Green Sonochemical Synthesis of Technical Fenitrothion Using Protic Ionic Liquid

In this study, a new environmentally friendly method for the synthesis of technical Fenitrothion is offered. Apart from using ionic liquid as the innocuous and recoverable solvent, this methodology offers sonochemical-assisted synthesis. Technical Fenitrothion has been obtained from the reaction of 3-methyl-4-nitrophenol as a critical intermediate in this green method. According to this methodology, m-cresol is nitrated by ferric nitrate as the nitrating agent in the presence of triethyl ammonium nitrate ionic liquid as a recoverable protic solvent under ultrasonic irradiation, in short reaction time and high yield. Ionic liquid caused more para selectivity of nitration by steric hindrance through hydrogen bond formation with phenolic oxygen, which inhibited ortho substitution of the aromatic ring, and 4-isomer obtained as the major product. The developed process provided task-specific ionic liquid preparation from by-products and the possibility of recycling the ionic liquid for five consecutive runs, which has the benefit of eliminating waste products generated out of this procedure following green chemistry principles.