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Purification Methods

Purify it by dissolving in H2O and passing through a strong cation exchange resin (H+ form). Evaporate the effluent under reduced pressure and dry the residue in a high vacuum to give colourless hygroscopic crystals [Dostal et al. Z Chem 6 153 1966 and IR: Dostál et al. Chem Ber 104 2044 1971]. [Beilstein 11 H 422, 11 I 111.]

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