Reflux the butanol with CaO, distil, reflux with magnesium and again fractionally distil it. A small sample of highly purified material is obtained by fractional crystallisation after conversion into a suitable ester such as the trinitrophthalate or the 3-nitrophthalate. The latter is converted to the cinchonine salt in acetone and recrystallised from CHCl3 by adding pentane. The salt is saponified, extracted with ether, and fractionally distilled. [Terry et al. J Chem Eng Data 5 403 1960, Beilstein 1 IV 1666.]
