas for the esters formed when they combine.

At the moment im trying to draw the strutural formula for the formation of methyl pentanoate. Could someone please explain how to draw it (or just a semi-structural formula if its too hard to do on the computer)?

Thanks in advance.

 

[xiao1985]

first part (ethyl) correspond to the alchonol you used, 2nd part (pentanoate) correspond to the alchonoic acid...

if you are given a structure and need to derive the name, you look at which carbon chain has 2 O's , and that chain would be the -oate part...

 

[Alfred_rulz]

Methyl Pentanoate

Esters from alkanols and alkanoic acid are named as alkyl alkanoates: the alkyl part of the name comes from the alcohol from which the ester was formed, and the alkanoate from the alkanoic acid.

In your case: Methyl Pentanoate -> Methanol + Pentanoic Acid

Hope you know the general formula for esterification process and your substances:

If not: Methanol: CH3 - OH
Pentanoic Acid: CH3 - CH2 - CH2 - CH2 - COOH
i.e. You must consider that the formula for pentanoic acid can change depending on where the carboxylic acid group is located. So in you case, let's take the general pentanoic acid: 1 - Pentanoic Acid.

Combining 1 - pentanoic acid and methanol gives us:

(CH3 - CH2 - CH2 - CH2 - C=O) - (O - CH3) + H2O

The products of the reaction are methyl pentanoate and water (brackets are only there for you to see better!).