For the purification of small quantities recrystallise it from pet ether (b 40-60o), but use MeOH or EtOH for larger quantities. For the latter solvent, dissolve 12.5g of chloride in 45mL of boiling EtOH (95%), filter and the filtrate yields colourless crystals (7.5g) on cooling. A further crop (0.9g) can be obtained by cooling in an ice-salt bath. It turns brown on exposure to sunlight but it is stable in sealed dark containers. The R(+)-enantiomer has m 75-76o (from pet ether) and []546.1 +168.4o (c 0.6, Me2CO) [Roger & Wood J Chem Soc 811 1954]. [Henley & Turner J Chem Soc 1182 1931, Ward Org Synth Coll Vol II 159 1943, Beilstein 7 H 436, 7 I 234, 7 II 369, 7 III 2106, 7 IV 1396.]
