AAMC 4, #111, esters and solubility rules

[riseNshine]

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Hi guys,

For this problem, they say that there's a certain compound that's insoluble in water, but soluble in HCl and this compound yields an alcohol and carb acid. I know it must be an ester if it yields ethanol and carb acid but I thought esters were soluble in water due to the carbonyl so I ended up choosing another answer. Do we have to assume the ester had a large R group so it wouldn't be soluble?

 

[gtbROX]

Generally something is only soluble in water if it has a proportional amount of alcohol/amine functional groups to its total size or if it is charged. Esters don't have hydrogens to donate hydrogen bonds, they can only accept so they're not very water soluble, even the ones with small R groups.

 

[dontbeanegaton]

Even carboxylic acids are mostly insoluble in water if they are protonated. In any extraction problem you have to use a base to get the acid to dissolve in the aqueous phase.