2,4-дихлорбензойной кислоты

Химические свойства

white powder

Использование

2,4-Dichlorobenzoic Acid is a di-halogenated benzoic acid derivative and an intermediate in the synthesis of spirodiclofen (S682990), a tetronic acid acaricide fungicide used in controlling red mites.

Определение

ChEBI: A chlorobenzoic acid that is benzoic acid in which the ring hydrogens at positions 2 and 4 are substituted by chloro groups.

Общее описание

White to slightly yellowish powder.

Реакции воздуха и воды

Insoluble in water.

Пожароопасность

Flash point data for 2,4-Dichlorobenzoic acid are not available; however, 2,4-Dichlorobenzoic acid is probably combustible.

Методы очистки

Crystallise the acid from aqueous EtOH (charcoal), then *benzene (charcoal). It can also be recrystallised from water. [Beilstein 9 IV 998.] It can be freed from isomeric acids (to <0.05%) via the (±)--methylbenzylamine salt as follows: dissolve the dichloro-acid (10g, 50.2mmol) in isopropanol (200mL), heat to 60o and add the (±)-benzylamine (5.49g, 45.3mmol), then stir it at 60o for 1hour. Cool the mixture to room temperature, filter the slurry, wash it with isopropanol (25mL) and dry it in vacuo at 40o overnight to give 79% of the salt with m 185.2o. Dissolve the salt (5g) in H2O (50mL) and MeOH (20mL), then heat to 60o and add concentrated HCl to pH <2.0. Cool the solution to room temperature add H2O (12mL), filter it, wash it with H2O (30mL) and dry it in vacuo at 40o overnight to give 94% of the acid with m 162.0o. [Ley & Yates Organic Process Research & Development 12 120 2008.]