pNitrobenzoic

p-Nitrobenzoic acid, often abbreviated as pNBA, is an organic compound with the molecular formula C7H5NO4. It is a derivative of benzoic acid, with a nitro group (-NO2) attached to the para position (position 4) of the benzene ring. This positioning distinguishes it from other nitrobenzoic acid isomers, such as o-nitrobenzoic acid and m-nitrobenzoic acid, where the nitro group is attached to the ortho (position 2) and meta (position 3) positions, respectively.

p-Nitrobenzoic acid is a yellow crystalline solid that is slightly soluble in water but more soluble in organic solvents like ethanol and ether. It is commonly used in various chemical reactions and syntheses due to its reactive nitro group. The compound can undergo reduction to form p-aminobenzoic acid, a precursor to various dyes and pharmaceuticals. It can also participate in electrophilic aromatic substitution reactions due to the activating effect of the nitro group.

In addition to its use in organic synthesis, p-nitrobenzoic acid is employed as an analytical reagent and in the preparation of certain pesticides and herbicides. It is also used in the study of enzyme kinetics, particularly in the assay of enzymes like horseradish peroxidase, where it serves as a substrate.

The compound should be handled with care, as it is a potential irritant and may cause skin and eye irritation. Appropriate safety measures, including the use of gloves and safety goggles, should be taken when handling p-nitrobenzoic acid. Proper disposal methods should also be followed to minimize environmental impact.