Test For Esters

the easiest technique would be to simply smell it. if it has a fruity/sweet smell, it's an ester.

chemically, you could either test for the alcohol (as you said), or test the carboxylic acid which is also produced, with sodium hydrogen carbonate, which results in co2 gas being released and the mixture turning cloudy:

NaHCO3 + CH3COOH → CH3CO2Na + H2O + CO2 (gas)

hope this helps!

Da Hool

Reply 2

thelostchild

one thing with your method is that if the ester was made with a tertiary alcohol then the Potassium Dichromate wouldnt react with it, so its not foolproof :smile:

Reply 3

burningnun

Could you measure the pH before/after hydrolysis? Surely it would be more acidic afterwards, if only slightly.

Reply 4

thelostchild

burningnun

Could you measure the pH before/after hydrolysis? Surely it would be more acidic afterwards, if only slightly.

the only problem with that is that to hydrolise it you either use an acid (HCl or H2SO4) or use NaOH both would effect the pH of the mixture anyway :smile:

Reply 5

DiscoPirate

Thanks for your replies!

Reply 6

charco

Study Forum Helper

You could hydrolyse the ester with a known amount of dilute acid and then titrate. An ester would show an increase in the amount of H+ ions (but so would an amide, an acid chloride and an acid anhydride)

There is no definitive test for an ester.

Reply 7

Miss_Scarlett

Would this work?

You could hydrolyse the ester with water and concentrated sulphuric acid catalyst. To give you your carboxyllic acid and alcohol. Then react the carb acid with a carbonate. As a carboxyllic acid is the only carbonyl compound to give off CO2 when this is done?

Alternatively you could smell it :biggrin: