[elsa0902]

Hello all,

I am fairly new to organic chemistry, and have a quick question on a liquid-liquid extraction. If you were to trying to separate a thiol from a carboxylic acid using aqueous NaOH and an organic solvent, would both end up going into the water layer? They are both fairly acidic, and more so acidic than the water formed from each reacting so I am assuming separation of the two into the organic layer and water layer would not be this simple. Any input?

Thank you all in advance

[phth]

What is the pKa of both, and what does that tell you?

[elsa0902]

The pKa's tell me that the carboxylic acid is much more acidic and would react more readily with the sodium hydroxide, making it more likely to become ionized and go into the water layer. The thiol is still fairly acidic, however, so wouldn't it also be reacting with the sodium hydroxide?

[clarkstill]

They would probably (assuming neither is very large/lipophilic) both go into the aqueous, as you say both are easily acidic enough to be deprotonated by aqueous base. It might be possible using a buffer solution at a pH that lies between the pKa values of the acid (5) and thiol (10) but it could be a fairly thin line to tread.