EFFECT OF ULTRASOUND TREATMENT ON MAGNETIC AND CATALYTIC PROPERTIES OF IRON-CONTAINING MORDENITE IN THE REACTION OF BENZENE TO PHENOL OXIDATION BY HYDROGEN PEROXIDE IN LIQUID PHASE

Effect of ultrasonic treatment on magnetic and catalytic properties of iron-containing mordenite in reaction of liquid-phase hydroxylation of benzene to phenol with hydrogen peroxide was studied. Positive effect of ultrasonic treatment was established due to the increase in catalytic activity of iron-containing mordenite samples in hydroxylation of benzene into phenol. This result is achieved using ultrasonic treatment at a frequency of 26 kHz and with an exposure time of 5-60 min. at the stage of preparation of catalyst and in liquid-phase hydroxylation process. EMR spectroscopy data show that ultrasonic treatment of catalyst leads to dispersion and "homogenization" of FeOx magnetic phases. It was shown that the treatment of initial modenite samples with an aqueous-ammonium solution of iron(III) chloride with further calcination in air mainly leads to an increase in the concentration of magnetic phases FeOx. Data from DLS studies show that under influence of ultrasonic treatment cavitation particle size distribution curve in the liquid phase narrows significantly and the system becomes almost monodisperse. It was shown that it is possible to maintain activity of catalytic system which lost 80% of its activity after 4-6 h of reaction cycle by ultrasonic treatment treatment for 10 min. It was found that preliminary ultrasonic treatment of catalytic system along with maintaining it in a dispersed state cleans the surface of catalyst particles from oxidation products and leads to an increase in catalytic activity. The dependence of average particle diameter in catalytic system and magnetic properties of catalyst on time of ultrasonic treatment is determined