3-Nitrophthalic acid

Chemical properties

Pale yellow crystals. soluble in hot water, methanol, ethanol, slightly soluble in ether, insoluble in chloroform, carbon tetrachloride, carbon disulfide, benzene.

The Uses of 3-Nitrophthalic acid

3-Nitrophthalic Acid is a useful chemical in organic synthesis. It is also an impurity of Apremilast.

The Uses of 3-Nitrophthalic acid

3-Nitrophthalic acid may be used as starting reagent in the synthesis of modified 2-iodoxybenzoic acid derivatives. It may be used in the synthesis of brucinium 2-carboxy-6-nitrophthalate dihydrate (systematic name: 2,3-dimethoxy-10-oxostrychnidinium 2-carboxy-6-nitrophthalate dihydrate), via heating with brucine.

What are the applications of Application

3-Nitrophthalic acid can be used for:
(1) Hydrogenation. It has been shown that 3-nitrophthalic acid is reduced to 3-aminophthalic acid in the presence of 5% palladium charcoal in glacial acetic acid at room temperature and atmospheric pressure. Further reaction gives 3-acetamido phthalic acid.
(2) Anti-corrosion effect. It can be used as a new type of corrosion inhibitor, in order to improve the corrosion resistance life of steel structures in acidic media.The anti-corrosion behaviour of 3-nitrophthalic acid is achieved by the surface smoothness and the hydrophobic film generated by the adsorption of the inhibitor on the surface of mild steel.
(3) Other effects. Acts as a ligand and forms rare earth complexes and spectral analysis studies.

Preparation

Phthalic anhydride was added to concentrated sulfuric acid, stirring under the passage of water vapor heating to 80 °C, fuming nitric acid was added dropwise, the reaction temperature to maintain 100-110°C, add the end of the heat above 110°C for 2h, placed in the overnight pour into the water, and filtered. The filter cake was recrystallized with water to obtain 3-Nitrophthalic acid. Yield of about 30%.

Synthesis

The synthesis of 3-nitrophthalic acid has been achieved by catalytic oxidation of 1-nitronaphthalene using γ-alumina supported ceria(IV) as a catalyst at 363 K in 80 mol% yield with 98% selectivity.

Synthesis Reference(s)

The Journal of Organic Chemistry, 39, p. 2468, 1974 DOI: 10.1021/jo00930a051

General Description

3-Nitrophthalic acid is a degradation product of isoxaben herbicide. It acts as ligand and forms rare-earth complexes.

Safety Profile

A preparative hazard. When heated to decomposition it emits toxic fumes of NOx.

Purification Methods

Crystallise 3-nitrophthalic acid from hot water (1.5mL/g). Dry it in air. The amide has m 201o (from EtOH). [Beilstein 9 H 823, 9 IV 3275.]