Acquires a deep reddish-violet color if Schiff' s reagent is added. In contrast to the poorly soluble barium salt, the sodium salt is freely soluble in water; it is also freely soluble in hot, but not in cold, ethyl alcohol.
2-Sulfobenzaldehyde, is used for the synthesis of a series of novel 3-[N, N-bis(2-hydroxyethyl)-amino]-chalcone derivatives, having antimicrobial activity.
2-Formylbenzenesulfonic acid（sodium benzaldehyde-o-sulfonate) is an intermediate in the manufacture of optical brighteners, trade names including Uvitex NFW (for textiles) and Tinopal CBS (for detergents). Triphenylmethane dyes are produced by condensation of the acid with various N,N-dialkylani- lines, N,N-dialkyl-m-aminophenols, and their sulfonic acids.
The starting material is o-chlorobenzaldehyde, which is heated with sodium hydrogensulfite solution in an autoclave to 190 – 200 ℃,with the result that its chloro substituent is replaced by the sulfonic acid group. The batch is allowed to cool, sulfuric acid is added, and excess sulfur dioxide and unconverted chlorobenzaldehyde are driven off by boiling. The resulting solution is used directly in the manufacture of dyes. Sodium benzaldehyde-o-sulfonate can also be produced by oxidation of o-toluenesulfonic acid with oxygen in the presence of bromine and cobalt as catalysts.
