To remove the excess of unreacted benzyl alcohol and oleic acid, you can use a solvent such as an ethyl acetate or hexane. After the reaction is complete, you can use vacuum filtration to separate the crude product from the reaction mixture.

I removed many starting material from my product by adding some solvent in which either starting material is soluble or product is soluble. In your case i think you have to add diethyl ether and slightly heat it in water bath and filter it to remove benzyl alcohol and then wash with acetone to remove oleic acid.

To remove the acid, use a weak base as NaHCO3-Solution. But be carefull with shaking, the sodiumoleate will work as an emulsifier.

How great is th difference in boilinpoint of the ester and the alcohole? is maybe a rectification possible?

Best regards

Andreas