[NusifGomes]

Hey guys, I've just carried out an esterification of 6-hydroxyhexanoic acid to 6-acetylhexanoic acid using acetic anhydride.

I then washed with ether and water, expecting the anhydride to hydrolyse in the water and be removed. This however hasn't happened and upon RoVapping off the ether, there's clearly plenty of anhydride left.
Would it be wise to work up with, say, HCl and then remove the acetic acid and chloride with a washing step? I've heard this reaction is very exothermic and not sure how very very is here.

Any other ideas would be great!

[clarkstill]

Presumably you mean the product is 6-acetoxyhexanoic acid?

I would just use a high-vac to remove the residual anhydride, but this might not be an option depending on your pump. According to this paper (https://pubs.acs.org/doi/pdf/10.1021/je60012a004) there is an 80 °C azeotrope between acetic anhydride and cyclohexane, so you should add cyclohexane to your residue a few times and vac it off to remove the residual anhydride.