3,5-Dichlorobenzoic acid

Chemical properties

White to beige powder

The Uses of 3,5-Dichlorobenzoic acid

3,5-Dichlorobenzoic acid is used in organic synthesis and pesticide and pharmaceutical intermediates. It can be used to synthesize 3,5-Dichloro-N-(4-hydroxyphenethyl)benzamide and (3,5-Dichlorophenyl)-(4-fluorophenyl)methanone.

Definition

ChEBI: 3,5-dichlorobenzoic acid is a chlorobenzoic acid that is benzoic acid in which the ring hydrogens at positions 3 and 5 are substituted by chloro groups. It has a role as a herbicide and a metabolite. It is a chlorobenzoic acid and a dichlorobenzene. It derives from a benzoic acid. It is a conjugate acid of a 3,5-dichlorobenzoate.

Preparation

Synthesis of 3,5-dichlorobenzoic acid: 200 parts of ethanol is slowly added to a solution, heated to 70°C, of the diazonium salt prepared as described in Example 1 from 412 parts of 3,5-dichloroanthranilic acid; elimination of nitrogen immediately takes place with evolution of heat. The mixture is stirred for another 15 minutes and 350 parts (92% of theory) of 3,5-dichlorobenzoic acid having a melting point of 176° to 178°C is isolated as described in Example 1.

Synthesis Reference(s)

Journal of the American Chemical Society, 73, p. 455, 1951 DOI: 10.1021/ja01145a145

Purification Methods

Crystallise the acid from EtOH and sublime it in a vacuum. [Beilstein 9 IV 1008.] Aromatic acid impurities (to <0.05%) can be removed via the (±)--methylbenzylamine salt as described for 2,4-dichlorobenzoic acid [Ley & Yates Organic Process Research & Development 12 120 2008.]