clear colorless to light yellow liquid
(R)-(-)-α-Methoxy-α-(trifluoromethyl)phenylacetyl chloride is used as a chiral acylating reagent, which is used in the resolution of amino acid enantiomers like 2,5-dimethoxy-4-methylamphetamine. It is also suitable for the determination of the optical composition of compounds extracted from biological fluids.
The most likely impurity is the free acid due to hydrolysis and should be checked by IR. If free from acid, then distil, taking care to keep moisture out of the apparatus. Otherwise add SOCl2 and reflux for 5hours and distil it. Note that shorter reflux times result in a higher boiling fraction (b 130-155o/1mm) which has been identified as the anhydride. [Dale et al. J Org Chem 34 2543 1969, for enantiomeric purity see Dale & Mosher J Am Chem Soc 97 512 1973.]
