6192-52-5

White crystals

Derivitizing agent.

Store at -20°C

Purify the acid by precipitation from a saturated solution at 0o by introducing HCl gas. It can also be crystallised from conc HCl, then crystallised from dilute HCl (charcoal) to remove benzenesulfonic acid. It has been crystallised from EtOH/water. Dry it in a vacuum desiccator over solid KOH and CaCl2. p-Toluenesulfonic acid can be dehydrated by azeotropic distillation with *benzene or by heating at 100o for 4hours under water-pump vacuum. The anhydrous acid can be crystallised from *benzene, CHCl3, ethyl acetate, anhydrous MeOH, or from acetone by adding a large excess of *benzene. It can also be dried under vacuum at 50o. The S-benzylisothiuronium salt has m 182o (from aqueous EtOH). [Beilstein 11 IV 241.]