Abstract : The process of nitration is the replacement of a hydrogen atom with a nitro group (NO2). The nitration, sulphonation, and halogenation reactions are extraordinarily facile due to the phenol's activated nucleus. Nitration occurs at room temperature with diluted HNO3. When phenols are treated with concentrated HNO3 in the presence of concentrated H¬2SO4, nitration occurs at both the ortho and para positions, producing picric acid. When — NO2 (nitro) groups are to be substituted for — SO3H (sulphonic acid) groups, it is preferable to convert phenol to phenol sulphonic acid with H¬2SO4 and then nitrate the compound with concentrated HNO3.
