Hydrochloric Acid → 2,5-Dichlorophenylhydrazine oxalic acid

Participants

Reaction Conditions

Reaction Steps

To a 500 ml flask under a nitrogen atmosphere, concentrated HCl (180 ml, 32%, 10.17 M, 1.83 moles) was charged and cooled down to −2 to 0° C. 2,5-Dichloroaniline (30 g, 185 mmoles) was added in one portion as a solid. The acidic suspension was re-cooled to −2 to 0° C. and sodium nitrite (15.3 g, 222 mmoles) dissolved in water (30 ml) was added dropwise to the acidic mixture through an addition funnel over a period of 1 hour at −2 to 0° C. The resulting mixture was kept with stirring for 1 hour at −2 to 0° C. Next, L-ascorbic acid (34.2 g, 194 mmoles) was added portionwise as a solid at −2 to 0° C. The reaction mixture was allowed to come to room temperature (18-20° C.). A thick orange suspension was formed. The reaction mixture was diluted with concentrated HCl (50 ml, 32%, 0.51 moles, 2.7 eq) and water (150 ml) and then filtered. The wet solid was triturated in water (650 ml) at 20-25° C. for 16 hours, filtered, washed with water and dried to constant weight to afford 34 g of crude oxalic acid derivative as a red crystalline solid.

Provenance & Evidence