Dissolve it in CH2Cl2 or CCl4 (1g in 30mL), wash it with H2O (30mL), brine (30mL), H2O (30 mL) again, dry (MgSO4 or Na2SO4), and evaporate. The residue in CH2Cl2 is chromatographed through Al2O3 (eluting with 10% EtOAc in hexane); evaporate, collect the correct fractions and distil (Kügelrohr) them. Log KNa in dry MeOH at 25o for Na+ complex is 2.08. [White et al. Tetrahedron Lett 26 151 1985, Arnold et al. J Org Chem 53 5652 1988.]