Nitrosation and Nitration of Phenol

NITROSATION: phenol reacts readily with nitrous acid (HNO2) at low temperature (278 K) to give p-nitrosophenol as the major product. NITRATION: with 20% nitric acid even at room temperature (298 K), phenol gives a mixture of ortho- (30-40% yield) and para- (15% yield) nitrophenol; the two isomers are separated by steam distillation, since o-nitrophenol -- with intramolecular hydrogen bonding between its -OH and adjacent -NO2 -- is more volatile and less water-soluble, while p-nitrophenol, hydrogen-bonded intermolecularly, is less volatile and more water-soluble. With the stronger nitrating mixture …