Regioselective Nitration of Phenols by NaNO₃ in Microemulsion

Abstract

Highly regiospecific mononitration of phenols and substituted phenols was carried out in TX100-based microemulsion. The use of inexpensive and relatively nontoxic acidic reagent is an advantage of this method. The effect of various parameters such as concentration of NaNO₃, temperature, and agitation speed on reaction system have been investigated. Exclusive ortho-selectivity was observed for all the phenols subjected to this protocol.

Keywords:

• Hydrochloric acid
• microemulsion
• mononitration
• phenols

Acknowledgments

Financial support from the Fundamental Research Funds for the Central Universities (No. JUSRP20905) and Natural Science Foundation of Jiangnan University (No. 20071789 and No. 2008LYY005) is acknowledged.

Notes

^a Reaction condition: 0.8 mmol phenol, 1.6 mmol NaNO₃, and 0.8 mL dilute hydrochloric acid (10 mol/L) at 40°C. The conversions and selectivities were calculated from GC of the mixture by incorporating an internal standard.

^a Reaction condition: 0.8 mmol phenol, 0.8 mL dilute hydrochloric acid (10 mol/L), 8 mL TX100 microemulsion. The conversions and selectivities were calculated from GC of the mixture by incorporating an internal standard.

^a Reaction condition: 0.8 mmol phenol, 1.6 mmol NaNO₃, 0.8 mL dilute hydrochloric acid (10 mol/L), 8 mL TX100 microemulsion at 40°C. The yields were calculated from GC of the mixture by incorporating an internal standard.