Its suspension in water is stirred with enough 1M NaOH to dissolve most of it: a small amount of insoluble matter is removed by centrifugation. The chloromercuribenzoic acid is then precipitated by adding 1M HCl and centrifuged off. The precipitation is repeated twice. Finally, the precipitate is washed three times with distilled water (by centrifugation), then dried in a thin layer under vacuum over P2O5 [Boyer J Am Chem Soc 76 4331 1954]. Chloromethylphosphonic acid dichloride [1983 -26 -2] M 167.4, b 50o/0.5mm, 52 -53(59)o/2mm, 63-65o/3mm, 78 -79o/10mm, 87 -88o/15mm, 102-103o/30mm, d 4 1.638, n D 1.4971. It is fractionally distilled using a short Claisen column and redistilled. The aniline salt has m 199-201o. The 3 1P NMR has a single peak at -38±2 ppm from 85% H3PO4. [Kinnear & Perren J Chem Soc 3437 1952, NMR: van Wazer et al. J Am Chem Soc 78 5715 1956, McConnell et al. J Org Chem 22 462 1957, Beilstein 1 III 2593, 1 IV 3068.]
