Microwave-irradiated synthesis of nitrophen using PEG 400 as phase transfer catalyst and solvent

Abstract

Nitrophen is a widely used herbicide which is commonly produced by an energy intensive process using high temperature and pressure. In the current work, nitrophen is synthesized by using PEG-400 as a phase transfer catalyst in a solid−liquid (S-L) system from potassium 2,4-nitrophenolate and p-nitrochlorobenzene using xylene as a solvent under microwave irradiation. It gives 100% selectivity to nitrophen. The use of PEG-400 as a solvent was also examined both under microwaves and conventional heating at 120 °C. The synergism of microwave activation and S-L PTC using PEG 400 as a catalyst and solvent results in enhancements in the rate of reaction and selectivity of nitrophen. The proposed method for the synthesis of nitrofen reduces the total reaction time and also allows easy separation of the product. The kinetics and mechanism of S-L PTC and the homogeneous reaction were also established with PEG 400.